openapi: 3.0.2
servers:
  - url: http://optimade.local
info:
  description: |-
    The [Open Databases Integration for Materials Design (OPTIMADE) consortium](https://www.optimade.org/) aims to make materials databases interoperational by developing a common REST API.

    This specification is generated using [`optimade-python-tools`](https://github.com/Materials-Consortia/optimade-python-tools/tree/v0.16.0) v0.16.0.
  title: OPTIMADE API
  version: 1.1.0~develop
  x-apisguru-categories:
    - open_data
  x-origin:
    - format: openapi
      url: https://raw.githubusercontent.com/Materials-Consortia/OPTIMADE/master/schemas/openapi_schema.json
      version: "3.0"
  x-providerName: optimade.local
  x-logo:
    url: https://api.apis.guru/v2/cache/logo/https_apis.guru_assets_images_no-logo.svg
paths:
  /info:
    get:
      operationId: get_info_info_get
      responses:
        "200":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/InfoResponse"
          description: Successful Response
        "400":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Bad Request
        "403":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Forbidden
        "404":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Not Found
        "422":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Unprocessable Entity
        "500":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Internal Server Error
        "501":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Not Implemented
        "553":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Version Not Supported
      summary: Get Info
      tags:
        - Info
  "/info/{entry}":
    get:
      operationId: get_entry_info_info__entry__get
      parameters:
        - in: path
          name: entry
          required: true
          schema:
            title: Entry
            type: string
      responses:
        "200":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/EntryInfoResponse"
          description: Successful Response
        "400":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Bad Request
        "403":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Forbidden
        "404":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Not Found
        "422":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Unprocessable Entity
        "500":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Internal Server Error
        "501":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Not Implemented
        "553":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Version Not Supported
      summary: Get Entry Info
      tags:
        - Info
  /links:
    get:
      operationId: get_links_links_get
      parameters:
        - description: A filter string, in the format described in section API Filtering Format Specification of the specification.
          in: query
          name: filter
          required: false
          schema:
            default: ""
            description: A filter string, in the format described in section API Filtering Format Specification of the specification.
            title: Filter
            type: string
        - description: |-
            The output format requested (see section Response Format).
            Defaults to the format string 'json', which specifies the standard output format described in this specification.
            Example: `http://example.com/v1/structures?response_format=xml`
          in: query
          name: response_format
          required: false
          schema:
            default: json
            description: |-
              The output format requested (see section Response Format).
              Defaults to the format string 'json', which specifies the standard output format described in this specification.
              Example: `http://example.com/v1/structures?response_format=xml`
            title: Response Format
            type: string
        - description: |-
            An email address of the user making the request.
            The email SHOULD be that of a person and not an automatic system.
            Example: `http://example.com/v1/structures?email_address=user@example.com`
          in: query
          name: email_address
          required: false
          schema:
            default: ""
            description: |-
              An email address of the user making the request.
              The email SHOULD be that of a person and not an automatic system.
              Example: `http://example.com/v1/structures?email_address=user@example.com`
            format: email
            title: Email Address
            type: string
        - description: |-
            A comma-delimited set of fields to be provided in the output.
            If provided, these fields MUST be returned along with the REQUIRED fields.
            Other OPTIONAL fields MUST NOT be returned when this parameter is present.
            Example: `http://example.com/v1/structures?response_fields=last_modified,nsites`
          in: query
          name: response_fields
          required: false
          schema:
            default: ""
            description: |-
              A comma-delimited set of fields to be provided in the output.
              If provided, these fields MUST be returned along with the REQUIRED fields.
              Other OPTIONAL fields MUST NOT be returned when this parameter is present.
              Example: `http://example.com/v1/structures?response_fields=last_modified,nsites`
            pattern: ([a-z_][a-z_0-9]*(,[a-z_][a-z_0-9]*)*)?
            title: Response Fields
            type: string
        - description: |-
            If supporting sortable queries, an implementation MUST use the `sort` query parameter with format as specified by [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-sorting).

            An implementation MAY support multiple sort fields for a single query.
            If it does, it again MUST conform to the JSON API 1.0 specification.

            If an implementation supports sorting for an entry listing endpoint, then the `/info/<entries>` endpoint MUST include, for each field name `<fieldname>` in its `data.properties.<fieldname>` response value that can be used for sorting, the key `sortable` with value `true`.
            If a field name under an entry listing endpoint supporting sorting cannot be used for sorting, the server MUST either leave out the `sortable` key or set it equal to `false` for the specific field name.
            The set of field names, with `sortable` equal to `true` are allowed to be used in the "sort fields" list according to its definition in the JSON API 1.0 specification.
            The field `sortable` is in addition to each property description and other OPTIONAL fields.
            An example is shown in the section Entry Listing Info Endpoints.
          in: query
          name: sort
          required: false
          schema:
            default: ""
            description: |-
              If supporting sortable queries, an implementation MUST use the `sort` query parameter with format as specified by [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-sorting).

              An implementation MAY support multiple sort fields for a single query.
              If it does, it again MUST conform to the JSON API 1.0 specification.

              If an implementation supports sorting for an entry listing endpoint, then the `/info/<entries>` endpoint MUST include, for each field name `<fieldname>` in its `data.properties.<fieldname>` response value that can be used for sorting, the key `sortable` with value `true`.
              If a field name under an entry listing endpoint supporting sorting cannot be used for sorting, the server MUST either leave out the `sortable` key or set it equal to `false` for the specific field name.
              The set of field names, with `sortable` equal to `true` are allowed to be used in the "sort fields" list according to its definition in the JSON API 1.0 specification.
              The field `sortable` is in addition to each property description and other OPTIONAL fields.
              An example is shown in the section Entry Listing Info Endpoints.
            pattern: ([a-z_][a-z_0-9]*(,[a-z_][a-z_0-9]*)*)?
            title: Sort
            type: string
        - description: |-
            Sets a numerical limit on the number of entries returned.
            See [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-pagination).
            The API implementation MUST return no more than the number specified.
            It MAY return fewer.
            The database MAY have a maximum limit and not accept larger numbers (in which case an error code -- 403 Forbidden -- MUST be returned).
            The default limit value is up to the API implementation to decide.
            Example: `http://example.com/optimade/v1/structures?page_limit=100`
          in: query
          name: page_limit
          required: false
          schema:
            default: 20
            description: |-
              Sets a numerical limit on the number of entries returned.
              See [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-pagination).
              The API implementation MUST return no more than the number specified.
              It MAY return fewer.
              The database MAY have a maximum limit and not accept larger numbers (in which case an error code -- 403 Forbidden -- MUST be returned).
              The default limit value is up to the API implementation to decide.
              Example: `http://example.com/optimade/v1/structures?page_limit=100`
            minimum: 0
            title: Page Limit
            type: integer
        - description: |-
            RECOMMENDED for use with _offset-based_ pagination: using `page_offset` and `page_limit` is RECOMMENDED.
            Example: Skip 50 structures and fetch up to 100: `/structures?page_offset=50&page_limit=100`.
          in: query
          name: page_offset
          required: false
          schema:
            default: 0
            description: |-
              RECOMMENDED for use with _offset-based_ pagination: using `page_offset` and `page_limit` is RECOMMENDED.
              Example: Skip 50 structures and fetch up to 100: `/structures?page_offset=50&page_limit=100`.
            minimum: 0
            title: Page Offset
            type: integer
        - description: |-
            RECOMMENDED for use with _page-based_ pagination: using `page_number` and `page_limit` is RECOMMENDED.
            It is RECOMMENDED that the first page has number 1, i.e., that `page_number` is 1-based.
            Example: Fetch page 2 of up to 50 structures per page: `/structures?page_number=2&page_limit=50`.
          in: query
          name: page_number
          required: false
          schema:
            default: 0
            description: |-
              RECOMMENDED for use with _page-based_ pagination: using `page_number` and `page_limit` is RECOMMENDED.
              It is RECOMMENDED that the first page has number 1, i.e., that `page_number` is 1-based.
              Example: Fetch page 2 of up to 50 structures per page: `/structures?page_number=2&page_limit=50`.
            minimum: 0
            title: Page Number
            type: integer
        - description: "RECOMMENDED for use with _cursor-based_ pagination: using `page_cursor` and `page_limit` is RECOMMENDED."
          in: query
          name: page_cursor
          required: false
          schema:
            default: 0
            description: "RECOMMENDED for use with _cursor-based_ pagination: using `page_cursor` and `page_limit` is RECOMMENDED."
            minimum: 0
            title: Page Cursor
            type: integer
        - description: |-
            RECOMMENDED for use with _value-based_ pagination: using `page_above`/`page_below` and `page_limit` is RECOMMENDED.
            Example: Fetch up to 100 structures above sort-field value 4000 (in this example, server chooses to fetch results sorted by increasing `id`, so `page_above` value refers to an `id` value): `/structures?page_above=4000&page_limit=100`.
          in: query
          name: page_above
          required: false
          schema:
            default: 0
            description: |-
              RECOMMENDED for use with _value-based_ pagination: using `page_above`/`page_below` and `page_limit` is RECOMMENDED.
              Example: Fetch up to 100 structures above sort-field value 4000 (in this example, server chooses to fetch results sorted by increasing `id`, so `page_above` value refers to an `id` value): `/structures?page_above=4000&page_limit=100`.
            minimum: 0
            title: Page Above
            type: integer
        - description: "RECOMMENDED for use with _value-based_ pagination: using `page_above`/`page_below` and `page_limit` is RECOMMENDED."
          in: query
          name: page_below
          required: false
          schema:
            default: 0
            description: "RECOMMENDED for use with _value-based_ pagination: using `page_above`/`page_below` and `page_limit` is RECOMMENDED."
            minimum: 0
            title: Page Below
            type: integer
        - description: |-
            A server MAY implement the JSON API concept of returning [compound documents](https://jsonapi.org/format/1.0/#document-compound-documents) by utilizing the `include` query parameter as specified by [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-includes).

            All related resource objects MUST be returned as part of an array value for the top-level `included` field, see the section JSON Response Schema: Common Fields.

            The value of `include` MUST be a comma-separated list of "relationship paths", as defined in the [JSON API](https://jsonapi.org/format/1.0/#fetching-includes).
            If relationship paths are not supported, or a server is unable to identify a relationship path a `400 Bad Request` response MUST be made.

            The **default value** for `include` is `references`.
            This means `references` entries MUST always be included under the top-level field `included` as default, since a server assumes if `include` is not specified by a client in the request, it is still specified as `include=references`.
            Note, if a client explicitly specifies `include` and leaves out `references`, `references` resource objects MUST NOT be included under the top-level field `included`, as per the definition of `included`, see section JSON Response Schema: Common Fields.

            > **Note**: A query with the parameter `include` set to the empty string means no related resource objects are to be returned under the top-level field `included`.
          in: query
          name: include
          required: false
          schema:
            default: references
            description: |-
              A server MAY implement the JSON API concept of returning [compound documents](https://jsonapi.org/format/1.0/#document-compound-documents) by utilizing the `include` query parameter as specified by [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-includes).

              All related resource objects MUST be returned as part of an array value for the top-level `included` field, see the section JSON Response Schema: Common Fields.

              The value of `include` MUST be a comma-separated list of "relationship paths", as defined in the [JSON API](https://jsonapi.org/format/1.0/#fetching-includes).
              If relationship paths are not supported, or a server is unable to identify a relationship path a `400 Bad Request` response MUST be made.

              The **default value** for `include` is `references`.
              This means `references` entries MUST always be included under the top-level field `included` as default, since a server assumes if `include` is not specified by a client in the request, it is still specified as `include=references`.
              Note, if a client explicitly specifies `include` and leaves out `references`, `references` resource objects MUST NOT be included under the top-level field `included`, as per the definition of `included`, see section JSON Response Schema: Common Fields.

              > **Note**: A query with the parameter `include` set to the empty string means no related resource objects are to be returned under the top-level field `included`.
            title: Include
            type: string
        - description: If the client provides the parameter, the value SHOULD have the format `vMAJOR` or `vMAJOR.MINOR`, where MAJOR is a major version and MINOR is a minor version of the API. For example, if a client appends `api_hint=v1.0` to the query string, the hint provided is for major version 1 and minor version 0.
          in: query
          name: api_hint
          required: false
          schema:
            default: ""
            description: If the client provides the parameter, the value SHOULD have the format `vMAJOR` or `vMAJOR.MINOR`, where MAJOR is a major version and MINOR is a minor version of the API. For example, if a client appends `api_hint=v1.0` to the query string, the hint provided is for major version 1 and minor version 0.
            pattern: (v[0-9]+(\.[0-9]+)?)?
            title: Api Hint
            type: string
      responses:
        "200":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/LinksResponse"
          description: Successful Response
        "400":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Bad Request
        "403":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Forbidden
        "404":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Not Found
        "422":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Unprocessable Entity
        "500":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Internal Server Error
        "501":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Not Implemented
        "553":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Version Not Supported
      summary: Get Links
      tags:
        - Links
  /references:
    get:
      operationId: get_references_references_get
      parameters:
        - description: A filter string, in the format described in section API Filtering Format Specification of the specification.
          in: query
          name: filter
          required: false
          schema:
            default: ""
            description: A filter string, in the format described in section API Filtering Format Specification of the specification.
            title: Filter
            type: string
        - description: |-
            The output format requested (see section Response Format).
            Defaults to the format string 'json', which specifies the standard output format described in this specification.
            Example: `http://example.com/v1/structures?response_format=xml`
          in: query
          name: response_format
          required: false
          schema:
            default: json
            description: |-
              The output format requested (see section Response Format).
              Defaults to the format string 'json', which specifies the standard output format described in this specification.
              Example: `http://example.com/v1/structures?response_format=xml`
            title: Response Format
            type: string
        - description: |-
            An email address of the user making the request.
            The email SHOULD be that of a person and not an automatic system.
            Example: `http://example.com/v1/structures?email_address=user@example.com`
          in: query
          name: email_address
          required: false
          schema:
            default: ""
            description: |-
              An email address of the user making the request.
              The email SHOULD be that of a person and not an automatic system.
              Example: `http://example.com/v1/structures?email_address=user@example.com`
            format: email
            title: Email Address
            type: string
        - description: |-
            A comma-delimited set of fields to be provided in the output.
            If provided, these fields MUST be returned along with the REQUIRED fields.
            Other OPTIONAL fields MUST NOT be returned when this parameter is present.
            Example: `http://example.com/v1/structures?response_fields=last_modified,nsites`
          in: query
          name: response_fields
          required: false
          schema:
            default: ""
            description: |-
              A comma-delimited set of fields to be provided in the output.
              If provided, these fields MUST be returned along with the REQUIRED fields.
              Other OPTIONAL fields MUST NOT be returned when this parameter is present.
              Example: `http://example.com/v1/structures?response_fields=last_modified,nsites`
            pattern: ([a-z_][a-z_0-9]*(,[a-z_][a-z_0-9]*)*)?
            title: Response Fields
            type: string
        - description: |-
            If supporting sortable queries, an implementation MUST use the `sort` query parameter with format as specified by [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-sorting).

            An implementation MAY support multiple sort fields for a single query.
            If it does, it again MUST conform to the JSON API 1.0 specification.

            If an implementation supports sorting for an entry listing endpoint, then the `/info/<entries>` endpoint MUST include, for each field name `<fieldname>` in its `data.properties.<fieldname>` response value that can be used for sorting, the key `sortable` with value `true`.
            If a field name under an entry listing endpoint supporting sorting cannot be used for sorting, the server MUST either leave out the `sortable` key or set it equal to `false` for the specific field name.
            The set of field names, with `sortable` equal to `true` are allowed to be used in the "sort fields" list according to its definition in the JSON API 1.0 specification.
            The field `sortable` is in addition to each property description and other OPTIONAL fields.
            An example is shown in the section Entry Listing Info Endpoints.
          in: query
          name: sort
          required: false
          schema:
            default: ""
            description: |-
              If supporting sortable queries, an implementation MUST use the `sort` query parameter with format as specified by [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-sorting).

              An implementation MAY support multiple sort fields for a single query.
              If it does, it again MUST conform to the JSON API 1.0 specification.

