Synthesis and crystal structure of 2-(1,3-dithietan-2-yl-idene)cyclo-hexane-1,3-dione.

The title compound, CHOS, contains a cyclo-hexane-1,3-dione ring, which has a twist-boat conformation. The CS ring is close to planar (r.m.s. deviation = 0.023 Å) and the dihedral angle between the mean planes of the cyclo-hexane and 1,3-dithietane rings is 9.1 (3)°. Short intra-molecular S⋯O contacts occur [2.719 (5) and 2.740 (5) Å]. In the crystal, the mol-ecules are linked by weak C-H⋯S hydrogen bonds and short [3.165 (5) Å] S⋯O contacts, forming (010) layers. The prevalence of these inter-actions is illustrated by an analysis of the three-dimensional Hirshfeld surface and by two-dimensional fingerprint plots.