Three-dimensional hydrogen-bonded assembly in 2,2'-disulfanylidene-5,5'-biimidazolidinylidene-4,4'-dione-dimethylformamide-water (3/2/4).

The title compound, 3C6H4N4O2S2·2C3H7NO·4H2O, comprises three 2,2'-disulfanylidene-5,5'-biimidazolidinylidene-4,4'-dione molecules, two dimethylformamide molecules and four water molecules arranged around a crystallographic inversion centre. The non-H atoms within the 5,5'-biimidazolidinylidene molecule are coplanar and these molecules aggregate through N-H···S hydrogen-bonding interactions with cyclic motifs [graph set R2(2)(8)], giving two-dimensional ribbon structures which are close to being parallel. The two independent water molecules associate to form centrosymmetric cyclic hydrogen-bonded (H2O)4 tetrameric units [graph set R4(4)(8)]. The ribbon structures extend along the a axis and are linked through the water tetramers and the dimethylformamide molecules by a combination of two- and three-centre hydrogen bonds, giving an overall three-dimensional structure.