              If an implementation supports sorting for an entry listing endpoint, then the `/info/<entries>` endpoint MUST include, for each field name `<fieldname>` in its `data.properties.<fieldname>` response value that can be used for sorting, the key `sortable` with value `true`.
              If a field name under an entry listing endpoint supporting sorting cannot be used for sorting, the server MUST either leave out the `sortable` key or set it equal to `false` for the specific field name.
              The set of field names, with `sortable` equal to `true` are allowed to be used in the "sort fields" list according to its definition in the JSON API 1.0 specification.
              The field `sortable` is in addition to each property description and other OPTIONAL fields.
              An example is shown in the section Entry Listing Info Endpoints.
            pattern: ([a-z_][a-z_0-9]*(,[a-z_][a-z_0-9]*)*)?
            title: Sort
            type: string
        - description: |-
            Sets a numerical limit on the number of entries returned.
            See [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-pagination).
            The API implementation MUST return no more than the number specified.
            It MAY return fewer.
            The database MAY have a maximum limit and not accept larger numbers (in which case an error code -- 403 Forbidden -- MUST be returned).
            The default limit value is up to the API implementation to decide.
            Example: `http://example.com/optimade/v1/structures?page_limit=100`
          in: query
          name: page_limit
          required: false
          schema:
            default: 20
            description: |-
              Sets a numerical limit on the number of entries returned.
              See [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-pagination).
              The API implementation MUST return no more than the number specified.
              It MAY return fewer.
              The database MAY have a maximum limit and not accept larger numbers (in which case an error code -- 403 Forbidden -- MUST be returned).
              The default limit value is up to the API implementation to decide.
              Example: `http://example.com/optimade/v1/structures?page_limit=100`
            minimum: 0
            title: Page Limit
            type: integer
        - description: |-
            RECOMMENDED for use with _offset-based_ pagination: using `page_offset` and `page_limit` is RECOMMENDED.
            Example: Skip 50 structures and fetch up to 100: `/structures?page_offset=50&page_limit=100`.
          in: query
          name: page_offset
          required: false
          schema:
            default: 0
            description: |-
              RECOMMENDED for use with _offset-based_ pagination: using `page_offset` and `page_limit` is RECOMMENDED.
              Example: Skip 50 structures and fetch up to 100: `/structures?page_offset=50&page_limit=100`.
            minimum: 0
            title: Page Offset
            type: integer
        - description: |-
            RECOMMENDED for use with _page-based_ pagination: using `page_number` and `page_limit` is RECOMMENDED.
            It is RECOMMENDED that the first page has number 1, i.e., that `page_number` is 1-based.
            Example: Fetch page 2 of up to 50 structures per page: `/structures?page_number=2&page_limit=50`.
          in: query
          name: page_number
          required: false
          schema:
            default: 0
            description: |-
              RECOMMENDED for use with _page-based_ pagination: using `page_number` and `page_limit` is RECOMMENDED.
              It is RECOMMENDED that the first page has number 1, i.e., that `page_number` is 1-based.
              Example: Fetch page 2 of up to 50 structures per page: `/structures?page_number=2&page_limit=50`.
            minimum: 0
            title: Page Number
            type: integer
        - description: "RECOMMENDED for use with _cursor-based_ pagination: using `page_cursor` and `page_limit` is RECOMMENDED."
          in: query
          name: page_cursor
          required: false
          schema:
            default: 0
            description: "RECOMMENDED for use with _cursor-based_ pagination: using `page_cursor` and `page_limit` is RECOMMENDED."
            minimum: 0
            title: Page Cursor
            type: integer
        - description: |-
            RECOMMENDED for use with _value-based_ pagination: using `page_above`/`page_below` and `page_limit` is RECOMMENDED.
            Example: Fetch up to 100 structures above sort-field value 4000 (in this example, server chooses to fetch results sorted by increasing `id`, so `page_above` value refers to an `id` value): `/structures?page_above=4000&page_limit=100`.
          in: query
          name: page_above
          required: false
          schema:
            default: 0
            description: |-
              RECOMMENDED for use with _value-based_ pagination: using `page_above`/`page_below` and `page_limit` is RECOMMENDED.
              Example: Fetch up to 100 structures above sort-field value 4000 (in this example, server chooses to fetch results sorted by increasing `id`, so `page_above` value refers to an `id` value): `/structures?page_above=4000&page_limit=100`.
            minimum: 0
            title: Page Above
            type: integer
        - description: "RECOMMENDED for use with _value-based_ pagination: using `page_above`/`page_below` and `page_limit` is RECOMMENDED."
          in: query
          name: page_below
          required: false
          schema:
            default: 0
            description: "RECOMMENDED for use with _value-based_ pagination: using `page_above`/`page_below` and `page_limit` is RECOMMENDED."
            minimum: 0
            title: Page Below
            type: integer
        - description: |-
            A server MAY implement the JSON API concept of returning [compound documents](https://jsonapi.org/format/1.0/#document-compound-documents) by utilizing the `include` query parameter as specified by [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-includes).

            All related resource objects MUST be returned as part of an array value for the top-level `included` field, see the section JSON Response Schema: Common Fields.

            The value of `include` MUST be a comma-separated list of "relationship paths", as defined in the [JSON API](https://jsonapi.org/format/1.0/#fetching-includes).
            If relationship paths are not supported, or a server is unable to identify a relationship path a `400 Bad Request` response MUST be made.

            The **default value** for `include` is `references`.
            This means `references` entries MUST always be included under the top-level field `included` as default, since a server assumes if `include` is not specified by a client in the request, it is still specified as `include=references`.
            Note, if a client explicitly specifies `include` and leaves out `references`, `references` resource objects MUST NOT be included under the top-level field `included`, as per the definition of `included`, see section JSON Response Schema: Common Fields.

            > **Note**: A query with the parameter `include` set to the empty string means no related resource objects are to be returned under the top-level field `included`.
          in: query
          name: include
          required: false
          schema:
            default: references
            description: |-
              A server MAY implement the JSON API concept of returning [compound documents](https://jsonapi.org/format/1.0/#document-compound-documents) by utilizing the `include` query parameter as specified by [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-includes).

              All related resource objects MUST be returned as part of an array value for the top-level `included` field, see the section JSON Response Schema: Common Fields.

              The value of `include` MUST be a comma-separated list of "relationship paths", as defined in the [JSON API](https://jsonapi.org/format/1.0/#fetching-includes).
              If relationship paths are not supported, or a server is unable to identify a relationship path a `400 Bad Request` response MUST be made.

              The **default value** for `include` is `references`.
              This means `references` entries MUST always be included under the top-level field `included` as default, since a server assumes if `include` is not specified by a client in the request, it is still specified as `include=references`.
              Note, if a client explicitly specifies `include` and leaves out `references`, `references` resource objects MUST NOT be included under the top-level field `included`, as per the definition of `included`, see section JSON Response Schema: Common Fields.

              > **Note**: A query with the parameter `include` set to the empty string means no related resource objects are to be returned under the top-level field `included`.
            title: Include
            type: string
        - description: If the client provides the parameter, the value SHOULD have the format `vMAJOR` or `vMAJOR.MINOR`, where MAJOR is a major version and MINOR is a minor version of the API. For example, if a client appends `api_hint=v1.0` to the query string, the hint provided is for major version 1 and minor version 0.
          in: query
          name: api_hint
          required: false
          schema:
            default: ""
            description: If the client provides the parameter, the value SHOULD have the format `vMAJOR` or `vMAJOR.MINOR`, where MAJOR is a major version and MINOR is a minor version of the API. For example, if a client appends `api_hint=v1.0` to the query string, the hint provided is for major version 1 and minor version 0.
            pattern: (v[0-9]+(\.[0-9]+)?)?
            title: Api Hint
            type: string
      responses:
        "200":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ReferenceResponseMany"
          description: Successful Response
        "400":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Bad Request
        "403":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Forbidden
        "404":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Not Found
        "422":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Unprocessable Entity
        "500":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Internal Server Error
        "501":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Not Implemented
        "553":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Version Not Supported
      summary: Get References
      tags:
        - References
  "/references/{entry_id}":
    get:
      operationId: get_single_reference_references__entry_id__get
      parameters:
        - in: path
          name: entry_id
          required: true
          schema:
            title: Entry Id
            type: string
        - description: |-
            The output format requested (see section Response Format).
            Defaults to the format string 'json', which specifies the standard output format described in this specification.
            Example: `http://example.com/v1/structures?response_format=xml`
          in: query
          name: response_format
          required: false
          schema:
            default: json
            description: |-
              The output format requested (see section Response Format).
              Defaults to the format string 'json', which specifies the standard output format described in this specification.
              Example: `http://example.com/v1/structures?response_format=xml`
            title: Response Format
            type: string
        - description: |-
            An email address of the user making the request.
            The email SHOULD be that of a person and not an automatic system.
            Example: `http://example.com/v1/structures?email_address=user@example.com`
          in: query
          name: email_address
          required: false
          schema:
            default: ""
            description: |-
              An email address of the user making the request.
              The email SHOULD be that of a person and not an automatic system.
              Example: `http://example.com/v1/structures?email_address=user@example.com`
            format: email
            title: Email Address
            type: string
        - description: |-
            A comma-delimited set of fields to be provided in the output.
            If provided, these fields MUST be returned along with the REQUIRED fields.
            Other OPTIONAL fields MUST NOT be returned when this parameter is present.
            Example: `http://example.com/v1/structures?response_fields=last_modified,nsites`
          in: query
          name: response_fields
          required: false
          schema:
            default: ""
            description: |-
              A comma-delimited set of fields to be provided in the output.
              If provided, these fields MUST be returned along with the REQUIRED fields.
              Other OPTIONAL fields MUST NOT be returned when this parameter is present.
              Example: `http://example.com/v1/structures?response_fields=last_modified,nsites`
            pattern: ([a-z_][a-z_0-9]*(,[a-z_][a-z_0-9]*)*)?
            title: Response Fields
            type: string
        - description: |-
            A server MAY implement the JSON API concept of returning [compound documents](https://jsonapi.org/format/1.0/#document-compound-documents) by utilizing the `include` query parameter as specified by [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-includes).

            All related resource objects MUST be returned as part of an array value for the top-level `included` field, see the section JSON Response Schema: Common Fields.

            The value of `include` MUST be a comma-separated list of "relationship paths", as defined in the [JSON API](https://jsonapi.org/format/1.0/#fetching-includes).
            If relationship paths are not supported, or a server is unable to identify a relationship path a `400 Bad Request` response MUST be made.

            The **default value** for `include` is `references`.
            This means `references` entries MUST always be included under the top-level field `included` as default, since a server assumes if `include` is not specified by a client in the request, it is still specified as `include=references`.
            Note, if a client explicitly specifies `include` and leaves out `references`, `references` resource objects MUST NOT be included under the top-level field `included`, as per the definition of `included`, see section JSON Response Schema: Common Fields.

            > **Note**: A query with the parameter `include` set to the empty string means no related resource objects are to be returned under the top-level field `included`.
          in: query
          name: include
          required: false
          schema:
            default: references
            description: |-
              A server MAY implement the JSON API concept of returning [compound documents](https://jsonapi.org/format/1.0/#document-compound-documents) by utilizing the `include` query parameter as specified by [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-includes).

              All related resource objects MUST be returned as part of an array value for the top-level `included` field, see the section JSON Response Schema: Common Fields.

              The value of `include` MUST be a comma-separated list of "relationship paths", as defined in the [JSON API](https://jsonapi.org/format/1.0/#fetching-includes).
              If relationship paths are not supported, or a server is unable to identify a relationship path a `400 Bad Request` response MUST be made.

              The **default value** for `include` is `references`.
              This means `references` entries MUST always be included under the top-level field `included` as default, since a server assumes if `include` is not specified by a client in the request, it is still specified as `include=references`.
              Note, if a client explicitly specifies `include` and leaves out `references`, `references` resource objects MUST NOT be included under the top-level field `included`, as per the definition of `included`, see section JSON Response Schema: Common Fields.

              > **Note**: A query with the parameter `include` set to the empty string means no related resource objects are to be returned under the top-level field `included`.
            title: Include
            type: string
        - description: If the client provides the parameter, the value SHOULD have the format `vMAJOR` or `vMAJOR.MINOR`, where MAJOR is a major version and MINOR is a minor version of the API. For example, if a client appends `api_hint=v1.0` to the query string, the hint provided is for major version 1 and minor version 0.
          in: query
          name: api_hint
          required: false
          schema:
            default: ""
            description: If the client provides the parameter, the value SHOULD have the format `vMAJOR` or `vMAJOR.MINOR`, where MAJOR is a major version and MINOR is a minor version of the API. For example, if a client appends `api_hint=v1.0` to the query string, the hint provided is for major version 1 and minor version 0.
            pattern: (v[0-9]+(\.[0-9]+)?)?
            title: Api Hint
            type: string
      responses:
        "200":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ReferenceResponseOne"
          description: Successful Response
        "400":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Bad Request
        "403":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Forbidden
        "404":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Not Found
        "422":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Unprocessable Entity
        "500":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Internal Server Error
        "501":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Not Implemented
        "553":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Version Not Supported
      summary: Get Single Reference
      tags:
        - References
  /structures:
    get:
      operationId: get_structures_structures_get
      parameters:
        - description: A filter string, in the format described in section API Filtering Format Specification of the specification.
          in: query
          name: filter
          required: false
          schema:
            default: ""
            description: A filter string, in the format described in section API Filtering Format Specification of the specification.
            title: Filter
            type: string
        - description: |-
            The output format requested (see section Response Format).
            Defaults to the format string 'json', which specifies the standard output format described in this specification.
            Example: `http://example.com/v1/structures?response_format=xml`
          in: query
          name: response_format
          required: false
          schema:
            default: json
            description: |-
              The output format requested (see section Response Format).
              Defaults to the format string 'json', which specifies the standard output format described in this specification.
              Example: `http://example.com/v1/structures?response_format=xml`
            title: Response Format
            type: string
        - description: |-
            An email address of the user making the request.
            The email SHOULD be that of a person and not an automatic system.
            Example: `http://example.com/v1/structures?email_address=user@example.com`
          in: query
          name: email_address
          required: false
          schema:
            default: ""
            description: |-
              An email address of the user making the request.
              The email SHOULD be that of a person and not an automatic system.
              Example: `http://example.com/v1/structures?email_address=user@example.com`
            format: email
            title: Email Address
            type: string
        - description: |-
            A comma-delimited set of fields to be provided in the output.
            If provided, these fields MUST be returned along with the REQUIRED fields.
            Other OPTIONAL fields MUST NOT be returned when this parameter is present.
            Example: `http://example.com/v1/structures?response_fields=last_modified,nsites`
          in: query
          name: response_fields
          required: false
          schema:
            default: ""
            description: |-
              A comma-delimited set of fields to be provided in the output.
              If provided, these fields MUST be returned along with the REQUIRED fields.
              Other OPTIONAL fields MUST NOT be returned when this parameter is present.
              Example: `http://example.com/v1/structures?response_fields=last_modified,nsites`
            pattern: ([a-z_][a-z_0-9]*(,[a-z_][a-z_0-9]*)*)?
            title: Response Fields
            type: string
        - description: |-
            If supporting sortable queries, an implementation MUST use the `sort` query parameter with format as specified by [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-sorting).

            An implementation MAY support multiple sort fields for a single query.
            If it does, it again MUST conform to the JSON API 1.0 specification.

            If an implementation supports sorting for an entry listing endpoint, then the `/info/<entries>` endpoint MUST include, for each field name `<fieldname>` in its `data.properties.<fieldname>` response value that can be used for sorting, the key `sortable` with value `true`.
            If a field name under an entry listing endpoint supporting sorting cannot be used for sorting, the server MUST either leave out the `sortable` key or set it equal to `false` for the specific field name.
            The set of field names, with `sortable` equal to `true` are allowed to be used in the "sort fields" list according to its definition in the JSON API 1.0 specification.
            The field `sortable` is in addition to each property description and other OPTIONAL fields.
            An example is shown in the section Entry Listing Info Endpoints.
          in: query
          name: sort
          required: false
          schema:
            default: ""
            description: |-
              If supporting sortable queries, an implementation MUST use the `sort` query parameter with format as specified by [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-sorting).

              An implementation MAY support multiple sort fields for a single query.
              If it does, it again MUST conform to the JSON API 1.0 specification.

