catena-Poly[[chloridomercury(II)]-μ-1,4-diaza-bicyclo-[2.2.2]octane-κN:N'-[chlorido-mercury(II)]-di-μ-chlorido].

In the title coordination polymer, [Hg(2)Cl(4)(C(6)H(12)N(2))](n), each Hg(II) center within the chain is four-coordinated by one terminal Cl atom, two bridging μ(2)-Cl atoms, and one N-atom donor from a μ(2)-1,4-diaza-bicyclo-[2.2.2]octane (μ(2)-daco) ligand in a distorted tetra-hedral geometry. The daco ligand acts as an end-to-end bridging ligand and bridges adjacent Hg(II) centers, forming a chain running along [001]. Weak C-H⋯Cl hydrogen-bonding inter-actions link the chains into a three-dimensional network. Comparison of the structural differences with previous findings suggests that the space between the two N donors, as well as the skeletal rigidity in N-heterocyclic linear ligands, may play an important role in the construction of such supra-molecular networks.