Structural chemistry of (PPh4)2M(WS4)2 materials

Abstract

In this paper we discuss the structural chemistry of (PPh₄)₂M(WS₄)₂ (M = Co, Ni, Zn) materials. For M = Ni we and others have been unable to grow single crystals and we report the structure determination from powder diffraction. The material is triclinic (P, a = 9.3730(2), b = 12.4951(3), c = 12.5189(3) Å, α = 65.814(1), β = 83.751(1), γ = 69.571(1)° at T = 293 K). It contains square-planar coordination around Ni. For M = Zn we have isolated two polymorphs. We describe new analysis of the complex superstructure and diffuse scattering observed in the tetragonal polymorph (I, a = 18.723(4), c = 13.563(4) Å at T = 120 K) and the bulk preparation of a monoclinic (P2₁/c, a = 18.6397(4), b = 15.3693(5), c = 18.9822(5) Å, β = 109.239(2)° at T = 293 K) polymorph isostructural with the M = Co material.