              If an implementation supports sorting for an entry listing endpoint, then the `/info/<entries>` endpoint MUST include, for each field name `<fieldname>` in its `data.properties.<fieldname>` response value that can be used for sorting, the key `sortable` with value `true`.
              If a field name under an entry listing endpoint supporting sorting cannot be used for sorting, the server MUST either leave out the `sortable` key or set it equal to `false` for the specific field name.
              The set of field names, with `sortable` equal to `true` are allowed to be used in the "sort fields" list according to its definition in the JSON API 1.0 specification.
              The field `sortable` is in addition to each property description and other OPTIONAL fields.
              An example is shown in the section Entry Listing Info Endpoints.
            pattern: ([a-z_][a-z_0-9]*(,[a-z_][a-z_0-9]*)*)?
            title: Sort
            type: string
        - description: |-
            Sets a numerical limit on the number of entries returned.
            See [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-pagination).
            The API implementation MUST return no more than the number specified.
            It MAY return fewer.
            The database MAY have a maximum limit and not accept larger numbers (in which case an error code -- 403 Forbidden -- MUST be returned).
            The default limit value is up to the API implementation to decide.
            Example: `http://example.com/optimade/v1/structures?page_limit=100`
          in: query
          name: page_limit
          required: false
          schema:
            default: 20
            description: |-
              Sets a numerical limit on the number of entries returned.
              See [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-pagination).
              The API implementation MUST return no more than the number specified.
              It MAY return fewer.
              The database MAY have a maximum limit and not accept larger numbers (in which case an error code -- 403 Forbidden -- MUST be returned).
              The default limit value is up to the API implementation to decide.
              Example: `http://example.com/optimade/v1/structures?page_limit=100`
            minimum: 0
            title: Page Limit
            type: integer
        - description: |-
            RECOMMENDED for use with _offset-based_ pagination: using `page_offset` and `page_limit` is RECOMMENDED.
            Example: Skip 50 structures and fetch up to 100: `/structures?page_offset=50&page_limit=100`.
          in: query
          name: page_offset
          required: false
          schema:
            default: 0
            description: |-
              RECOMMENDED for use with _offset-based_ pagination: using `page_offset` and `page_limit` is RECOMMENDED.
              Example: Skip 50 structures and fetch up to 100: `/structures?page_offset=50&page_limit=100`.
            minimum: 0
            title: Page Offset
            type: integer
        - description: |-
            RECOMMENDED for use with _page-based_ pagination: using `page_number` and `page_limit` is RECOMMENDED.
            It is RECOMMENDED that the first page has number 1, i.e., that `page_number` is 1-based.
            Example: Fetch page 2 of up to 50 structures per page: `/structures?page_number=2&page_limit=50`.
          in: query
          name: page_number
          required: false
          schema:
            default: 0
            description: |-
              RECOMMENDED for use with _page-based_ pagination: using `page_number` and `page_limit` is RECOMMENDED.
              It is RECOMMENDED that the first page has number 1, i.e., that `page_number` is 1-based.
              Example: Fetch page 2 of up to 50 structures per page: `/structures?page_number=2&page_limit=50`.
            minimum: 0
            title: Page Number
            type: integer
        - description: "RECOMMENDED for use with _cursor-based_ pagination: using `page_cursor` and `page_limit` is RECOMMENDED."
          in: query
          name: page_cursor
          required: false
          schema:
            default: 0
            description: "RECOMMENDED for use with _cursor-based_ pagination: using `page_cursor` and `page_limit` is RECOMMENDED."
            minimum: 0
            title: Page Cursor
            type: integer
        - description: |-
            RECOMMENDED for use with _value-based_ pagination: using `page_above`/`page_below` and `page_limit` is RECOMMENDED.
            Example: Fetch up to 100 structures above sort-field value 4000 (in this example, server chooses to fetch results sorted by increasing `id`, so `page_above` value refers to an `id` value): `/structures?page_above=4000&page_limit=100`.
          in: query
          name: page_above
          required: false
          schema:
            default: 0
            description: |-
              RECOMMENDED for use with _value-based_ pagination: using `page_above`/`page_below` and `page_limit` is RECOMMENDED.
              Example: Fetch up to 100 structures above sort-field value 4000 (in this example, server chooses to fetch results sorted by increasing `id`, so `page_above` value refers to an `id` value): `/structures?page_above=4000&page_limit=100`.
            minimum: 0
            title: Page Above
            type: integer
        - description: "RECOMMENDED for use with _value-based_ pagination: using `page_above`/`page_below` and `page_limit` is RECOMMENDED."
          in: query
          name: page_below
          required: false
          schema:
            default: 0
            description: "RECOMMENDED for use with _value-based_ pagination: using `page_above`/`page_below` and `page_limit` is RECOMMENDED."
            minimum: 0
            title: Page Below
            type: integer
        - description: |-
            A server MAY implement the JSON API concept of returning [compound documents](https://jsonapi.org/format/1.0/#document-compound-documents) by utilizing the `include` query parameter as specified by [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-includes).

            All related resource objects MUST be returned as part of an array value for the top-level `included` field, see the section JSON Response Schema: Common Fields.

            The value of `include` MUST be a comma-separated list of "relationship paths", as defined in the [JSON API](https://jsonapi.org/format/1.0/#fetching-includes).
            If relationship paths are not supported, or a server is unable to identify a relationship path a `400 Bad Request` response MUST be made.

            The **default value** for `include` is `references`.
            This means `references` entries MUST always be included under the top-level field `included` as default, since a server assumes if `include` is not specified by a client in the request, it is still specified as `include=references`.
            Note, if a client explicitly specifies `include` and leaves out `references`, `references` resource objects MUST NOT be included under the top-level field `included`, as per the definition of `included`, see section JSON Response Schema: Common Fields.

            > **Note**: A query with the parameter `include` set to the empty string means no related resource objects are to be returned under the top-level field `included`.
          in: query
          name: include
          required: false
          schema:
            default: references
            description: |-
              A server MAY implement the JSON API concept of returning [compound documents](https://jsonapi.org/format/1.0/#document-compound-documents) by utilizing the `include` query parameter as specified by [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-includes).

              All related resource objects MUST be returned as part of an array value for the top-level `included` field, see the section JSON Response Schema: Common Fields.

              The value of `include` MUST be a comma-separated list of "relationship paths", as defined in the [JSON API](https://jsonapi.org/format/1.0/#fetching-includes).
              If relationship paths are not supported, or a server is unable to identify a relationship path a `400 Bad Request` response MUST be made.

              The **default value** for `include` is `references`.
              This means `references` entries MUST always be included under the top-level field `included` as default, since a server assumes if `include` is not specified by a client in the request, it is still specified as `include=references`.
              Note, if a client explicitly specifies `include` and leaves out `references`, `references` resource objects MUST NOT be included under the top-level field `included`, as per the definition of `included`, see section JSON Response Schema: Common Fields.

              > **Note**: A query with the parameter `include` set to the empty string means no related resource objects are to be returned under the top-level field `included`.
            title: Include
            type: string
        - description: If the client provides the parameter, the value SHOULD have the format `vMAJOR` or `vMAJOR.MINOR`, where MAJOR is a major version and MINOR is a minor version of the API. For example, if a client appends `api_hint=v1.0` to the query string, the hint provided is for major version 1 and minor version 0.
          in: query
          name: api_hint
          required: false
          schema:
            default: ""
            description: If the client provides the parameter, the value SHOULD have the format `vMAJOR` or `vMAJOR.MINOR`, where MAJOR is a major version and MINOR is a minor version of the API. For example, if a client appends `api_hint=v1.0` to the query string, the hint provided is for major version 1 and minor version 0.
            pattern: (v[0-9]+(\.[0-9]+)?)?
            title: Api Hint
            type: string
      responses:
        "200":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/StructureResponseMany"
          description: Successful Response
        "400":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Bad Request
        "403":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Forbidden
        "404":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Not Found
        "422":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Unprocessable Entity
        "500":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Internal Server Error
        "501":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Not Implemented
        "553":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Version Not Supported
      summary: Get Structures
      tags:
        - Structures
  "/structures/{entry_id}":
    get:
      operationId: get_single_structure_structures__entry_id__get
      parameters:
        - in: path
          name: entry_id
          required: true
          schema:
            title: Entry Id
            type: string
        - description: |-
            The output format requested (see section Response Format).
            Defaults to the format string 'json', which specifies the standard output format described in this specification.
            Example: `http://example.com/v1/structures?response_format=xml`
          in: query
          name: response_format
          required: false
          schema:
            default: json
            description: |-
              The output format requested (see section Response Format).
              Defaults to the format string 'json', which specifies the standard output format described in this specification.
              Example: `http://example.com/v1/structures?response_format=xml`
            title: Response Format
            type: string
        - description: |-
            An email address of the user making the request.
            The email SHOULD be that of a person and not an automatic system.
            Example: `http://example.com/v1/structures?email_address=user@example.com`
          in: query
          name: email_address
          required: false
          schema:
            default: ""
            description: |-
              An email address of the user making the request.
              The email SHOULD be that of a person and not an automatic system.
              Example: `http://example.com/v1/structures?email_address=user@example.com`
            format: email
            title: Email Address
            type: string
        - description: |-
            A comma-delimited set of fields to be provided in the output.
            If provided, these fields MUST be returned along with the REQUIRED fields.
            Other OPTIONAL fields MUST NOT be returned when this parameter is present.
            Example: `http://example.com/v1/structures?response_fields=last_modified,nsites`
          in: query
          name: response_fields
          required: false
          schema:
            default: ""
            description: |-
              A comma-delimited set of fields to be provided in the output.
              If provided, these fields MUST be returned along with the REQUIRED fields.
              Other OPTIONAL fields MUST NOT be returned when this parameter is present.
              Example: `http://example.com/v1/structures?response_fields=last_modified,nsites`
            pattern: ([a-z_][a-z_0-9]*(,[a-z_][a-z_0-9]*)*)?
            title: Response Fields
            type: string
        - description: |-
            A server MAY implement the JSON API concept of returning [compound documents](https://jsonapi.org/format/1.0/#document-compound-documents) by utilizing the `include` query parameter as specified by [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-includes).

            All related resource objects MUST be returned as part of an array value for the top-level `included` field, see the section JSON Response Schema: Common Fields.

            The value of `include` MUST be a comma-separated list of "relationship paths", as defined in the [JSON API](https://jsonapi.org/format/1.0/#fetching-includes).
            If relationship paths are not supported, or a server is unable to identify a relationship path a `400 Bad Request` response MUST be made.

            The **default value** for `include` is `references`.
            This means `references` entries MUST always be included under the top-level field `included` as default, since a server assumes if `include` is not specified by a client in the request, it is still specified as `include=references`.
            Note, if a client explicitly specifies `include` and leaves out `references`, `references` resource objects MUST NOT be included under the top-level field `included`, as per the definition of `included`, see section JSON Response Schema: Common Fields.

            > **Note**: A query with the parameter `include` set to the empty string means no related resource objects are to be returned under the top-level field `included`.
          in: query
          name: include
          required: false
          schema:
            default: references
            description: |-
              A server MAY implement the JSON API concept of returning [compound documents](https://jsonapi.org/format/1.0/#document-compound-documents) by utilizing the `include` query parameter as specified by [JSON API 1.0](https://jsonapi.org/format/1.0/#fetching-includes).

              All related resource objects MUST be returned as part of an array value for the top-level `included` field, see the section JSON Response Schema: Common Fields.

              The value of `include` MUST be a comma-separated list of "relationship paths", as defined in the [JSON API](https://jsonapi.org/format/1.0/#fetching-includes).
              If relationship paths are not supported, or a server is unable to identify a relationship path a `400 Bad Request` response MUST be made.

              The **default value** for `include` is `references`.
              This means `references` entries MUST always be included under the top-level field `included` as default, since a server assumes if `include` is not specified by a client in the request, it is still specified as `include=references`.
              Note, if a client explicitly specifies `include` and leaves out `references`, `references` resource objects MUST NOT be included under the top-level field `included`, as per the definition of `included`, see section JSON Response Schema: Common Fields.

              > **Note**: A query with the parameter `include` set to the empty string means no related resource objects are to be returned under the top-level field `included`.
            title: Include
            type: string
        - description: If the client provides the parameter, the value SHOULD have the format `vMAJOR` or `vMAJOR.MINOR`, where MAJOR is a major version and MINOR is a minor version of the API. For example, if a client appends `api_hint=v1.0` to the query string, the hint provided is for major version 1 and minor version 0.
          in: query
          name: api_hint
          required: false
          schema:
            default: ""
            description: If the client provides the parameter, the value SHOULD have the format `vMAJOR` or `vMAJOR.MINOR`, where MAJOR is a major version and MINOR is a minor version of the API. For example, if a client appends `api_hint=v1.0` to the query string, the hint provided is for major version 1 and minor version 0.
            pattern: (v[0-9]+(\.[0-9]+)?)?
            title: Api Hint
            type: string
      responses:
        "200":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/StructureResponseOne"
          description: Successful Response
        "400":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Bad Request
        "403":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Forbidden
        "404":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Not Found
        "422":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Unprocessable Entity
        "500":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Internal Server Error
        "501":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Not Implemented
        "553":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
          description: Version Not Supported
      summary: Get Single Structure
      tags:
        - Structures
  /versions:
    get:
      description: Respond with the text/csv representation for the served versions.
      operationId: get_versions_versions_get
      responses:
        "200":
          content:
            text/csv; header=present:
              schema:
                type: string
          description: Successful Response
      summary: Get Versions
      tags:
        - Versions
components:
  schemas:
    Aggregate:
      description: Enumeration of aggregate values
      enum:
        - ok
        - test
        - staging
        - no
      title: Aggregate
    Assembly:
      description: |-
        A description of groups of sites that are statistically correlated.

        - **Examples** (for each entry of the assemblies list):
            - `{"sites_in_groups": [[0], [1]], "group_probabilities: [0.3, 0.7]}`: the first site and the second site never occur at the same time in the unit cell.
              Statistically, 30 % of the times the first site is present, while 70 % of the times the second site is present.
            - `{"sites_in_groups": [[1,2], [3]], "group_probabilities: [0.3, 0.7]}`: the second and third site are either present together or not present; they form the first group of atoms for this assembly.
              The second group is formed by the fourth site. Sites of the first group (the second and the third) are never present at the same time as the fourth site.
              30 % of times sites 1 and 2 are present (and site 3 is absent); 70 % of times site 3 is present (and sites 1 and 2 are absent).
      properties:
        group_probabilities:
          description: |-
            Statistical probability of each group. It MUST have the same length as `sites_in_groups`.
            It SHOULD sum to one.
            See below for examples of how to specify the probability of the occurrence of a vacancy.
            The possible reasons for the values not to sum to one are the same as already specified above for the `concentration` of each `species`.
          items:
            type: number
          title: Group Probabilities
          type: array
        sites_in_groups:
          description: |-
            Index of the sites (0-based) that belong to each group for each assembly.

