Crystal structure of ethyl-ene-dioxy-tetra-thia-fulvalene-4,5-bis-(thiol-benzoic acid) 0.25-hydrate.

In the title compound (systematic name: 4,4'-{[2-(5,6-di-hydro-[1,3]di-thiolo[4,5-][1,4]dioxin-2-yl-idene)-1,3-di-thiole-4,5-di-yl]bis-(sulfanedi-yl)}di-benzoic acid 0.25-hydrate), CHOS·0.25HO, the tetra-thia-fulvalene (TTF) core adopts a boat conformation, where the central SC=CS plane makes dihedral angles of 31.34 (4) and 26.83 (6)°, respectively, with the peripheral SC=CS and SCO planes. In the crystal, the benzoic acid mol-ecules are linked O-H⋯O hydrogen bonds, forming inversion dimers with (8) motifs. The dimers are linked through weak C-H⋯O hydrogen bonds into a chain structure along [-101]. The chains stack along the axis through S⋯S and S⋯C short contacts, forming layers parallel to the plane.