Wyckoff positions (property)

{
    "$id": "https://schemas.optimade.org/defs/v1.3/properties/optimade/structures/wyckoff_positions",
    "$schema": "https://schemas.optimade.org/meta/v1.2/optimade/property_definition.json",
    "title": "Wyckoff positions",
    "x-optimade-type": "list",
    "x-optimade-definition": {
        "label": "wyckoff_positions_optimade_structures",
        "kind": "property",
        "version": "1.3.0",
        "format": "1.2",
        "name": "wyckoff_positions"
    },
    "x-optimade-dimensions": {
        "names": [
            "dim_sites"
        ],
        "sizes": [
            null
        ]
    },
    "type": [
        "array",
        "null"
    ],
    "description": "A list of Wyckoff symbols of sites (where values for sites are specified with the same order of the property `cartesian_site_positions` and/or `fractional_site_positions`).\n\n**Requirements/Conventions**:\n\n- MUST have length equal to the number of sites in the structure (first dimension of the list properties `cartesian_site_positions` and/or `fractional_site_positions`).\n- If provided, MUST list a single letter (`a`-`z` or `\u03b1`) Wyckoff position for each site in the structure according to the International Tables for Crystallography vol. A (IUCr, 2016).\n\n**Bibliographic References**:\n\n- IUCr (2016). International Tables for Crystallography vol. A. Space-group Symmetry, Ed. M. I. Aroyo, 6-th edition. Chichester, John Wiley & Sons.",
    "x-optimade-unit": "inapplicable",
    "items": {
        "$id": "https://schemas.optimade.org/defs/v1.3/properties/optimade/common/wyckoff_position",
        "title": "Wyckoff position",
        "x-optimade-type": "string",
        "x-optimade-definition": {
            "label": "wyckoff_position_optimade_common",
            "kind": "property",
            "version": "1.3.0",
            "format": "1.2",
            "name": "wyckoff_position"
        },
        "description": "The Wyckoff symbol for a site.",
        "x-optimade-unit": "inapplicable",
        "type": [
            "string"
        ],
        "maxLength": 1,
        "enum": [
            "a",
            "b",
            "c",
            "d",
            "e",
            "f",
            "g",
            "h",
            "i",
            "j",
            "k",
            "l",
            "m",
            "n",
            "o",
            "p",
            "q",
            "r",
            "s",
            "t",
            "u",
            "v",
            "w",
            "x",
            "y",
            "z",
            "\u03b1"
        ]
    }
}