tonne, t (unit)

{
    "$id": "https://schemas.optimade.org/defs/v1.2/units/si/1970/accepted/tonne",
    "$schema": "https://schemas.optimade.org/meta/v1.2/optimade/physical_unit_definition.json",
    "title": "tonne",
    "symbol": "t",
    "display-symbol": "t",
    "alternate-symbols": [
        "t"
    ],
    "description": "A unit of mass defined as 1000 kg, with kilogram defined according to the 1960 SI units.\n\nThe International System of Units (SI), 1st ed. (1970) defines the tonne as \"1 t = 10\u00b3 kg\" with the footnote \"The symbol and the unit was defined in resolution 7 at the 9th meeting of the C.G.P.M. (1948).\"\n\n- The International System of Units (SI), 1st ed. (1970) categorizes the unit as \"Units used with the International System\"\n- The International System of Units (SI), 3rd ed. (19) changes the reference of the definition to the 1879 meeting of the CIPM page 41.\n- The International System of Units (SI), 6th ed. (1991) further adds \"In some English-speaking countries this unit is called \u226ametric ton\u226b.\"",
    "resources": [
        {
            "relation": "Definition in the International System of Units (SI), 1st Edition",
            "resource-id": "https://www.bipm.org/en/publications/si-brochure"
        },
        {
            "relation": "Wikipedia article describing the unit",
            "resource-id": "https://en.wikipedia.org/wiki/Tonne"
        }
    ],
    "defining-relation": {
        "base-units": [
            {
                "symbol": "kg",
                "id": "https://schemas.optimade.org/defs/v1.2/units/si/1960/base/kilogram"
            }
        ],
        "base-units-expression": "kg",
        "scale": {
            "exponent": 3
        }
    },
    "x-optimade-definition": {
        "label": "tonne_si_1970_accepted",
        "kind": "unit",
        "format": "1.2",
        "version": "1.2.0",
        "name": "tonne"
    }
}