            - **Examples**:
                - `[[1], [2]]`: two groups, one with the second site, one with the third.
                - `[[1,2], [3]]`: one group with the second and third site, one with the fourth.
          items:
            items:
              type: integer
            type: array
          title: Sites In Groups
          type: array
      required:
        - sites_in_groups
        - group_probabilities
      title: Assembly
      type: object
    Attributes:
      description: |-
        Members of the attributes object ("attributes") represent information about the resource object in which it's defined.
        The keys for Attributes MUST NOT be:
            relationships
            links
            id
            type
      properties: {}
      title: Attributes
      type: object
    AvailableApiVersion:
      description: A JSON object containing information about an available API version
      properties:
        url:
          description: A string specifying a versioned base URL that MUST adhere to the rules in section Base URL
          format: uri
          maxLength: 65536
          minLength: 1
          pattern: .+/v[0-1](\.[0-9]+)*/?$
          title: Url
          type: string
        version:
          description: |-
            A string containing the full version number of the API served at that versioned base URL.
            The version number string MUST NOT be prefixed by, e.g., 'v'.
            Examples: `1.0.0`, `1.0.0-rc.2`.
          pattern: ^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-((?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)(?:\.(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*))?(?:\+([0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?$
          title: Version
          type: string
      required:
        - url
        - version
      title: AvailableApiVersion
      type: object
    BaseInfoAttributes:
      description: Attributes for Base URL Info endpoint
      properties:
        api_version:
          description: |-
            Presently used full version of the OPTIMADE API.
            The version number string MUST NOT be prefixed by, e.g., "v".
            Examples: `1.0.0`, `1.0.0-rc.2`.
          pattern: ^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-((?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)(?:\.(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*))?(?:\+([0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?$
          title: Api Version
          type: string
        available_api_versions:
          description: A list of dictionaries of available API versions at other base URLs
          items:
            $ref: "#/components/schemas/AvailableApiVersion"
          title: Available Api Versions
          type: array
        available_endpoints:
          description: List of available endpoints (i.e., the string to be appended to the versioned base URL).
          items:
            type: string
          title: Available Endpoints
          type: array
        entry_types_by_format:
          additionalProperties:
            items:
              type: string
            type: array
          description: Available entry endpoints as a function of output formats.
          title: Entry Types By Format
          type: object
        formats:
          default:
            - json
          description: List of available output formats.
          items:
            type: string
          title: Formats
          type: array
        is_index:
          default: false
          description: If true, this is an index meta-database base URL (see section Index Meta-Database). If this member is not provided, the client MUST assume this is not an index meta-database base URL (i.e., the default is for `is_index` to be `false`).
          title: Is Index
          type: boolean
      required:
        - api_version
        - available_api_versions
        - available_endpoints
        - entry_types_by_format
      title: BaseInfoAttributes
      type: object
    BaseInfoResource:
      description: Resource objects appear in a JSON API document to represent resources.
      properties:
        attributes:
          $ref: "#/components/schemas/BaseInfoAttributes"
        id:
          pattern: ^/$
          title: Id
          type: string
        links:
          allOf:
            - $ref: "#/components/schemas/ResourceLinks"
          description: a links object containing links related to the resource.
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/Meta"
          description: a meta object containing non-standard meta-information about a resource that can not be represented as an attribute or relationship.
          title: Meta
        relationships:
          allOf:
            - $ref: "#/components/schemas/Relationships"
          description: |-
            [Relationships object](https://jsonapi.org/format/1.0/#document-resource-object-relationships)
            describing relationships between the resource and other JSON API resources.
          title: Relationships
        type:
          pattern: ^info$
          title: Type
          type: string
      required:
        - id
        - type
        - attributes
      title: BaseInfoResource
      type: object
    BaseRelationshipMeta:
      description: Specific meta field for base relationship resource
      properties:
        description:
          description: OPTIONAL human-readable description of the relationship
          title: Description
          type: string
      required:
        - description
      title: BaseRelationshipMeta
      type: object
    BaseRelationshipResource:
      description: Minimum requirements to represent a relationship resource
      properties:
        id:
          description: Resource ID
          title: Id
          type: string
        meta:
          allOf:
            - $ref: "#/components/schemas/BaseRelationshipMeta"
          description: Relationship meta field. MUST contain 'description' if supplied.
          title: Meta
        type:
          description: Resource type
          title: Type
          type: string
      required:
        - id
        - type
      title: BaseRelationshipResource
      type: object
    DataType:
      description: |-
        Optimade Data Types

        See the section "Data types" in the OPTIMADE API specification for more information.
      enum:
        - string
        - integer
        - float
        - boolean
        - timestamp
        - list
        - dictionary
        - unknown
      title: DataType
    EntryInfoProperty:
      properties:
        description:
          description: A human-readable description of the entry property
          title: Description
          type: string
        sortable:
          description: |-
            Defines whether the entry property can be used for sorting with the "sort" parameter.
            If the entry listing endpoint supports sorting, this key MUST be present for sortable properties with value `true`.
          title: Sortable
          type: boolean
        type:
          allOf:
            - $ref: "#/components/schemas/DataType"
          description: |-
            The type of the property's value.
            This MUST be any of the types defined in the Data types section.
            For the purpose of compatibility with future versions of this specification, a client MUST accept values that are not `string` values specifying any of the OPTIMADE Data types, but MUST then also disregard the `type` field.
            Note, if the value is a nested type, only the outermost type should be reported.
            E.g., for the entry resource `structures`, the `species` property is defined as a list of dictionaries, hence its `type` value would be `list`.
          title: Type
        unit:
          description: |-
            The physical unit of the entry property.
            This MUST be a valid representation of units according to version 2.1 of [The Unified Code for Units of Measure](https://unitsofmeasure.org/ucum.html).
            It is RECOMMENDED that non-standard (non-SI) units are described in the description for the property.
          title: Unit
          type: string
      required:
        - description
      title: EntryInfoProperty
      type: object
    EntryInfoResource:
      properties:
        description:
          description: Description of the entry.
          title: Description
          type: string
        formats:
          description: List of output formats available for this type of entry.
          items:
            type: string
          title: Formats
          type: array
        output_fields_by_format:
          additionalProperties:
            items:
              type: string
            type: array
          description: Dictionary of available output fields for this entry type, where the keys are the values of the `formats` list and the values are the keys of the `properties` dictionary.
          title: Output Fields By Format
          type: object
        properties:
          additionalProperties:
            $ref: "#/components/schemas/EntryInfoProperty"
          description: A dictionary describing queryable properties for this entry type, where each key is a property name.
          title: Properties
          type: object
      required:
        - formats
        - description
        - properties
        - output_fields_by_format
      title: EntryInfoResource
      type: object
    EntryInfoResponse:
      description: errors are not allowed
      properties:
        data:
          allOf:
            - $ref: "#/components/schemas/EntryInfoResource"
          description: OPTIMADE information for an entry endpoint
          title: Data
        errors:
          description: A list of unique errors
          items:
            $ref: "#/components/schemas/Error"
          title: Errors
          type: array
          uniqueItems: true
        included:
          description: A list of unique included resources
          items:
            $ref: "#/components/schemas/Resource"
          title: Included
          type: array
          uniqueItems: true
        jsonapi:
          allOf:
            - $ref: "#/components/schemas/JsonApi"
          description: Information about the JSON API used
          title: Jsonapi
        links:
          allOf:
            - $ref: "#/components/schemas/ToplevelLinks"
          description: Links associated with the primary data or errors
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/ResponseMeta"
          description: A meta object containing non-standard information
          title: Meta
      required:
        - data
        - meta
      title: EntryInfoResponse
      type: object
    EntryRelationships:
      description: This model wraps the JSON API Relationships to include type-specific top level keys.
      properties:
        references:
          allOf:
            - $ref: "#/components/schemas/ReferenceRelationship"
          description: Object containing links to relationships with entries of the `references` type.
          title: References
        structures:
          allOf:
            - $ref: "#/components/schemas/StructureRelationship"
          description: Object containing links to relationships with entries of the `structures` type.
          title: Structures
      title: EntryRelationships
      type: object
    EntryResource:
      description: The base model for an entry resource.
      properties:
        attributes:
          allOf:
            - $ref: "#/components/schemas/EntryResourceAttributes"
          description: |-
            A dictionary, containing key-value pairs representing the entry's properties, except for `type` and `id`.
            Database-provider-specific properties need to include the database-provider-specific prefix (see section on Database-Provider-Specific Namespace Prefixes).
          title: Attributes
        id:
          description: |-
            An entry's ID as defined in section Definition of Terms.

            - **Type**: string.

            - **Requirements/Conventions**:
                - **Support**: MUST be supported by all implementations, MUST NOT be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.
                - **Response**: REQUIRED in the response.

            - **Examples**:
                - `"db/1234567"`
                - `"cod/2000000"`
                - `"cod/2000000@1234567"`
                - `"nomad/L1234567890"`
                - `"42"`
          title: Id
          type: string
        links:
          allOf:
            - $ref: "#/components/schemas/ResourceLinks"
          description: a links object containing links related to the resource.
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/Meta"
          description: a meta object containing non-standard meta-information about a resource that can not be represented as an attribute or relationship.
          title: Meta
        relationships:
          allOf:
            - $ref: "#/components/schemas/EntryRelationships"
          description: |-
            A dictionary containing references to other entries according to the description in section Relationships encoded as [JSON API Relationships](https://jsonapi.org/format/1.0/#document-resource-object-relationships).
            The OPTIONAL human-readable description of the relationship MAY be provided in the `description` field inside the `meta` dictionary of the JSON API resource identifier object.
          title: Relationships
        type:
          description: |-
            The name of the type of an entry.

            - **Type**: string.

            - **Requirements/Conventions**:
                - **Support**: MUST be supported by all implementations, MUST NOT be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.
                - **Response**: REQUIRED in the response.
                - MUST be an existing entry type.
                - The entry of type `<type>` and ID `<id>` MUST be returned in response to a request for `/<type>/<id>` under the versioned base URL.

            - **Example**: `"structures"`
          title: Type
          type: string
      required:
        - id
        - type
        - attributes
      title: EntryResource
      type: object
    EntryResourceAttributes:
      description: Contains key-value pairs representing the entry's properties.
      properties:
        immutable_id:
          description: |-
            The entry's immutable ID (e.g., an UUID). This is important for databases having preferred IDs that point to "the latest version" of a record, but still offer access to older variants. This ID maps to the version-specific record, in case it changes in the future.

            - **Type**: string.

            - **Requirements/Conventions**:
                - **Support**: OPTIONAL support in implementations, i.e., MAY be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.

            - **Examples**:
                - `"8bd3e750-b477-41a0-9b11-3a799f21b44f"`
                - `"fjeiwoj,54;@=%<>#32"` (Strings that are not URL-safe are allowed.)
          title: Immutable Id
          type: string
        last_modified:
          description: |-
            Date and time representing when the entry was last modified.

            - **Type**: timestamp.

            - **Requirements/Conventions**:
                - **Support**: SHOULD be supported by all implementations, i.e., SHOULD NOT be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.
                - **Response**: REQUIRED in the response unless the query parameter `response_fields` is present and does not include this property.

            - **Example**:
                - As part of JSON response format: `"2007-04-05T14:30:20Z"` (i.e., encoded as an [RFC 3339 Internet Date/Time Format](https://tools.ietf.org/html/rfc3339#section-5.6) string.)
          format: date-time
          title: Last Modified
          type: string
      required:
        - last_modified
      title: EntryResourceAttributes
      type: object
    Error:
      description: An error response
      properties:
        code:
          description: an application-specific error code, expressed as a string value.
          title: Code
          type: string
        detail:
          description: A human-readable explanation specific to this occurrence of the problem.
          title: Detail
          type: string
        id:
          description: A unique identifier for this particular occurrence of the problem.
          title: Id
          type: string
        links:
          allOf:
            - $ref: "#/components/schemas/ErrorLinks"
          description: A links object storing about
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/Meta"
          description: a meta object containing non-standard meta-information about the error.
          title: Meta
        source:
          allOf:
            - $ref: "#/components/schemas/ErrorSource"
          description: An object containing references to the source of the error
          title: Source
        status:
          description: the HTTP status code applicable to this problem, expressed as a string value.
          title: Status
          type: string
        title:
          description: A short, human-readable summary of the problem. It **SHOULD NOT** change from occurrence to occurrence of the problem, except for purposes of localization.
          title: Title
          type: string
      title: Error
      type: object
    ErrorLinks:
      description: A Links object specific to Error objects
      properties:
        about:
          anyOf:
            - format: uri
              maxLength: 65536
              minLength: 1
              type: string
            - $ref: "#/components/schemas/Link"
          description: A link that leads to further details about this particular occurrence of the problem.
          title: About
      title: ErrorLinks
      type: object
    ErrorResponse:
      description: errors MUST be present and data MUST be skipped
      properties:
        data:
          anyOf:
            - $ref: "#/components/schemas/Resource"
            - items:
                $ref: "#/components/schemas/Resource"
              type: array
          description: Outputted Data
          title: Data
          uniqueItems: true
        errors:
          description: A list of OPTIMADE-specific JSON API error objects, where the field detail MUST be present.
          items:
            $ref: "#/components/schemas/OptimadeError"
          title: Errors
          type: array
          uniqueItems: true
        included:
          description: A list of unique included resources
          items:
            $ref: "#/components/schemas/Resource"
          title: Included
          type: array
          uniqueItems: true
        jsonapi:
          allOf:
            - $ref: "#/components/schemas/JsonApi"
          description: Information about the JSON API used
          title: Jsonapi
        links:
          allOf:
            - $ref: "#/components/schemas/ToplevelLinks"
          description: Links associated with the primary data or errors
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/ResponseMeta"
          description: A meta object containing non-standard information
          title: Meta
      required:
        - meta
        - errors
      title: ErrorResponse
      type: object
    ErrorSource:
      description: an object containing references to the source of the error
      properties:
        parameter:
          description: a string indicating which URI query parameter caused the error.
          title: Parameter
          type: string
        pointer:
          description: a JSON Pointer [RFC6901] to the associated entity in the request document [e.g. "/data" for a primary data object, or "/data/attributes/title" for a specific attribute].
          title: Pointer
          type: string
      title: ErrorSource
      type: object
    Implementation:
      description: Information on the server implementation
      properties:
        homepage:
          anyOf:
            - format: uri
              maxLength: 65536
              minLength: 1
              type: string
            - $ref: "#/components/schemas/Link"
          description: A [JSON API links object](http://jsonapi.org/format/1.0/#document-links) pointing to the homepage of the implementation.
          title: Homepage
        issue_tracker:
          anyOf:
            - format: uri
              maxLength: 65536
              minLength: 1
              type: string
            - $ref: "#/components/schemas/Link"
          description: A [JSON API links object](http://jsonapi.org/format/1.0/#document-links) pointing to the implementation's issue tracker.
          title: Issue Tracker
        maintainer:
          allOf:
            - $ref: "#/components/schemas/ImplementationMaintainer"
          description: A dictionary providing details about the maintainer of the implementation.
          title: Maintainer
        name:
          description: name of the implementation
          title: Name
          type: string
        source_url:
          anyOf:
            - format: uri
              maxLength: 65536
              minLength: 1
              type: string
            - $ref: "#/components/schemas/Link"
          description: A [JSON API links object](http://jsonapi.org/format/1.0/#document-links) pointing to the implementation source, either downloadable archive or version control system.
          title: Source Url
        version:
          description: version string of the current implementation
          title: Version
          type: string
      title: Implementation
      type: object
    ImplementationMaintainer:
      description: Details about the maintainer of the implementation
      properties:
        email:
          description: the maintainer's email address
          format: email
          title: Email
          type: string
      required:
        - email
      title: ImplementationMaintainer
      type: object
    InfoResponse:
      description: errors are not allowed
      properties:
        data:
          allOf:
            - $ref: "#/components/schemas/BaseInfoResource"
          description: The implementations /info data
          title: Data
        errors:
          description: A list of unique errors
          items:
            $ref: "#/components/schemas/Error"
          title: Errors
          type: array
          uniqueItems: true
        included:
          description: A list of unique included resources
          items:
            $ref: "#/components/schemas/Resource"
          title: Included
          type: array
          uniqueItems: true
        jsonapi:
          allOf:
            - $ref: "#/components/schemas/JsonApi"
          description: Information about the JSON API used
          title: Jsonapi
        links:
          allOf:
            - $ref: "#/components/schemas/ToplevelLinks"
          description: Links associated with the primary data or errors
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/ResponseMeta"
          description: A meta object containing non-standard information
          title: Meta
      required:
        - data
        - meta
      title: InfoResponse
      type: object
    JsonApi:
      description: An object describing the server's implementation
      properties:
        meta:
          allOf:
            - $ref: "#/components/schemas/Meta"
          description: Non-standard meta information
          title: Meta
        version:
          default: "1.0"
          description: Version of the json API used
          title: Version
          type: string
      title: JsonApi
      type: object
    Link:
      description: "A link **MUST** be represented as either: a string containing the link's URL or a link object."
      properties:
        href:
          description: a string containing the link’s URL.
          format: uri
          maxLength: 65536
          minLength: 1
          title: Href
          type: string
        meta:
          allOf:
            - $ref: "#/components/schemas/Meta"
          description: a meta object containing non-standard meta-information about the link.
          title: Meta
      required:
        - href
      title: Link
      type: object
    LinkType:
      description: Enumeration of link_type values
      enum:
        - child
        - root
        - external
        - providers
      title: LinkType
    LinksResource:
      description: A Links endpoint resource object
      properties:
        attributes:
          allOf:
            - $ref: "#/components/schemas/LinksResourceAttributes"
          description: A dictionary containing key-value pairs representing the Links resource's properties.
          title: Attributes
        id:
          description: |-
            An entry's ID as defined in section Definition of Terms.

