2-Carboxy­pyridinium hydrogen chloranilate

The title compound, C₆H₆NO₂⁺·C₆HCl₂O₄⁻, is the salt of chloranilic acid with nicotinic acid (2-carboxy­piridine), where an acid–base inter­action involving a proton transfer is observed from the chloranilic acid to the pyridine group of nicotinic acid. In the crystal structure, the hydrogen chloranilate anion and the 2-carboxy­pridinium cation are linked by N—H...O and O—H...O hydrogen bonds to form a zigzag chain. The chains are further linked by O—H...O hydrogen bonds to form a three-dimensional hydrogen-bond network.