Crystal structure of hexakis(triphenylphosphine oxide)dimercury(I) bisperchlorate

Abstract

The title compound has been prepared and its crystal structure determined by single-crystal X-ray diffraction methods. The structure was solved by Patterson and Fourier methods and refined by block-diagonal least-squares methods to R 0·12 for 1696 independent visually estimated reflections. Crystals are triclinic, space group Pa= 12·55(1), b= 14·47(2), c= 16·05(2)Å, α= 120·0(1), β= 82·3(1), γ= 95·2(1)°. There is one dimeric unit in the cell, the best formulation being [(Ph₃PO)₃Hg–Hg(Ph₃PO)₃][ClO₄]₂. Hg–Hg is 2·522(2)Å. The centrosymmetric cationic species is discrete and the mercury environment approximately tetrahedral (Hg–O 2·29–2·43 Å); there is an inverse correlation between the Hg–O distance and the Hg–Hg–O angle. The perchlorate ion is subject to high thermal motion and is ill-defined; the Ph₃PO geometries are as expected.