A univalent radical or functional group, (-OH), in organic chemistry; present in alcohols, phenols, carboxylic acids and certain other classes of compounds
A heterocyclic organic compound containing two nitrogen atoms separated by a carbon atom in a five-membered ring, called 1,3-diazole in w:IUPAC nomenclature.
A univalent hydrocarbon radical (C6H5) formally derived from benzene by the removal of a hydrogen atom, and the basis of an immense number of aromatic derivatives.