1:1 Co-crystal of 4,4'-(ethene-1,2-di-yl)dipyridin-1-ium sulfate and hexa-aqua-iron(II) sulfate monohydrate.

In the title hydrated double salt, 4,4'-(ethene-1,2-di-yl)dipyridin-1-ium hexa-aqua-iron(II) bis-(sulfate) monohydrate, (C12H12N2)[Fe(H2O)6](SO4)2·H2O, the Fe(II) cation is coordin-ated by six water mol-ecules in a slightly distorted octa-hedral geometry; the two pyridine rings of the 4,4'-(ethene-1,2-di-yl)dipyridin-1-ium cation are twisted to each other by a dihedral angle of 11.84 (10)°. In the crystal, the cations, sulfate anions and water mol-ecules of crystallization are linked by O-H⋯O, N-H⋯O and weak C-H⋯O hydrogen bonds, forming a three-dimensional supra-molecular network.