A triclinic polymorph of 4-cyano-pyridinium hydrogen chloranilate

The asymmetric unit of the triclinic polymorph of the title compound (systematic name: 4-cyanopyridinium 2,5-dichloro-4-hydroxy-3,6-dioxocyclohexa-1, 4-dien-1-olate), C6H₅N₂⁺·-C ₆HCl₂O₄^-, consists of two crystallographically independent cation-anion units, in each of which the cation and the anion are linked by an N - H O hydrogen bond. In the units, the dihedral angles between the cation and anion rings are 78.43 (11) and 80.71 (11)°. In the crystal, each unit independently forms a chain through N - H···O and O - H···N hydrogen bonds; one chain runs along the c axis while the other runs along [011]. Weak C - H···O, C - H···N and C - H···Cl interactions are observed between the chains.