• One of two isomeric aromatic compounds with composition C<sub>2</sub>H<sub>3</sub>N<sub>3</sub>, having a five-membered ring of two carbon atoms and three nitrogen atoms.
  • A compound derived from one of these isomers.
  • <em>A</em> class-name applied, in organic chemistry, to compounds containing in their molecule a cyclic group consisting of three nitrogen and two carbon atoms, such as Various arrangements of these atoms are possible.
  • either of two <xref>isomeric</xref> <xref>heterocyclic</xref> compounds having a five-membered ring with three <xref>nitrogen</xref> atoms and two <xref>double bonds</xref> in the ring; any <xref>organic</xref> <xref>derivative</xref> of these compounds
powered by