            - **Type**: string.

            - **Requirements/Conventions**:
                - **Support**: MUST be supported by all implementations, MUST NOT be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.
                - **Response**: REQUIRED in the response.

            - **Examples**:
                - `"db/1234567"`
                - `"cod/2000000"`
                - `"cod/2000000@1234567"`
                - `"nomad/L1234567890"`
                - `"42"`
          title: Id
          type: string
        links:
          allOf:
            - $ref: "#/components/schemas/ResourceLinks"
          description: a links object containing links related to the resource.
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/Meta"
          description: a meta object containing non-standard meta-information about a resource that can not be represented as an attribute or relationship.
          title: Meta
        relationships:
          allOf:
            - $ref: "#/components/schemas/EntryRelationships"
          description: |-
            A dictionary containing references to other entries according to the description in section Relationships encoded as [JSON API Relationships](https://jsonapi.org/format/1.0/#document-resource-object-relationships).
            The OPTIONAL human-readable description of the relationship MAY be provided in the `description` field inside the `meta` dictionary of the JSON API resource identifier object.
          title: Relationships
        type:
          description: These objects are described in detail in the section Links Endpoint
          pattern: ^links$
          title: Type
          type: string
      required:
        - id
        - type
        - attributes
      title: LinksResource
      type: object
    LinksResourceAttributes:
      description: Links endpoint resource object attributes
      properties:
        aggregate:
          allOf:
            - $ref: "#/components/schemas/Aggregate"
          default: ok
          description: |-
            A string indicating whether a client that is following links to aggregate results from different OPTIMADE implementations should follow this link or not.
            This flag SHOULD NOT be indicated for links where `link_type` is not `child`.

            If not specified, clients MAY assume that the value is `ok`.
            If specified, and the value is anything different than `ok`, the client MUST assume that the server is suggesting not to follow the link during aggregation by default (also if the value is not among the known ones, in case a future specification adds new accepted values).

            Specific values indicate the reason why the server is providing the suggestion.
            A client MAY follow the link anyway if it has reason to do so (e.g., if the client is looking for all test databases, it MAY follow the links marked with `aggregate`=`test`).

            If specified, it MUST be one of the values listed in section Link Aggregate Options.
          title: Aggregate
        base_url:
          anyOf:
            - format: uri
              maxLength: 65536
              minLength: 1
              type: string
            - $ref: "#/components/schemas/Link"
          description: JSON API links object, pointing to the base URL for this implementation
          title: Base Url
        description:
          description: Human-readable description for the OPTIMADE API implementation, e.g., for use in clients to show a description to the end-user.
          title: Description
          type: string
        homepage:
          anyOf:
            - format: uri
              maxLength: 65536
              minLength: 1
              type: string
            - $ref: "#/components/schemas/Link"
          description: JSON API links object, pointing to a homepage URL for this implementation
          title: Homepage
        link_type:
          allOf:
            - $ref: "#/components/schemas/LinkType"
          description: |-
            The type of the linked relation.
            MUST be one of these values: 'child', 'root', 'external', 'providers'.
          title: Link Type
        name:
          description: Human-readable name for the OPTIMADE API implementation, e.g., for use in clients to show the name to the end-user.
          title: Name
          type: string
        no_aggregate_reason:
          description: |-
            An OPTIONAL human-readable string indicating the reason for suggesting not to aggregate results following the link.
            It SHOULD NOT be present if `aggregate`=`ok`.
          title: No Aggregate Reason
          type: string
      required:
        - name
        - description
        - base_url
        - homepage
        - link_type
      title: LinksResourceAttributes
      type: object
    LinksResponse:
      description: errors are not allowed
      properties:
        data:
          anyOf:
            - items:
                $ref: "#/components/schemas/LinksResource"
              type: array
            - items:
                type: object
              type: array
          description: List of unique OPTIMADE links resource objects
          title: Data
          uniqueItems: true
        errors:
          description: A list of unique errors
          items:
            $ref: "#/components/schemas/Error"
          title: Errors
          type: array
          uniqueItems: true
        included:
          anyOf:
            - items:
                $ref: "#/components/schemas/EntryResource"
              type: array
            - items:
                type: object
              type: array
          title: Included
          uniqueItems: true
        jsonapi:
          allOf:
            - $ref: "#/components/schemas/JsonApi"
          description: Information about the JSON API used
          title: Jsonapi
        links:
          allOf:
            - $ref: "#/components/schemas/ToplevelLinks"
          description: Links associated with the primary data or errors
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/ResponseMeta"
          description: A meta object containing non-standard information
          title: Meta
      required:
        - data
        - meta
      title: LinksResponse
      type: object
    Meta:
      description: Non-standard meta-information that can not be represented as an attribute or relationship.
      properties: {}
      title: Meta
      type: object
    OptimadeError:
      description: detail MUST be present
      properties:
        code:
          description: an application-specific error code, expressed as a string value.
          title: Code
          type: string
        detail:
          description: A human-readable explanation specific to this occurrence of the problem.
          title: Detail
          type: string
        id:
          description: A unique identifier for this particular occurrence of the problem.
          title: Id
          type: string
        links:
          allOf:
            - $ref: "#/components/schemas/ErrorLinks"
          description: A links object storing about
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/Meta"
          description: a meta object containing non-standard meta-information about the error.
          title: Meta
        source:
          allOf:
            - $ref: "#/components/schemas/ErrorSource"
          description: An object containing references to the source of the error
          title: Source
        status:
          description: the HTTP status code applicable to this problem, expressed as a string value.
          title: Status
          type: string
        title:
          description: A short, human-readable summary of the problem. It **SHOULD NOT** change from occurrence to occurrence of the problem, except for purposes of localization.
          title: Title
          type: string
      required:
        - detail
      title: OptimadeError
      type: object
    Periodicity:
      description: Integer enumeration of dimension_types values
      enum:
        - 0
        - 1
      title: Periodicity
      type: integer
    Person:
      description: A person, i.e., an author, editor or other.
      properties:
        firstname:
          description: First name of the person.
          title: Firstname
          type: string
        lastname:
          description: Last name of the person.
          title: Lastname
          type: string
        name:
          description: Full name of the person, REQUIRED.
          title: Name
          type: string
      required:
        - name
      title: Person
      type: object
    Provider:
      description: Information on the database provider of the implementation.
      properties:
        description:
          description: a longer description of the database provider
          title: Description
          type: string
        homepage:
          anyOf:
            - format: uri
              maxLength: 65536
              minLength: 1
              type: string
            - $ref: "#/components/schemas/Link"
          description: a [JSON API links object](http://jsonapi.org/format/1.0#document-links) pointing to homepage of the database provider, either directly as a string, or as a link object.
          title: Homepage
        name:
          description: a short name for the database provider
          title: Name
          type: string
        prefix:
          description: database-provider-specific prefix as found in section Database-Provider-Specific Namespace Prefixes.
          pattern: ^[a-z]([a-z]|[0-9]|_)*$
          title: Prefix
          type: string
      required:
        - name
        - description
        - prefix
      title: Provider
      type: object
    ReferenceRelationship:
      description: Similar to normal JSON API relationship, but with addition of OPTIONAL meta field for a resource
      properties:
        data:
          anyOf:
            - $ref: "#/components/schemas/BaseRelationshipResource"
            - items:
                $ref: "#/components/schemas/BaseRelationshipResource"
              type: array
          description: Resource linkage
          title: Data
          uniqueItems: true
        links:
          allOf:
            - $ref: "#/components/schemas/RelationshipLinks"
          description: "a links object containing at least one of the following: self, related"
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/Meta"
          description: a meta object that contains non-standard meta-information about the relationship.
          title: Meta
      title: ReferenceRelationship
      type: object
    ReferenceResource:
      description: |-
        The `references` entries describe bibliographic references.

        The following properties are used to provide the bibliographic details:

        - **address**, **annote**, **booktitle**, **chapter**, **crossref**, **edition**, **howpublished**, **institution**, **journal**, **key**, **month**, **note**, **number**, **organization**, **pages**, **publisher**, **school**, **series**, **title**, **volume**, **year**: meanings of these properties match the [BibTeX specification](http://bibtexml.sourceforge.net/btxdoc.pdf), values are strings;
        - **bib_type**: type of the reference, corresponding to **type** property in the BibTeX specification, value is string;
        - **authors** and **editors**: lists of *person objects* which are dictionaries with the following keys:
            - **name**: Full name of the person, REQUIRED.
            - **firstname**, **lastname**: Parts of the person's name, OPTIONAL.
        - **doi** and **url**: values are strings.
        - **Requirements/Conventions**:
            - **Support**: OPTIONAL support in implementations, i.e., any of the properties MAY be `null`.
            - **Query**: Support for queries on any of these properties is OPTIONAL.
                If supported, filters MAY support only a subset of comparison operators.
            - Every references entry MUST contain at least one of the properties.
      properties:
        attributes:
          $ref: "#/components/schemas/ReferenceResourceAttributes"
        id:
          description: |-
            An entry's ID as defined in section Definition of Terms.

            - **Type**: string.

            - **Requirements/Conventions**:
                - **Support**: MUST be supported by all implementations, MUST NOT be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.
                - **Response**: REQUIRED in the response.

            - **Examples**:
                - `"db/1234567"`
                - `"cod/2000000"`
                - `"cod/2000000@1234567"`
                - `"nomad/L1234567890"`
                - `"42"`
          title: Id
          type: string
        links:
          allOf:
            - $ref: "#/components/schemas/ResourceLinks"
          description: a links object containing links related to the resource.
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/Meta"
          description: a meta object containing non-standard meta-information about a resource that can not be represented as an attribute or relationship.
          title: Meta
        relationships:
          allOf:
            - $ref: "#/components/schemas/EntryRelationships"
          description: |-
            A dictionary containing references to other entries according to the description in section Relationships encoded as [JSON API Relationships](https://jsonapi.org/format/1.0/#document-resource-object-relationships).
            The OPTIONAL human-readable description of the relationship MAY be provided in the `description` field inside the `meta` dictionary of the JSON API resource identifier object.
          title: Relationships
        type:
          description: |-
            The name of the type of an entry.
            - **Type**: string.
            - **Requirements/Conventions**:
                - **Support**: MUST be supported by all implementations, MUST NOT be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.
                - **Response**: REQUIRED in the response.
                - MUST be an existing entry type.
                - The entry of type <type> and ID <id> MUST be returned in response to a request for `/<type>/<id>` under the versioned base URL.
            - **Example**: `"structures"`
          pattern: ^references$
          title: Type
          type: string
      required:
        - id
        - type
        - attributes
      title: ReferenceResource
      type: object
    ReferenceResourceAttributes:
      description: |-
        Model that stores the attributes of a reference.

        Many properties match the meaning described in the
        [BibTeX specification](http://bibtexml.sourceforge.net/btxdoc.pdf).
      properties:
        address:
          description: Meaning of property matches the BiBTeX specification.
          title: Address
          type: string
        annote:
          description: Meaning of property matches the BiBTeX specification.
          title: Annote
          type: string
        authors:
          description: List of person objects containing the authors of the reference.
          items:
            $ref: "#/components/schemas/Person"
          title: Authors
          type: array
        bib_type:
          description: Type of the reference, corresponding to the **type** property in the BiBTeX specification.
          title: Bib Type
          type: string
        booktitle:
          description: Meaning of property matches the BiBTeX specification.
          title: Booktitle
          type: string
        chapter:
          description: Meaning of property matches the BiBTeX specification.
          title: Chapter
          type: string
        crossref:
          description: Meaning of property matches the BiBTeX specification.
          title: Crossref
          type: string
        doi:
          description: The digital object identifier of the reference.
          title: Doi
          type: string
        edition:
          description: Meaning of property matches the BiBTeX specification.
          title: Edition
          type: string
        editors:
          description: List of person objects containing the editors of the reference.
          items:
            $ref: "#/components/schemas/Person"
          title: Editors
          type: array
        howpublished:
          description: Meaning of property matches the BiBTeX specification.
          title: Howpublished
          type: string
        immutable_id:
          description: |-
            The entry's immutable ID (e.g., an UUID). This is important for databases having preferred IDs that point to "the latest version" of a record, but still offer access to older variants. This ID maps to the version-specific record, in case it changes in the future.

            - **Type**: string.

            - **Requirements/Conventions**:
                - **Support**: OPTIONAL support in implementations, i.e., MAY be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.

            - **Examples**:
                - `"8bd3e750-b477-41a0-9b11-3a799f21b44f"`
                - `"fjeiwoj,54;@=%<>#32"` (Strings that are not URL-safe are allowed.)
          title: Immutable Id
          type: string
        institution:
          description: Meaning of property matches the BiBTeX specification.
          title: Institution
          type: string
        journal:
          description: Meaning of property matches the BiBTeX specification.
          title: Journal
          type: string
        key:
          description: Meaning of property matches the BiBTeX specification.
          title: Key
          type: string
        last_modified:
          description: |-
            Date and time representing when the entry was last modified.

            - **Type**: timestamp.

            - **Requirements/Conventions**:
                - **Support**: SHOULD be supported by all implementations, i.e., SHOULD NOT be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.
                - **Response**: REQUIRED in the response unless the query parameter `response_fields` is present and does not include this property.

            - **Example**:
                - As part of JSON response format: `"2007-04-05T14:30:20Z"` (i.e., encoded as an [RFC 3339 Internet Date/Time Format](https://tools.ietf.org/html/rfc3339#section-5.6) string.)
          format: date-time
          title: Last Modified
          type: string
        month:
          description: Meaning of property matches the BiBTeX specification.
          title: Month
          type: string
        note:
          description: Meaning of property matches the BiBTeX specification.
          title: Note
          type: string
        number:
          description: Meaning of property matches the BiBTeX specification.
          title: Number
          type: string
        organization:
          description: Meaning of property matches the BiBTeX specification.
          title: Organization
          type: string
        pages:
          description: Meaning of property matches the BiBTeX specification.
          title: Pages
          type: string
        publisher:
          description: Meaning of property matches the BiBTeX specification.
          title: Publisher
          type: string
        school:
          description: Meaning of property matches the BiBTeX specification.
          title: School
          type: string
        series:
          description: Meaning of property matches the BiBTeX specification.
          title: Series
          type: string
        title:
          description: Meaning of property matches the BiBTeX specification.
          title: Title
          type: string
        url:
          description: The URL of the reference.
          format: uri
          maxLength: 65536
          minLength: 1
          title: Url
          type: string
        volume:
          description: Meaning of property matches the BiBTeX specification.
          title: Volume
          type: string
        year:
          description: Meaning of property matches the BiBTeX specification.
          title: Year
          type: string
      required:
        - last_modified
      title: ReferenceResourceAttributes
      type: object
    ReferenceResponseMany:
      description: errors are not allowed
      properties:
        data:
          anyOf:
            - items:
                $ref: "#/components/schemas/ReferenceResource"
              type: array
            - items:
                type: object
              type: array
          description: List of unique OPTIMADE references entry resource objects
          title: Data
          uniqueItems: true
        errors:
          description: A list of unique errors
          items:
            $ref: "#/components/schemas/Error"
          title: Errors
          type: array
          uniqueItems: true
        included:
          anyOf:
            - items:
                $ref: "#/components/schemas/EntryResource"
              type: array
            - items:
                type: object
              type: array
          title: Included
          uniqueItems: true
        jsonapi:
          allOf:
            - $ref: "#/components/schemas/JsonApi"
          description: Information about the JSON API used
          title: Jsonapi
        links:
          allOf:
            - $ref: "#/components/schemas/ToplevelLinks"
          description: Links associated with the primary data or errors
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/ResponseMeta"
          description: A meta object containing non-standard information
          title: Meta
      required:
        - data
        - meta
      title: ReferenceResponseMany
      type: object
    ReferenceResponseOne:
      description: errors are not allowed
      properties:
        data:
          anyOf:
            - $ref: "#/components/schemas/ReferenceResource"
            - type: object
          description: A single references entry resource
          title: Data
        errors:
          description: A list of unique errors
          items:
            $ref: "#/components/schemas/Error"
          title: Errors
          type: array
          uniqueItems: true
        included:
          anyOf:
            - items:
                $ref: "#/components/schemas/EntryResource"
              type: array
            - items:
                type: object
              type: array
          title: Included
          uniqueItems: true
        jsonapi:
          allOf:
            - $ref: "#/components/schemas/JsonApi"
          description: Information about the JSON API used
          title: Jsonapi
        links:
          allOf:
            - $ref: "#/components/schemas/ToplevelLinks"
          description: Links associated with the primary data or errors
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/ResponseMeta"
          description: A meta object containing non-standard information
          title: Meta
      required:
        - data
        - meta
      title: ReferenceResponseOne
      type: object
    RelationshipLinks:
      description: |-
        A resource object **MAY** contain references to other resource objects ("relationships").
        Relationships may be to-one or to-many.
        Relationships can be specified by including a member in a resource's links object.
      properties:
        related:
          anyOf:
            - format: uri
              maxLength: 65536
              minLength: 1
              type: string
            - $ref: "#/components/schemas/Link"
          description: A [related resource link](https://jsonapi.org/format/1.0/#document-resource-object-related-resource-links).
          title: Related
        self:
          anyOf:
            - format: uri
              maxLength: 65536
              minLength: 1
              type: string
            - $ref: "#/components/schemas/Link"
          description: |-
            A link for the relationship itself (a 'relationship link').
            This link allows the client to directly manipulate the relationship.
            When fetched successfully, this link returns the [linkage](https://jsonapi.org/format/1.0/#document-resource-object-linkage) for the related resources as its primary data.
            (See [Fetching Relationships](https://jsonapi.org/format/1.0/#fetching-relationships).)
          title: Self
      title: RelationshipLinks
      type: object
    Relationships:
      description: |-
        Members of the relationships object ("relationships") represent references from the resource object in which it's defined to other resource objects.
        Keys MUST NOT be:
            type
            id
      properties: {}
      title: Relationships
      type: object
    Resource:
      description: Resource objects appear in a JSON API document to represent resources.
      properties:
        attributes:
          allOf:
            - $ref: "#/components/schemas/Attributes"
          description: an attributes object representing some of the resource’s data.
          title: Attributes
        id:
          description: Resource ID
          title: Id
          type: string
        links:
          allOf:
            - $ref: "#/components/schemas/ResourceLinks"
          description: a links object containing links related to the resource.
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/Meta"
          description: a meta object containing non-standard meta-information about a resource that can not be represented as an attribute or relationship.
          title: Meta
        relationships:
          allOf:
            - $ref: "#/components/schemas/Relationships"
          description: |-
            [Relationships object](https://jsonapi.org/format/1.0/#document-resource-object-relationships)
            describing relationships between the resource and other JSON API resources.
          title: Relationships
        type:
          description: Resource type
          title: Type
          type: string
      required:
        - id
        - type
      title: Resource
      type: object
    ResourceLinks:
      description: A Resource Links object
      properties:
        self:
          anyOf:
            - format: uri
              maxLength: 65536
              minLength: 1
              type: string
            - $ref: "#/components/schemas/Link"
          description: A link that identifies the resource represented by the resource object.
          title: Self
      title: ResourceLinks
      type: object
    ResponseMeta:
      description: |-
        A [JSON API meta member](https://jsonapi.org/format/1.0#document-meta)
        that contains JSON API meta objects of non-standard
        meta-information.

