Bis(N,N′-dimethylimidazol-2-yl­idene)mercury chlorotriiodo­mercury dimethyl sulfoxide solvate

The double mercury salt [Hg(C5H8N2)2][HgClI3]·C2H6OS was prepared and its structure characterized. The [Hg(C5H8N2)2]2+ cation lies about an inversion centre and the [HgClI3]2− anion lies on a mirror plane. Cations and anions are linked to form a one-dimensional polymer by weak Hg⋯Cl interactions [Hg⋯Cl 3.3744 (3) A]. The mercury–carbene bond distance [2.076 (7) A] is typical of a dicationic mercury–carbene species.