Crystal structures of 4,4'-(disulfane-1,2-diyl)bis(5-methyl-2H-1,3-dithiol-2-one) and 4,4'-(diselanane-1,2-diyl)bis(5-methyl-2H-1,3-dithiol-2-one).

The two title compounds, C8H6O2S6 and C8H6O2S4Se2, are isotypic with very similar cell parameters. The complete mol-ecules constitute the asymmetric units, despite being chemically perfectly symmetric. The most prominant differences in the metrical parameters arise from the distinct sizes of sulfur and selenium in the dichalcogenide bridges, with C-S-S-C and C-Se-Se-C torsion angles of 70.70 (5) and 68.88 (3)°, respectively. The crystal packing is determined by weak non-classical hydrogen-bonding inter-actions. One carbonyl oxygen but not the other participates in C-H⋯O inter-actions zigzagging along the b axis, forming infinite chains. This is complemented by an intra-molecular C-H⋯S inter-action and further inter-molecular C-H⋯S (C-H⋯Se) inter-actions, resulting in a three-dimensional network. The inter-actions involving the bridging chalcogenides form chains protruding along the c axis.