Redetermination of poly[μ-chlorido-heptachlorido-μ3-l-proline-μ2-l-proline-tetramercury(II)]

Abstract

The asymmetric unit of the title compound, [Hg4Cl8(C5H9NO2)2]n, consists of four HgCl2 units and two L-proline ligands in the zwitterionic form. In each HgCl2 unit, the HgII ion is strongly bonded to two Cl atoms, and the HgII ions in two of the HgCl2 units are chelated by O atoms of two l-proline ligands, with one strong and one weak Hg—O bond. In the crystal structure, HgCl2 and L-proline units are linked to form an extended chain along the a axis. The chain structure is further stabilized by N—H...Cl hydrogen bonds, and the chains are arranged in layers parallel to the ab plane. The structure of the title compound was originally determined by Ehsan, Malik & Haider [(1996). J. Banglad. Acad. Sci. 20, 175] but no three-dimensional coordinates are available.