Crystal structure of 4,4'-(ethene-1,2-di-yl)dipyridinium bis-(3-carb-oxy-benzene-sulfonate).

In the title mol-ecular salt, C12H12N2 (2+)·2C7H5O5S(-), the complete dication is generated by crystallographic inversion symmetry. In the anion, the sulfonic acid group is deprotonated and the dihedral angle between the planes of the carb-oxy-lic acid group and the benzene ring is 12.41 (11)°. In the crystal, the anions are linked into inversion dimers by pairs of O-H⋯O hydrogen bonds, which generate R 2 (2)(16) loops. The dications link the anion dimers into [10-2] chains via N-H⋯O hydrogen bonds.