Hermann-Mauguin entry (property)

{
    "$id": "https://schemas.anyterial.se/defs/v0.1/properties/spacegroups/hm_entry",
    "$schema": "https://schemas.optimade.org/meta/v1.3/optimade/property_definition.json",
    "title": "Hermann-Mauguin entry",
    "x-optimade-type": "string",
    "x-optimade-definition": {
        "kind": "property",
        "version": "0.1.0",
        "format": "1.3",
        "name": "hm_entry",
        "label": "hm_entry_spacegroups"
    },
    "type": [
        "string",
        "null"
    ],
    "description": "The Hermann-Mauguin entry label for a conventional space-group setting from table A1.4.2.7 of the [International Tables for Crystallography (2006). Volume B, Reciprocal space. ISBN: 978-0-7923-6592-1, doi:10.1107/97809553602060000102](https://doi.org/10.1107/97809553602060000102).\n\nThe symbol is a full Hermann-Mauguin-style setting label, except that:\n\n* The older glide-plane letters are used, rather than the newer `e` notation introduced in the Fourth Edition of the International Tables for Crystallography (1995) for the space groups Aem2 (39), Aea2 (41), Cmce (64), Cmme (67) and Ccce (68).\n* When necessary to disambiguate the 530 conventional settings, an origin-choice suffix (`:1`, `:2`) is used.\n\n**Requirements/Conventions**:\n\n- The value MUST be written as a plain string with spaces between Hermann-Mauguin symbol parts.\n- The disambiguation suffix MUST be a colon `:`  and an integer appended to the string without whitespace, for example `:1` or `:2`.",
    "x-optimade-unit": "inapplicable",
    "examples": [
        "P 1",
        "C c c a:1",
        "C c c b:2"
    ]
}