4-(Dimethylamino)pyridmium 2-butoxy-3-dicyanomethylene-4-oxocyclobut-1-en- 1-olate

In the crystal structure of the title compound, C₇H ₁₁N₂⁺·C₁₁H₉N ₂O₃^-, both the cation and the anion lie on a mirror plane. Three C atoms of the butyl group are disordered over two positions related by this plane. The bond-length analysis shows that the surplus negative charge of the anion is delocalized between the cyclobutene ring and the dicyanomethylene group. The 4-dimethylaminopyridinium cation has an intermediate aromatic-quinoid structure.