{N(1)-[2-(Butyl-selan-yl)benz-yl]-N(2),N(2)-di-methyl-ethane-1,2-di-amine}-dichlorido-mercury(II).

In the title compound, [HgCl(2)(C(16)H(28)N(2)Se)], the primary geometry around the Se and Hg atoms is distorted trigonal-pyramidal and distorted square-pyramidal, respectively. The distortion of the mol-ecular geometry in the complex is caused by the steric demands of the ligands attached to the Se atom. The Hg atom is coordinated through two chloride anions, an N atom and an Se atom, making up an unusual HgNSeCl(2) coordination sphere with an additional long Hg⋯N inter-action. Inter-molecular C-H⋯Cl inter-actions are the only identified inter-molecular hydrogen-bonding inter-actions that seem to be responsible for the self assembly. These relatively weak C-H⋯Cl hydrogen bonds possess the required linearity and donor-acceptor distances. They act as mol-ecular associative forces that result in a supra-molecular assembly along the b-axis direction in the solid state of the title compound.