CRYSTAL-STRUCTURES OF ANTIMONY AND INDIUM PHOSPHINODITHIOATES, M(S(2)PR(2))(3) (M=SB, R=ET, M=IN, R=ME, PH) - IS THE LONE-PAIR RESPONSIBLE FOR THE STRUCTURAL DIFFERENCES

The molecular structures of Sb(S(2)PEt(2))(3) and In(S(2)PR(2))(3), R = Me and Ph, have been determined by single crystal X-ray diffraction. Both types of compound display distorted octahedral coordination geometry. In the antimony(III) compound the ligand is anisobidentate (unsymmetric) whereas in the indium compounds the coordinated ligands are basically isobidentate (symmetric). The distortions of the geometry are caused by the small bite of the ligands. An attempt is made to rationalize the structural differences observed without invoking lone pair stereochemical activity in the antimony(III) compound.