Sulfonated 1,3-bis­(4-pyrid­yl)propane

In the title compound, 4-[3-(3-sulfonato­pyridin-1-ium-4-yl)prop­yl]pyridin-1-ium-3-sulfonate, C13H14N2O6S2, the mol­ecule is zwitterionic, with the sulfonic acid proton transfered to the basic pyridine N atom. Also, the structure adopts a butterfly-like conformation with the sulfonate groups on opposite sides of the ‘wings’. The dihedral angle between the two pyridinium rings is 83.56 (7)°, and this results in the mol­ecule having a chiral conformation and packing. There is strong inter­molecular hydrogen bonding between the pyridinium H and sulfonate O atoms of adjoining mol­ecules. In addition, there are weaker inter­molecular C—H⋯O inter­actions