CML element unit

Abstract	false (This can be used in an instance)
Nillable	false (Instance values cannot use xsi:nil)
Target Namespace	http://www.xml-cml.org/schema/stmml
Declared Namespaces	xmlns:sch=http://www.ascc.net/xml/schematron xmlns:xsd=http://www.w3.org/2001/XMLSchema xmlns=http://www.xml-cml.org/schema/stmml

<xsd:element name="unit" id="el.unit">
    <xsd:annotation>
        <xsd:documentation>
            <div class="summary">A scientific unit</div>
            <div class="description">
                <p>A scientific unit. Units are of the following types:</p>
                <ul>
                    <li>
SI Units. These may be one of the seven fundamental types
(e.g. meter) or may be derived (e.g. joule). An SI unit is
identifiable because it has no parentSI attribute and will have
a unitType attribute.
                    </li>
                    <li>
nonSI Units. These will normally have a parent SI unit
(e.g. calorie has joule as an SI parent).
                    </li>
                    <li/>
                </ul>
                <p>Example:</p>
                <pre>
<unit id="units:fahr" name="fahrenheit" parentSI="units:K"
multiplierToSI="0.55555555555555555"
constantToSI="-17.777777777777777777">
<description>An obsolescent unit of temperature still used in popular
meteorology</description>
</unit>
                </pre>
            </div>
        </xsd:documentation>
        <xsd:appinfo>

        </xsd:appinfo>
    </xsd:annotation>
    <xsd:complexType>
        <xsd:choice minOccurs="0" maxOccurs="unbounded">
            <xsd:element ref="description"/>
            <xsd:element ref="annotation"/>
        </xsd:choice>
        <xsd:attribute name="id" type="xsd:string" use="required"/>
        <xsd:attribute name="abbreviation" type="xsd:string"/>
        <xsd:attribute name="name" type="xsd:string"/>
        <xsd:attribute name="parentSI" type="xsd:string">
            <xsd:annotation>
                <xsd:documentation>
                    <div class="summary">A reference to the parent SI unit (forbidden for SI Units themselves).</div>
                </xsd:documentation>
            </xsd:annotation>
        </xsd:attribute>
        <xsd:attribute name="unitType" type="xsd:string">
            <xsd:annotation>
                <xsd:documentation>
                    <div class="summary">A reference to the unitType (required for SI Units).</div>
                </xsd:documentation>
            </xsd:annotation>
        </xsd:attribute>
        <xsd:attribute name="multiplierToSI" type="xsd:decimal">
            <xsd:annotation>
                <xsd:documentation>
                    <div class="summary">
                        <p>
The factor by which the non-SI unit should be multiplied to
convert a quantity to its representation in SI Units.
This is applied
                            <b>before</b>
                            <tt>constantToSI</tt>
.
necessarily unity for SI units
                        </p>
                    </div>
                </xsd:documentation>
            </xsd:annotation>
        </xsd:attribute>
        <xsd:attribute name="constantToSI" type="xsd:decimal">
            <xsd:annotation>
                <xsd:documentation>
                    <div class="summary">
                        <p>
The amount to add to a quantity in non-SI units to
convert its representation to SI Units.
This is applied
                            <b>after</b>
                            <tt>multiplierToSI</tt>
.
necessarily zero for SI units.
                        </p>
                    </div>
                </xsd:documentation>
            </xsd:annotation>
        </xsd:attribute>
    </xsd:complexType>
</xsd:element>

A scientific unit. Units are of the following types:

SI Units. These may be one of the seven fundamental types (e.g. meter) or may be derived (e.g. joule). An SI unit is identifiable because it has no parentSI attribute and will have a unitType attribute.
nonSI Units. These will normally have a parent SI unit (e.g. calorie has joule as an SI parent).

Example:

<unit id="units:fahr" name="fahrenheit" parentSI="units:K"
  multiplierToSI="0.55555555555555555"
  constantToSI="-17.777777777777777777">
    <description>An obsolescent unit of temperature still used in popular
      meteorology</description>
</unit>

element {http://www.xml-cml.org/schema/stmml}unit

Source

Documentation