Crystal and molecular structure of polymeric tetraphenylarsonium bis(1,2-dicyanoethene-1,2-dithiolato)bismuthate(III)

Abstract

The crystal and molecular structure of the title compound, [AsPh₄][Bi{S₂C₂(CN)₂}₂], has been determined by single-crystal X-ray diffraction methods at ambient temperature and refined by least-squares procedures to a conventional residual of 0.085 for 2 648 observed reflections. Crystals are monoclinic, space group P2₁/n, with a= 16.06(4), b= 28.11(4), c= 7.389(6)Å, β= 98.16(10)°, and Z= 4. The structure comprises an infinite linear polymeric chain in which successive bismuth atoms are bridged by two dithiolene ligands, each ligand providing one bridging sulphur atom. The stereochemistry at the bismuth atom is either highly distorted octahedral with a stereochemically inactive lone pair or, more likely, distorted pentagonal bipyramidal with a stereochemically active lone pair occupying an equatorial position.