X-Ray crystal structure identification of the ternary complex MgCl2·2SbCl3·6MeCN

Abstract

The solid-state structure of MgCl₂·2SbCl₃·6MeCN has been determined by X-ray diffraction studies as the ionic salt [Mg(MeCN)₆][(SbCl₄)₂]. Crystals of hexakis(acetonitrile)magnesium(II) bis[tetrachloroantimonate(III)] are triclinic, space group P with a= 8.968(8), b= 10.220(11), c= 8.389(9)Å, α= 97.1(1), β= 79.8(1), γ= 78.1(1)°, and Z= 1.2 165 Independent reflections above background have been measured on a diffractometer and the structure refined to R 0.070. In the centrosymmetric [Mg(MeCN)₆]²⁺ cation, the six-co-ordinate magnesium atom has a regular octahedral geometry with independent Mg–N distances of 2.136(9), 2.134(7), and 2.179(8)Å. The [SbCl₄]^– units are polymeric. There are three short Sb–Cl bonds in a fac arrangement [Sb–Cl(1) 2.433(2), Sb–Cl(3) 2.431(2), Sb–Cl(4) 2.367(3)Å]. Two SbCl₃ moieties are bridged via two weaker bonds [Sb–Cl(2) 3.006(3), Sb–Cl(2′) 2.822(4)Å] over a centre of symmetry to give [Sb₂Cl₈]^2– units. These units are connected via a further weak contact Sb–Cl(1″) 3.580(2)Å to give a polymeric chain. The environment of the antimony atom is distorted octahedral and there is no evidence for a stereochemically active lone pair of electrons around the antimony centres.