        OPTIONAL additional information global to the query that is not
        specified in this document, MUST start with a
        database-provider-specific prefix.
      properties:
        api_version:
          description: |-
            Presently used full version of the OPTIMADE API.
            The version number string MUST NOT be prefixed by, e.g., "v".
            Examples: `1.0.0`, `1.0.0-rc.2`.
          pattern: ^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-((?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)(?:\.(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*))?(?:\+([0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?$
          title: Api Version
          type: string
        data_available:
          description: An integer containing the total number of data resource objects available in the database for the endpoint.
          title: Data Available
          type: integer
        data_returned:
          description: An integer containing the total number of data resource objects returned for the current `filter` query, independent of pagination.
          minimum: 0
          title: Data Returned
          type: integer
        implementation:
          allOf:
            - $ref: "#/components/schemas/Implementation"
          description: a dictionary describing the server implementation
          title: Implementation
        last_id:
          description: a string containing the last ID returned
          title: Last Id
          type: string
        more_data_available:
          description: "`false` if the response contains all data for the request (e.g., a request issued to a single entry endpoint, or a `filter` query at the last page of a paginated response) and `true` if the response is incomplete in the sense that multiple objects match the request, and not all of them have been included in the response (e.g., a query with multiple pages that is not at the last page)."
          title: More Data Available
          type: boolean
        provider:
          allOf:
            - $ref: "#/components/schemas/Provider"
          description: information on the database provider of the implementation.
          title: Provider
        query:
          allOf:
            - $ref: "#/components/schemas/ResponseMetaQuery"
          description: Information on the Query that was requested
          title: Query
        response_message:
          description: response string from the server
          title: Response Message
          type: string
        schema:
          anyOf:
            - format: uri
              maxLength: 65536
              minLength: 1
              type: string
            - $ref: "#/components/schemas/Link"
          description: |-
            A [JSON API links object](http://jsonapi.org/format/1.0/#document-links) that points to a schema for the response.
            If it is a string, or a dictionary containing no `meta` field, the provided URL MUST point at an [OpenAPI](https://swagger.io/specification/) schema.
            It is possible that future versions of this specification allows for alternative schema types.
            Hence, if the `meta` field of the JSON API links object is provided and contains a field `schema_type` that is not equal to the string `OpenAPI` the client MUST not handle failures to parse the schema or to validate the response against the schema as errors.
          title: Schema
        time_stamp:
          description: A timestamp containing the date and time at which the query was executed.
          format: date-time
          title: Time Stamp
          type: string
        warnings:
          description: |-
            A list of warning resource objects representing non-critical errors or warnings.
            A warning resource object is defined similarly to a [JSON API error object](http://jsonapi.org/format/1.0/#error-objects), but MUST also include the field `type`, which MUST have the value `"warning"`.
            The field `detail` MUST be present and SHOULD contain a non-critical message, e.g., reporting unrecognized search attributes or deprecated features.
            The field `status`, representing a HTTP response status code, MUST NOT be present for a warning resource object.
            This is an exclusive field for error resource objects.
          items:
            $ref: "#/components/schemas/Warnings"
          title: Warnings
          type: array
          uniqueItems: true
      required:
        - query
        - api_version
        - more_data_available
      title: ResponseMeta
      type: object
    ResponseMetaQuery:
      description: Information on the query that was requested.
      properties:
        representation:
          description: |-
            A string with the part of the URL following the versioned or unversioned base URL that serves the API.
            Query parameters that have not been used in processing the request MAY be omitted.
            In particular, if no query parameters have been involved in processing the request, the query part of the URL MAY be excluded.
            Example: `/structures?filter=nelements=2`
          title: Representation
          type: string
      required:
        - representation
      title: ResponseMetaQuery
      type: object
    Species:
      description: |-
        A list describing the species of the sites of this structure.

        Species can represent pure chemical elements, virtual-crystal atoms representing a
        statistical occupation of a given site by multiple chemical elements, and/or a
        location to which there are attached atoms, i.e., atoms whose precise location are
        unknown beyond that they are attached to that position (frequently used to indicate
        hydrogen atoms attached to another element, e.g., a carbon with three attached
        hydrogens might represent a methyl group, -CH3).

        - **Examples**:
            - `[ {"name": "Ti", "chemical_symbols": ["Ti"], "concentration": [1.0]} ]`: any site with this species is occupied by a Ti atom.
            - `[ {"name": "Ti", "chemical_symbols": ["Ti", "vacancy"], "concentration": [0.9, 0.1]} ]`: any site with this species is occupied by a Ti atom with 90 % probability, and has a vacancy with 10 % probability.
            - `[ {"name": "BaCa", "chemical_symbols": ["vacancy", "Ba", "Ca"], "concentration": [0.05, 0.45, 0.5], "mass": [0.0, 137.327, 40.078]} ]`: any site with this species is occupied by a Ba atom with 45 % probability, a Ca atom with 50 % probability, and by a vacancy with 5 % probability. The mass of this site is (on average) 88.5 a.m.u.
            - `[ {"name": "C12", "chemical_symbols": ["C"], "concentration": [1.0], "mass": [12.0]} ]`: any site with this species is occupied by a carbon isotope with mass 12.
            - `[ {"name": "C13", "chemical_symbols": ["C"], "concentration": [1.0], "mass": [13.0]} ]`: any site with this species is occupied by a carbon isotope with mass 13.
            - `[ {"name": "CH3", "chemical_symbols": ["C"], "concentration": [1.0], "attached": ["H"], "nattached": [3]} ]`: any site with this species is occupied by a methyl group, -CH3, which is represented without specifying precise positions of the hydrogen atoms.
      properties:
        attached:
          description: If provided MUST be a list of length 1 or more of strings of chemical symbols for the elements attached to this site, or "X" for a non-chemical element.
          items:
            type: string
          title: Attached
          type: array
        chemical_symbols:
          description: |-
            MUST be a list of strings of all chemical elements composing this species. Each item of the list MUST be one of the following:

            - a valid chemical-element name, or
            - the special value `"X"` to represent a non-chemical element, or
            - the special value `"vacancy"` to represent that this site has a non-zero probability of having a vacancy (the respective probability is indicated in the `concentration` list, see below).

            If any one entry in the `species` list has a `chemical_symbols` list that is longer than 1 element, the correct flag MUST be set in the list `structure_features`.
          items:
            type: string
          title: Chemical Symbols
          type: array
        concentration:
          description: |-
            MUST be a list of floats, with same length as `chemical_symbols`. The numbers represent the relative concentration of the corresponding chemical symbol in this species. The numbers SHOULD sum to one. Cases in which the numbers do not sum to one typically fall only in the following two categories:

            - Numerical errors when representing float numbers in fixed precision, e.g. for two chemical symbols with concentrations `1/3` and `2/3`, the concentration might look something like `[0.33333333333, 0.66666666666]`. If the client is aware that the sum is not one because of numerical precision, it can renormalize the values so that the sum is exactly one.
            - Experimental errors in the data present in the database. In this case, it is the responsibility of the client to decide how to process the data.

            Note that concentrations are uncorrelated between different site (even of the same species).
          items:
            type: number
          title: Concentration
          type: array
        mass:
          description: |-
            If present MUST be a list of floats expressed in a.m.u.
            Elements denoting vacancies MUST have masses equal to 0.
          items:
            type: number
          title: Mass
          type: array
        name:
          description: Gives the name of the species; the **name** value MUST be unique in the `species` list.
          title: Name
          type: string
        nattached:
          description: If provided MUST be a list of length 1 or more of integers indicating the number of attached atoms of the kind specified in the value of the :field:`attached` key.
          items:
            type: integer
          title: Nattached
          type: array
        original_name:
          description: |-
            Can be any valid Unicode string, and SHOULD contain (if specified) the name of the species that is used internally in the source database.

            Note: With regards to "source database", we refer to the immediate source being queried via the OPTIMADE API implementation.
          title: Original Name
          type: string
      required:
        - name
        - chemical_symbols
        - concentration
      title: Species
      type: object
    StructureFeatures:
      description: Enumeration of structure_features values
      enum:
        - disorder
        - implicit_atoms
        - site_attachments
        - assemblies
      title: StructureFeatures
    StructureRelationship:
      description: Similar to normal JSON API relationship, but with addition of OPTIONAL meta field for a resource
      properties:
        data:
          anyOf:
            - $ref: "#/components/schemas/BaseRelationshipResource"
            - items:
                $ref: "#/components/schemas/BaseRelationshipResource"
              type: array
          description: Resource linkage
          title: Data
          uniqueItems: true
        links:
          allOf:
            - $ref: "#/components/schemas/RelationshipLinks"
          description: "a links object containing at least one of the following: self, related"
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/Meta"
          description: a meta object that contains non-standard meta-information about the relationship.
          title: Meta
      title: StructureRelationship
      type: object
    StructureResource:
      description: Representing a structure.
      properties:
        attributes:
          $ref: "#/components/schemas/StructureResourceAttributes"
        id:
          description: |-
            An entry's ID as defined in section Definition of Terms.

            - **Type**: string.

            - **Requirements/Conventions**:
                - **Support**: MUST be supported by all implementations, MUST NOT be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.
                - **Response**: REQUIRED in the response.

            - **Examples**:
                - `"db/1234567"`
                - `"cod/2000000"`
                - `"cod/2000000@1234567"`
                - `"nomad/L1234567890"`
                - `"42"`
          title: Id
          type: string
        links:
          allOf:
            - $ref: "#/components/schemas/ResourceLinks"
          description: a links object containing links related to the resource.
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/Meta"
          description: a meta object containing non-standard meta-information about a resource that can not be represented as an attribute or relationship.
          title: Meta
        relationships:
          allOf:
            - $ref: "#/components/schemas/EntryRelationships"
          description: |-
            A dictionary containing references to other entries according to the description in section Relationships encoded as [JSON API Relationships](https://jsonapi.org/format/1.0/#document-resource-object-relationships).
            The OPTIONAL human-readable description of the relationship MAY be provided in the `description` field inside the `meta` dictionary of the JSON API resource identifier object.
          title: Relationships
        type:
          description: |-
            The name of the type of an entry.

            - **Type**: string.

            - **Requirements/Conventions**:
                - **Support**: MUST be supported by all implementations, MUST NOT be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.
                - **Response**: REQUIRED in the response.
                - MUST be an existing entry type.
                - The entry of type `<type>` and ID `<id>` MUST be returned in response to a request for `/<type>/<id>` under the versioned base URL.

            - **Examples**:
                - `"structures"`
          pattern: ^structures$
          title: Type
          type: string
      required:
        - id
        - type
        - attributes
      title: StructureResource
      type: object
    StructureResourceAttributes:
      description: This class contains the Field for the attributes used to represent a structure, e.g. unit cell, atoms, positions.
      properties:
        assemblies:
          description: |-
            A description of groups of sites that are statistically correlated.

            - **Type**: list of dictionary with keys:
                - `sites_in_groups`: list of list of integers (REQUIRED)
                - `group_probabilities`: list of floats (REQUIRED)

            - **Requirements/Conventions**:
                - **Support**: OPTIONAL support in implementations, i.e., MAY be `null`.
                - **Query**: Support for queries on this property is OPTIONAL.
                    If supported, filters MAY support only a subset of comparison operators.
                - The property SHOULD be `null` for entries that have no partial occupancies.
                - If present, the correct flag MUST be set in the list `structure_features`.
                - Client implementations MUST check its presence (as its presence changes the interpretation of the structure).
                - If present, it MUST be a list of dictionaries, each of which represents an assembly and MUST have the following two keys:
                    - **sites_in_groups**: Index of the sites (0-based) that belong to each group for each assembly.

                        Example: `[[1], [2]]`: two groups, one with the second site, one with the third.
                        Example: `[[1,2], [3]]`: one group with the second and third site, one with the fourth.

                    - **group_probabilities**: Statistical probability of each group. It MUST have the same length as `sites_in_groups`.
                        It SHOULD sum to one.
                        See below for examples of how to specify the probability of the occurrence of a vacancy.
                        The possible reasons for the values not to sum to one are the same as already specified above for the `concentration` of each `species`.

                - If a site is not present in any group, it means that it is present with 100 % probability (as if no assembly was specified).
                - A site MUST NOT appear in more than one group.

            - **Examples** (for each entry of the assemblies list):
                - `{"sites_in_groups": [[0], [1]], "group_probabilities: [0.3, 0.7]}`: the first site and the second site never occur at the same time in the unit cell.
                    Statistically, 30 % of the times the first site is present, while 70 % of the times the second site is present.
                - `{"sites_in_groups": [[1,2], [3]], "group_probabilities: [0.3, 0.7]}`: the second and third site are either present together or not present; they form the first group of atoms for this assembly.
                    The second group is formed by the fourth site.
                    Sites of the first group (the second and the third) are never present at the same time as the fourth site.
                    30 % of times sites 1 and 2 are present (and site 3 is absent); 70 % of times site 3 is present (and sites 1 and 2 are absent).

            - **Notes**:
                - Assemblies are essential to represent, for instance, the situation where an atom can statistically occupy two different positions (sites).

