A rare positively charged nicotinic acid di-sulfide: 2,2'-di-thio-dinicotinic acid hydro-chloride monohydrate.

The title compound {systematic name: 3-carb-oxy-2-[2-(3-carb-oxy-pyridin-2-yl)disulfan-1-yl)]pyridin-1-ium chloride monohydrate}, CHNOS·Cl·HO, crystallizes in the triclinic space group . A pair of 2-mercaptonicotinic acid moieties is connected by a 2,2'-di-sulfide bond with a dihedral angle of 78.79 (3)°.