<xsd:simpleType name="moleculeIDType" id="st.moleculeIDType">
    <xsd:annotation>
        <xsd:documentation>
            <h:div class="summary" xmlns:h="http://www.w3.org/1999/xhtml">An identifier for an molecule.</h:div>
            <h:div class="description" xmlns:h="http://www.w3.org/1999/xhtml">
                <h:p>Of the form prefix:suffix where prefix and suffix
         are purely alphanumeric (with _ and -) and prefix
         is optional. This is similar to XML IDs (and we promote
         this as good practice for moleculeIDs. Other punctuation and 
         whitespace is forbidden, so IDs from (say) PDB files are
         not satisfactory.</h:p>
                <h:p>The prefix is intended to form a pseudo-namespace so that
         molecule IDs in different molecules may have identical suffixes. 
         It is also useful if the prefix is the ID for the molecule
         (though this clearly has its limitation). molecule IDs should not
         be typed as XML IDs since they may not validate.</h:p>
            </h:div>
            <h:div class="curation" xmlns:h="http://www.w3.org/1999/xhtml">2006-11-24: PMR created.</h:div>
            <h:div class="example" href="moleculeIDType1.xml" xmlns:h="http://www.w3.org/1999/xhtml" />
        </xsd:documentation>
        <xsd:appinfo />
    </xsd:annotation>
    <xsd:restriction base="xsd:string">
        <xsd:pattern value="[A-Za-z_][A-Za-z0-9_\-]*(:[A-Za-z0-9_\-]+)?" />
    </xsd:restriction>
</xsd:simpleType>