                - By defining groups, it is possible to represent, e.g., the case where a functional molecule (and not just one atom) is either present or absent (or the case where it it is present in two conformations)

                - Considerations on virtual alloys and on vacancies: In the special case of a virtual alloy, these specifications allow two different, equivalent ways of specifying them.
                    For instance, for a site at the origin with 30 % probability of being occupied by Si, 50 % probability of being occupied by Ge, and 20 % of being a vacancy, the following two representations are possible:

                    - Using a single species:
                        ```json
                        {
                          "cartesian_site_positions": [[0,0,0]],
                          "species_at_sites": ["SiGe-vac"],
                          "species": [
                          {
                            "name": "SiGe-vac",
                            "chemical_symbols": ["Si", "Ge", "vacancy"],
                            "concentration": [0.3, 0.5, 0.2]
                          }
                          ]
                          // ...
                        }
                        ```

                    - Using multiple species and the assemblies:
                        ```json
                        {
                          "cartesian_site_positions": [ [0,0,0], [0,0,0], [0,0,0] ],
                          "species_at_sites": ["Si", "Ge", "vac"],
                          "species": [
                            { "name": "Si", "chemical_symbols": ["Si"], "concentration": [1.0] },
                            { "name": "Ge", "chemical_symbols": ["Ge"], "concentration": [1.0] },
                            { "name": "vac", "chemical_symbols": ["vacancy"], "concentration": [1.0] }
                          ],
                          "assemblies": [
                            {
                          "sites_in_groups": [ [0], [1], [2] ],
                          "group_probabilities": [0.3, 0.5, 0.2]
                            }
                          ]
                          // ...
                        }
                        ```

                - It is up to the database provider to decide which representation to use, typically depending on the internal format in which the structure is stored.
                    However, given a structure identified by a unique ID, the API implementation MUST always provide the same representation for it.

                - The probabilities of occurrence of different assemblies are uncorrelated.
                    So, for instance in the following case with two assemblies:
                    ```json
                    {
                      "assemblies": [
                        {
                          "sites_in_groups": [ [0], [1] ],
                          "group_probabilities": [0.2, 0.8],
                        },
                        {
                          "sites_in_groups": [ [2], [3] ],
                          "group_probabilities": [0.3, 0.7]
                        }
                      ]
                    }
                    ```

                    Site 0 is present with a probability of 20 % and site 1 with a probability of 80 %. These two sites are correlated (either site 0 or 1 is present). Similarly, site 2 is present with a probability of 30 % and site 3 with a probability of 70 %.
                    These two sites are correlated (either site 2 or 3 is present).
                    However, the presence or absence of sites 0 and 1 is not correlated with the presence or absence of sites 2 and 3 (in the specific example, the pair of sites (0, 2) can occur with 0.2*0.3 = 6 % probability; the pair (0, 3) with 0.2*0.7 = 14 % probability; the pair (1, 2) with 0.8*0.3 = 24 % probability; and the pair (1, 3) with 0.8*0.7 = 56 % probability).
          items:
            $ref: "#/components/schemas/Assembly"
          title: Assemblies
          type: array
        cartesian_site_positions:
          description: |-
            Cartesian positions of each site in the structure.
            A site is usually used to describe positions of atoms; what atoms can be encountered at a given site is conveyed by the `species_at_sites` property, and the species themselves are described in the `species` property.

            - **Type**: list of list of floats

            - **Requirements/Conventions**:
                - **Support**: SHOULD be supported by all implementations, i.e., SHOULD NOT be `null`.
                - **Query**: Support for queries on this property is OPTIONAL.
                  If supported, filters MAY support only a subset of comparison operators.
                - It MUST be a list of length equal to the number of sites in the structure, where every element is a list of the three Cartesian coordinates of a site expressed as float values in the unit angstrom (Å).
                - An entry MAY have multiple sites at the same Cartesian position (for a relevant use of this, see e.g., the property `assemblies`).

            - **Examples**:
                - `[[0,0,0],[0,0,2]]` indicates a structure with two sites, one sitting at the origin and one along the (positive) *z*-axis, 2 Å away from the origin.
          items:
            items:
              type: number
            maxItems: 3
            minItems: 3
            type: array
          nullable: true
          title: Cartesian Site Positions
          type: array
        chemical_formula_anonymous:
          description: |-
            The anonymous formula is the `chemical_formula_reduced`, but where the elements are instead first ordered by their chemical proportion number, and then, in order left to right, replaced by anonymous symbols A, B, C, ..., Z, Aa, Ba, ..., Za, Ab, Bb, ... and so on.

            - **Type**: string

            - **Requirements/Conventions**:
                - **Support**: SHOULD be supported by all implementations, i.e., SHOULD NOT be `null`.
                - **Query**: MUST be a queryable property.
                  However, support for filters using partial string matching with this property is OPTIONAL (i.e., BEGINS WITH, ENDS WITH, and CONTAINS).

            - **Examples**:
                - `"A2B"`
                - `"A42B42C16D12E10F9G5"`

            - **Querying**:
                - A filter that matches an exactly given formula is `chemical_formula_anonymous="A2B"`.
          nullable: true
          pattern: ^([A-Z][a-z]?\d*)*$
          title: Chemical Formula Anonymous
          type: string
        chemical_formula_descriptive:
          description: |-
            The chemical formula for a structure as a string in a form chosen by the API implementation.

            - **Type**: string

            - **Requirements/Conventions**:
                - **Support**: SHOULD be supported by all implementations, i.e., SHOULD NOT be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.
                - The chemical formula is given as a string consisting of properly capitalized element symbols followed by integers or decimal numbers, balanced parentheses, square, and curly brackets `(`,`)`, `[`,`]`, `{`, `}`, commas, the `+`, `-`, `:` and `=` symbols. The parentheses are allowed to be followed by a number. Spaces are allowed anywhere except within chemical symbols. The order of elements and any groupings indicated by parentheses or brackets are chosen freely by the API implementation.
                - The string SHOULD be arithmetically consistent with the element ratios in the `chemical_formula_reduced` property.
                - It is RECOMMENDED, but not mandatory, that symbols, parentheses and brackets, if used, are used with the meanings prescribed by [IUPAC's Nomenclature of Organic Chemistry](https://www.qmul.ac.uk/sbcs/iupac/bibliog/blue.html).

            - **Examples**:
                - `"(H2O)2 Na"`
                - `"NaCl"`
                - `"CaCO3"`
                - `"CCaO3"`
                - `"(CH3)3N+ - [CH2]2-OH = Me3N+ - CH2 - CH2OH"`

            - **Query examples**:
                - Note: the free-form nature of this property is likely to make queries on it across different databases inconsistent.
                - A filter that matches an exactly given formula: `chemical_formula_descriptive="(H2O)2 Na"`.
                - A filter that does a partial match: `chemical_formula_descriptive CONTAINS "H2O"`.
          nullable: true
          title: Chemical Formula Descriptive
          type: string
        chemical_formula_hill:
          description: |-
            The chemical formula for a structure in [Hill form](https://dx.doi.org/10.1021/ja02046a005) with element symbols followed by integer chemical proportion numbers. The proportion number MUST be omitted if it is 1.

            - **Type**: string

            - **Requirements/Conventions**:
                - **Support**: OPTIONAL support in implementations, i.e., MAY be `null`.
                - **Query**: Support for queries on this property is OPTIONAL.
                  If supported, only a subset of the filter features MAY be supported.
                - The overall scale factor of the chemical proportions is chosen such that the resulting values are integers that indicate the most chemically relevant unit of which the system is composed.
                  For example, if the structure is a repeating unit cell with four hydrogens and four oxygens that represents two hydroperoxide molecules, `chemical_formula_hill` is `"H2O2"` (i.e., not `"HO"`, nor `"H4O4"`).
                - If the chemical insight needed to ascribe a Hill formula to the system is not present, the property MUST be handled as unset.
                - Element symbols MUST have proper capitalization (e.g., `"Si"`, not `"SI"` for "silicon").
                - Elements MUST be placed in [Hill order](https://dx.doi.org/10.1021/ja02046a005), followed by their integer chemical proportion number.
                  Hill order means: if carbon is present, it is placed first, and if also present, hydrogen is placed second.
                  After that, all other elements are ordered alphabetically.
                  If carbon is not present, all elements are ordered alphabetically.
                - If the system has sites with partial occupation and the total occupations of each element do not all sum up to integers, then the Hill formula SHOULD be handled as unset.
                - No spaces or separators are allowed.

            - **Examples**:
                - `"H2O2"`

            - **Query examples**:
                - A filter that matches an exactly given formula is `chemical_formula_hill="H2O2"`.
          pattern: ^([A-Z][a-z]?\d*)*$
          title: Chemical Formula Hill
          type: string
        chemical_formula_reduced:
          description: |-
            The reduced chemical formula for a structure as a string with element symbols and integer chemical proportion numbers.
            The proportion number MUST be omitted if it is 1.

            - **Type**: string

            - **Requirements/Conventions**:
                - **Support**: SHOULD be supported by all implementations, i.e., SHOULD NOT be `null`.
                - **Query**: MUST be a queryable property.
                  However, support for filters using partial string matching with this property is OPTIONAL (i.e., BEGINS WITH, ENDS WITH, and CONTAINS).
                  Intricate queries on formula components are instead suggested to be formulated using set-type filter operators on the multi valued `elements` and `elements_ratios` properties.
                - Element symbols MUST have proper capitalization (e.g., `"Si"`, not `"SI"` for "silicon").
                - Elements MUST be placed in alphabetical order, followed by their integer chemical proportion number.
                - For structures with no partial occupation, the chemical proportion numbers are the smallest integers for which the chemical proportion is exactly correct.
                - For structures with partial occupation, the chemical proportion numbers are integers that within reasonable approximation indicate the correct chemical proportions. The precise details of how to perform the rounding is chosen by the API implementation.
                - No spaces or separators are allowed.

            - **Examples**:
                - `"H2NaO"`
                - `"ClNa"`
                - `"CCaO3"`

            - **Query examples**:
                - A filter that matches an exactly given formula is `chemical_formula_reduced="H2NaO"`.
          nullable: true
          pattern: ^([A-Z][a-z]?\d*)*$
          title: Chemical Formula Reduced
          type: string
        dimension_types:
          description: |-
            List of three integers.
            For each of the three directions indicated by the three lattice vectors (see property `lattice_vectors`), this list indicates if the direction is periodic (value `1`) or non-periodic (value `0`).
            Note: the elements in this list each refer to the direction of the corresponding entry in `lattice_vectors` and *not* the Cartesian x, y, z directions.

            - **Type**: list of integers.

            - **Requirements/Conventions**:
                - **Support**: SHOULD be supported by all implementations, i.e., SHOULD NOT be `null`.
                - **Query**: Support for queries on this property is OPTIONAL.
                - MUST be a list of length 3.
                - Each integer element MUST assume only the value 0 or 1.

            - **Examples**:
                - For a molecule: `[0, 0, 0]`
                - For a wire along the direction specified by the third lattice vector: `[0, 0, 1]`
                - For a 2D surface/slab, periodic on the plane defined by the first and third lattice vectors: `[1, 0, 1]`
                - For a bulk 3D system: `[1, 1, 1]`
          items:
            $ref: "#/components/schemas/Periodicity"
          maxItems: 3
          minItems: 3
          nullable: true
          title: Dimension Types
          type: array
        elements:
          description: |-
            Symbols of the different elements present in the structure.

            - **Type**: list of strings.

            - **Requirements/Conventions**:
                - **Support**: SHOULD be supported by all implementations, i.e., SHOULD NOT be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.
                - The strings are the chemical symbols, i.e., either a single uppercase letter or an uppercase letter followed by a number of lowercase letters.
                - The order MUST be alphabetical.
                - MUST refer to the same elements in the same order, and therefore be of the same length, as `elements_ratios`, if the latter is provided.
                - Note: This property SHOULD NOT contain the string "X" to indicate non-chemical elements or "vacancy" to indicate vacancies (in contrast to the field `chemical_symbols` for the `species` property).

            - **Examples**:
                - `["Si"]`
                - `["Al","O","Si"]`

            - **Query examples**:
                - A filter that matches all records of structures that contain Si, Al **and** O, and possibly other elements: `elements HAS ALL "Si", "Al", "O"`.
                - To match structures with exactly these three elements, use `elements HAS ALL "Si", "Al", "O" AND elements LENGTH 3`.
                - Note: length queries on this property can be equivalently formulated by filtering on the `nelements`_ property directly.
          items:
            type: string
          nullable: true
          title: Elements
          type: array
        elements_ratios:
          description: |-
            Relative proportions of different elements in the structure.

            - **Type**: list of floats

            - **Requirements/Conventions**:
                - **Support**: SHOULD be supported by all implementations, i.e., SHOULD NOT be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.
                - Composed by the proportions of elements in the structure as a list of floating point numbers.
                - The sum of the numbers MUST be 1.0 (within floating point accuracy)
                - MUST refer to the same elements in the same order, and therefore be of the same length, as `elements`, if the latter is provided.

            - **Examples**:
                - `[1.0]`
                - `[0.3333333333333333, 0.2222222222222222, 0.4444444444444444]`

            - **Query examples**:
                - Note: Useful filters can be formulated using the set operator syntax for correlated values.
                  However, since the values are floating point values, the use of equality comparisons is generally inadvisable.
                - OPTIONAL: a filter that matches structures where approximately 1/3 of the atoms in the structure are the element Al is: `elements:elements_ratios HAS ALL "Al":>0.3333, "Al":<0.3334`.
          items:
            type: number
          nullable: true
          title: Elements Ratios
          type: array
        immutable_id:
          description: |-
            The entry's immutable ID (e.g., an UUID). This is important for databases having preferred IDs that point to "the latest version" of a record, but still offer access to older variants. This ID maps to the version-specific record, in case it changes in the future.

            - **Type**: string.

            - **Requirements/Conventions**:
                - **Support**: OPTIONAL support in implementations, i.e., MAY be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.

            - **Examples**:
                - `"8bd3e750-b477-41a0-9b11-3a799f21b44f"`
                - `"fjeiwoj,54;@=%<>#32"` (Strings that are not URL-safe are allowed.)
          title: Immutable Id
          type: string
        last_modified:
          description: |-
            Date and time representing when the entry was last modified.

            - **Type**: timestamp.

            - **Requirements/Conventions**:
                - **Support**: SHOULD be supported by all implementations, i.e., SHOULD NOT be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.
                - **Response**: REQUIRED in the response unless the query parameter `response_fields` is present and does not include this property.

            - **Example**:
                - As part of JSON response format: `"2007-04-05T14:30:20Z"` (i.e., encoded as an [RFC 3339 Internet Date/Time Format](https://tools.ietf.org/html/rfc3339#section-5.6) string.)
          format: date-time
          nullable: true
          title: Last Modified
          type: string
        lattice_vectors:
          description: |-
            The three lattice vectors in Cartesian coordinates, in ångström (Å).

            - **Type**: list of list of floats or unknown values.

            - **Requirements/Conventions**:
                - **Support**: SHOULD be supported by all implementations, i.e., SHOULD NOT be `null`.
                - **Query**: Support for queries on this property is OPTIONAL.
                  If supported, filters MAY support only a subset of comparison operators.
                - MUST be a list of three vectors *a*, *b*, and *c*, where each of the vectors MUST BE a list of the vector's coordinates along the x, y, and z Cartesian coordinates.
                  (Therefore, the first index runs over the three lattice vectors and the second index runs over the x, y, z Cartesian coordinates).
                - For databases that do not define an absolute Cartesian system (e.g., only defining the length and angles between vectors), the first lattice vector SHOULD be set along *x* and the second on the *xy*-plane.
                - MUST always contain three vectors of three coordinates each, independently of the elements of property `dimension_types`.
                  The vectors SHOULD by convention be chosen so the determinant of the `lattice_vectors` matrix is different from zero.
                  The vectors in the non-periodic directions have no significance beyond fulfilling these requirements.
                - The coordinates of the lattice vectors of non-periodic dimensions (i.e., those dimensions for which `dimension_types` is `0`) MAY be given as a list of all `null` values.
                    If a lattice vector contains the value `null`, all coordinates of that lattice vector MUST be `null`.

            - **Examples**:
                - `[[4.0,0.0,0.0],[0.0,4.0,0.0],[0.0,1.0,4.0]]` represents a cell, where the first vector is `(4, 0, 0)`, i.e., a vector aligned along the `x` axis of length 4 Å; the second vector is `(0, 4, 0)`; and the third vector is `(0, 1, 4)`.
          items:
            items:
              type: number
            maxItems: 3
            minItems: 3
            type: array
          maxItems: 3
          minItems: 3
          nullable: true
          title: Lattice Vectors
          type: array
        nelements:
          description: |-
            Number of different elements in the structure as an integer.

