Crystal structure of an Hg coordination polymer with an unsymmetrical dipyridyl ligand: -poly[[[di-chlorido-mercury(II)]-μ--(pyridin-4-ylmeth-yl)pyridin-3-amine-κ:'] chloro-form hemisolvate].

The asymmetric unit of the title compound, {[HgCl]·0.5CHCl} ( = -(pyridin-4-ylmeth-yl)pyridin-3-amine, CHN), contains one Hg ion, one bridging ligand, two chloride ligands and a chloro-form solvent mol-ecule with half-occupancy that is disordered about a crystallographic twofold rotation axis. Each Hg ion is coordinated by two pyridine N atoms from two symmetry-related ligands and two chloride anions in a highly distorted tetra-hedral geometry with bond angles falling in the range 99.05 (17)-142.96 (7)°. Each ligand bridges two Hg ions, forming polymeric zigzag chains propagating in [010]. In the crystal, the chains are linked by inter-molecular N/C-H⋯Cl hydrogen bonds together with weak C-H⋯π inter-actions, resulting in the formation of a three-dimensional supra-molecular network, which is further stabilized by C-Cl⋯π inter-actions between the solvent chloro-form mol-ecules and the pyridine rings of [chloride-to-centroid distances = 3.442 (11) and 3.626 (13) Å]. In addition, weak Cl⋯Cl contacts [3.320 (5) Å] between the chloro-form solvent mol-ecules and the coordinating chloride anions are also observed.