Optional_Optional_Specified per moiety according to the Hill system
OptionalextensionAdditional content defined by implementations
OptionalidUnique id for inter-element referencing
OptionalmodifierExtensions that cannot be ignored even if unrecognized
OptionalmolecularMolecular formula (e.g. using the Hill system)
OptionalmolecularSpecified per moiety according to the Hill system
OptionalmolecularThe molecular weight or weight range
OptionalopticalOptical activity type
OptionalrepresentationA depiction of the structure or characterization of the substance
OptionalsourceSource of information for the structure
OptionalstereochemistryStereochemistry type
OptionaltechniqueThe method used to find the structure e.g. X-ray, NMR
Molecular formula (e.g. using the Hill system)