            - **Type**: integer

            - **Requirements/Conventions**:
                - **Support**: SHOULD be supported by all implementations, i.e., SHOULD NOT be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.
                - MUST be equal to the lengths of the list properties `elements` and `elements_ratios`, if they are provided.

            - **Examples**:
                - `3`

            - **Querying**:
                - Note: queries on this property can equivalently be formulated using `elements LENGTH`.
                - A filter that matches structures that have exactly 4 elements: `nelements=4`.
                - A filter that matches structures that have between 2 and 7 elements: `nelements>=2 AND nelements<=7`.
          nullable: true
          title: Nelements
          type: integer
        nperiodic_dimensions:
          description: |-
            An integer specifying the number of periodic dimensions in the structure, equivalent to the number of non-zero entries in `dimension_types`.

            - **Type**: integer

            - **Requirements/Conventions**:
                - **Support**: SHOULD be supported by all implementations, i.e., SHOULD NOT be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.
                - The integer value MUST be between 0 and 3 inclusive and MUST be equal to the sum of the items in the `dimension_types` property.
                - This property only reflects the treatment of the lattice vectors provided for the structure, and not any physical interpretation of the dimensionality of its contents.

            - **Examples**:
                - `2` should be indicated in cases where `dimension_types` is any of `[1, 1, 0]`, `[1, 0, 1]`, `[0, 1, 1]`.

            - **Query examples**:
                - Match only structures with exactly 3 periodic dimensions: `nperiodic_dimensions=3`
                - Match all structures with 2 or fewer periodic dimensions: `nperiodic_dimensions<=2`
          nullable: true
          title: Nperiodic Dimensions
          type: integer
        nsites:
          description: |-
            An integer specifying the length of the `cartesian_site_positions` property.

            - **Type**: integer

            - **Requirements/Conventions**:
                - **Support**: SHOULD be supported by all implementations, i.e., SHOULD NOT be `null`.
                - **Query**: MUST be a queryable property with support for all mandatory filter features.

            - **Examples**:
                - `42`

            - **Query examples**:
                - Match only structures with exactly 4 sites: `nsites=4`
                - Match structures that have between 2 and 7 sites: `nsites>=2 AND nsites<=7`
          nullable: true
          title: Nsites
          type: integer
        species:
          description: |-
            A list describing the species of the sites of this structure.
            Species can represent pure chemical elements, virtual-crystal atoms representing a statistical occupation of a given site by multiple chemical elements, and/or a location to which there are attached atoms, i.e., atoms whose precise location are unknown beyond that they are attached to that position (frequently used to indicate hydrogen atoms attached to another element, e.g., a carbon with three attached hydrogens might represent a methyl group, -CH3).

            - **Type**: list of dictionary with keys:
                - `name`: string (REQUIRED)
                - `chemical_symbols`: list of strings (REQUIRED)
                - `concentration`: list of float (REQUIRED)
                - `attached`: list of strings (REQUIRED)
                - `nattached`: list of integers (OPTIONAL)
                - `mass`: list of floats (OPTIONAL)
                - `original_name`: string (OPTIONAL).

            - **Requirements/Conventions**:
                - **Support**: SHOULD be supported by all implementations, i.e., SHOULD NOT be `null`.
                - **Query**: Support for queries on this property is OPTIONAL.
                    If supported, filters MAY support only a subset of comparison operators.
                - Each list member MUST be a dictionary with the following keys:
                    - **name**: REQUIRED; gives the name of the species; the **name** value MUST be unique in the `species` list;
                    - **chemical_symbols**: REQUIRED; MUST be a list of strings of all chemical elements composing this species.
                      Each item of the list MUST be one of the following:
                        - a valid chemical-element symbol, or
                        - the special value `"X"` to represent a non-chemical element, or
                        - the special value `"vacancy"` to represent that this site has a non-zero probability of having a vacancy (the respective probability is indicated in the `concentration` list, see below).

                      If any one entry in the `species` list has a `chemical_symbols` list that is longer than 1 element, the correct flag MUST be set in the list `structure_features`.

                    - **concentration**: REQUIRED; MUST be a list of floats, with same length as `chemical_symbols`.
                      The numbers represent the relative concentration of the corresponding chemical symbol in this species.
                      The numbers SHOULD sum to one. Cases in which the numbers do not sum to one typically fall only in the following two categories:

                        - Numerical errors when representing float numbers in fixed precision, e.g. for two chemical symbols with concentrations `1/3` and `2/3`, the concentration might look something like `[0.33333333333, 0.66666666666]`. If the client is aware that the sum is not one because of numerical precision, it can renormalize the values so that the sum is exactly one.
                        - Experimental errors in the data present in the database. In this case, it is the responsibility of the client to decide how to process the data.

                        Note that concentrations are uncorrelated between different sites (even of the same species).

                    - **attached**: OPTIONAL; if provided MUST be a list of length 1 or more of strings of chemical symbols for the elements attached to this site, or "X" for a non-chemical element.

                    - **nattached**: OPTIONAL; if provided MUST be a list of length 1 or more of integers indicating the number of attached atoms of the kind specified in the value of the `attached` key.

                      The implementation MUST include either both or none of the `attached` and `nattached` keys, and if they are provided, they MUST be of the same length.
                      Furthermore, if they are provided, the `structure_features` property MUST include the string `site_attachments`.

                    - **mass**: OPTIONAL. If present MUST be a list of floats, with the same length as `chemical_symbols`, providing element masses expressed in a.m.u.
                      Elements denoting vacancies MUST have masses equal to 0.

                    - **original_name**: OPTIONAL. Can be any valid Unicode string, and SHOULD contain (if specified) the name of the species that is used internally in the source database.

                      Note: With regards to "source database", we refer to the immediate source being queried via the OPTIMADE API implementation.

                      The main use of this field is for source databases that use species names, containing characters that are not allowed (see description of the list property `species_at_sites`).

                - For systems that have only species formed by a single chemical symbol, and that have at most one species per chemical symbol, SHOULD use the chemical symbol as species name (e.g., `"Ti"` for titanium, `"O"` for oxygen, etc.)
                  However, note that this is OPTIONAL, and client implementations MUST NOT assume that the key corresponds to a chemical symbol, nor assume that if the species name is a valid chemical symbol, that it represents a species with that chemical symbol.
                  This means that a species `{"name": "C", "chemical_symbols": ["Ti"], "concentration": [1.0]}` is valid and represents a titanium species (and *not* a carbon species).
                - It is NOT RECOMMENDED that a structure includes species that do not have at least one corresponding site.

            - **Examples**:
                - `[ {"name": "Ti", "chemical_symbols": ["Ti"], "concentration": [1.0]} ]`: any site with this species is occupied by a Ti atom.
                - `[ {"name": "Ti", "chemical_symbols": ["Ti", "vacancy"], "concentration": [0.9, 0.1]} ]`: any site with this species is occupied by a Ti atom with 90 % probability, and has a vacancy with 10 % probability.
                - `[ {"name": "BaCa", "chemical_symbols": ["vacancy", "Ba", "Ca"], "concentration": [0.05, 0.45, 0.5], "mass": [0.0, 137.327, 40.078]} ]`: any site with this species is occupied by a Ba atom with 45 % probability, a Ca atom with 50 % probability, and by a vacancy with 5 % probability. The mass of this site is (on average) 88.5 a.m.u.
                - `[ {"name": "C12", "chemical_symbols": ["C"], "concentration": [1.0], "mass": [12.0]} ]`: any site with this species is occupied by a carbon isotope with mass 12.
                - `[ {"name": "C13", "chemical_symbols": ["C"], "concentration": [1.0], "mass": [13.0]} ]`: any site with this species is occupied by a carbon isotope with mass 13.
                - `[ {"name": "CH3", "chemical_symbols": ["C"], "concentration": [1.0], "attached": ["H"], "nattached": [3]} ]`: any site with this species is occupied by a methyl group, -CH3, which is represented without specifying precise positions of the hydrogen atoms.
          items:
            $ref: "#/components/schemas/Species"
          nullable: true
          title: Species
          type: array
        species_at_sites:
          description: |-
            Name of the species at each site (where values for sites are specified with the same order of the property `cartesian_site_positions`).
            The properties of the species are found in the property `species`.

            - **Type**: list of strings.

            - **Requirements/Conventions**:
                - **Support**: SHOULD be supported by all implementations, i.e., SHOULD NOT be `null`.
                - **Query**: Support for queries on this property is OPTIONAL.
                  If supported, filters MAY support only a subset of comparison operators.
                - MUST have length equal to the number of sites in the structure (first dimension of the list property `cartesian_site_positions`).
                - Each species name mentioned in the `species_at_sites` list MUST be described in the list property `species` (i.e. for each value in the `species_at_sites` list there MUST exist exactly one dictionary in the `species` list with the `name` attribute equal to the corresponding `species_at_sites` value).
                - Each site MUST be associated only to a single species.
                  **Note**: However, species can represent mixtures of atoms, and multiple species MAY be defined for the same chemical element.
                  This latter case is useful when different atoms of the same type need to be grouped or distinguished, for instance in simulation codes to assign different initial spin states.

            - **Examples**:
                - `["Ti","O2"]` indicates that the first site is hosting a species labeled `"Ti"` and the second a species labeled `"O2"`.
                - `["Ac", "Ac", "Ag", "Ir"]` indicating the first two sites contains the `"Ac"` species, while the third and fourth sites contain the `"Ag"` and `"Ir"` species, respectively.
          items:
            type: string
          nullable: true
          title: Species At Sites
          type: array
        structure_features:
          description: |-
            A list of strings that flag which special features are used by the structure.

            - **Type**: list of strings

            - **Requirements/Conventions**:
                - **Support**: MUST be supported by all implementations, MUST NOT be `null`.
                - **Query**: MUST be a queryable property.
                Filters on the list MUST support all mandatory HAS-type queries.
                Filter operators for comparisons on the string components MUST support equality, support for other comparison operators are OPTIONAL.
                - MUST be an empty list if no special features are used.
                - MUST be sorted alphabetically.
                - If a special feature listed below is used, the list MUST contain the corresponding string.
                - If a special feature listed below is not used, the list MUST NOT contain the corresponding string.
                - **List of strings used to indicate special structure features**:
                    - `disorder`: this flag MUST be present if any one entry in the `species` list has a `chemical_symbols` list that is longer than 1 element.
                    - `implicit_atoms`: this flag MUST be present if the structure contains atoms that are not assigned to sites via the property `species_at_sites` (e.g., because their positions are unknown).
                       When this flag is present, the properties related to the chemical formula will likely not match the type and count of atoms represented by the `species_at_sites`, `species` and `assemblies` properties.
                    - `site_attachments`: this flag MUST be present if any one entry in the `species` list includes `attached` and `nattached`.
                    - `assemblies`: this flag MUST be present if the property `assemblies` is present.

            - **Examples**: A structure having implicit atoms and using assemblies: `["assemblies", "implicit_atoms"]`
          items:
            $ref: "#/components/schemas/StructureFeatures"
          title: Structure Features
          type: array
      required:
        - last_modified
        - elements
        - nelements
        - elements_ratios
        - chemical_formula_descriptive
        - chemical_formula_reduced
        - chemical_formula_anonymous
        - dimension_types
        - nperiodic_dimensions
        - lattice_vectors
        - cartesian_site_positions
        - nsites
        - species
        - species_at_sites
        - structure_features
      title: StructureResourceAttributes
      type: object
    StructureResponseMany:
      description: errors are not allowed
      properties:
        data:
          anyOf:
            - items:
                $ref: "#/components/schemas/StructureResource"
              type: array
            - items:
                type: object
              type: array
          description: List of unique OPTIMADE structures entry resource objects
          title: Data
          uniqueItems: true
        errors:
          description: A list of unique errors
          items:
            $ref: "#/components/schemas/Error"
          title: Errors
          type: array
          uniqueItems: true
        included:
          anyOf:
            - items:
                $ref: "#/components/schemas/EntryResource"
              type: array
            - items:
                type: object
              type: array
          title: Included
          uniqueItems: true
        jsonapi:
          allOf:
            - $ref: "#/components/schemas/JsonApi"
          description: Information about the JSON API used
          title: Jsonapi
        links:
          allOf:
            - $ref: "#/components/schemas/ToplevelLinks"
          description: Links associated with the primary data or errors
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/ResponseMeta"
          description: A meta object containing non-standard information
          title: Meta
      required:
        - data
        - meta
      title: StructureResponseMany
      type: object
    StructureResponseOne:
      description: errors are not allowed
      properties:
        data:
          anyOf:
            - $ref: "#/components/schemas/StructureResource"
            - type: object
          description: A single structures entry resource
          title: Data
        errors:
          description: A list of unique errors
          items:
            $ref: "#/components/schemas/Error"
          title: Errors
          type: array
          uniqueItems: true
        included:
          anyOf:
            - items:
                $ref: "#/components/schemas/EntryResource"
              type: array
            - items:
                type: object
              type: array
          title: Included
          uniqueItems: true
        jsonapi:
          allOf:
            - $ref: "#/components/schemas/JsonApi"
          description: Information about the JSON API used
          title: Jsonapi
        links:
          allOf:
            - $ref: "#/components/schemas/ToplevelLinks"
          description: Links associated with the primary data or errors
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/ResponseMeta"
          description: A meta object containing non-standard information
          title: Meta
      required:
        - data
        - meta
      title: StructureResponseOne
      type: object
    ToplevelLinks:
      description: A set of Links objects, possibly including pagination
      properties:
        first:
          anyOf:
            - format: uri
              maxLength: 65536
              minLength: 1
              type: string
            - $ref: "#/components/schemas/Link"
          description: The first page of data
          title: First
        last:
          anyOf:
            - format: uri
              maxLength: 65536
              minLength: 1
              type: string
            - $ref: "#/components/schemas/Link"
          description: The last page of data
          title: Last
        next:
          anyOf:
            - format: uri
              maxLength: 65536
              minLength: 1
              type: string
            - $ref: "#/components/schemas/Link"
          description: The next page of data
          title: Next
        prev:
          anyOf:
            - format: uri
              maxLength: 65536
              minLength: 1
              type: string
            - $ref: "#/components/schemas/Link"
          description: The previous page of data
          title: Prev
        related:
          anyOf:
            - format: uri
              maxLength: 65536
              minLength: 1
              type: string
            - $ref: "#/components/schemas/Link"
          description: A related resource link
          title: Related
        self:
          anyOf:
            - format: uri
              maxLength: 65536
              minLength: 1
              type: string
            - $ref: "#/components/schemas/Link"
          description: A link to itself
          title: Self
      title: ToplevelLinks
      type: object
    Warnings:
      description: |-
        OPTIMADE-specific warning class based on OPTIMADE-specific JSON API Error.

        From the specification:

        A warning resource object is defined similarly to a JSON API error object, but MUST also include the field type, which MUST have the value "warning".
        The field detail MUST be present and SHOULD contain a non-critical message, e.g., reporting unrecognized search attributes or deprecated features.

        Note: Must be named "Warnings", since "Warning" is a built-in Python class.
      properties:
        code:
          description: an application-specific error code, expressed as a string value.
          title: Code
          type: string
        detail:
          description: A human-readable explanation specific to this occurrence of the problem.
          title: Detail
          type: string
        id:
          description: A unique identifier for this particular occurrence of the problem.
          title: Id
          type: string
        links:
          allOf:
            - $ref: "#/components/schemas/ErrorLinks"
          description: A links object storing about
          title: Links
        meta:
          allOf:
            - $ref: "#/components/schemas/Meta"
          description: a meta object containing non-standard meta-information about the error.
          title: Meta
        source:
          allOf:
            - $ref: "#/components/schemas/ErrorSource"
          description: An object containing references to the source of the error
          title: Source
        title:
          description: A short, human-readable summary of the problem. It **SHOULD NOT** change from occurrence to occurrence of the problem, except for purposes of localization.
          title: Title
          type: string
        type:
          description: Warnings must be of type "warning"
          pattern: ^warning$
          title: Type
          type: string
      required:
        - detail
        - type
      title: Warnings
      type: object
