(2-{[4-(Chlorido-mercur-yl)phen-yl]imino-meth-yl}pyridine-κ(2) N,N')di-iodido-mercury(II) dimethyl sulfoxide monosolvate.

The title dimethyl sulfoxide solvate, [Hg2(C12H9ClN2)I2]·C2H6OS, features tetra-hedrally and linearly coordinated Hg(II) atoms. The distorted tetrahedral coordination sphere is defined by chelating N atoms that define an acute angle [69.6 (3)°] and two I atoms that form a wide angle [142.80 (4)°]. The linearly coordinated Hg(II) atom [177.0 (4)°] exists with a donor set defined by C and Cl atoms. Secondary inter-actions are apparent in the crystal packing with the tetra-hedrally and linearly coordinated Hg(II) atoms expanding their coordination environments by forming weak Hg⋯I [3.772 (7) Å] and Hg⋯O [2.921 (12) Å] inter-actions, respectively. Mercury-containing mol-ecules stack along the a axis, are connected by π-π inter-actions [inter-centroid distance between pyridine and benzene rings = 3.772 (7) Å] and define channels in which the dimethyl sulfoxide mol-ecules reside. The latter are connected by the aforementioned Hg⋯O inter-actions as well as C-H⋯I and C-H⋯O inter-actions, resulting in a three-dimensional architecture.