Heptazine

Heptazine, or 'tri-s-triazine or cyamelurine', is a chemical compound with formula , that consists of a planar triangular core group or three fused triazine rings, with three hydrogen atoms at the corners. It is a yellow, weakly fluorescent solid with melting point over . It is soluble in organic solvents such as acetonitrile, but is decomposed by water and light.

The name "heptazine" is also used for derivative compounds, which have the three hydrogens substituted by other functional groups. Heptazine oligomers and polymers were discovered in the 19th century, but their study has long been hampered by their poor solubility. They are used as flame retardants. Heptazine derivatives have been the object of interest recently for potential applications in organic electronics, explosives, and more. The synthesis of heptazine proper was reported only in 1982.