Antimony(III) tellurium(IV) chloride trioxide SbTeO3Cl: synthesis and ab initio structure determination from X-ray and neutron powder diffraction data

The mixed chloride oxide SbTeO3Cl has been prepared in polycrystalline form by solvolysis reaction from SbCl3 and TeCl4. The X-ray and neutron powder diffraction patterns were indexed in an orthorhombic unit cell; the structure was partially solved in the space group Pnma from the X-ray data, and completed and refined from neutron data. The crystal consists of strongly covalent [SbTeO3]+ layers, perpendicular to the a axis, corrugated as a consequence of the electrostatic repulsion of the lone pairs of SbIII and TeIV. Both semimetals are three-fold co-ordinated to oxygens in pyramidal configuration. The layers are held together by discrete Cl– anions. This is one of the few examples of a positively charged two-dimensional network, very uncommon in the crystal chemistry of inorganic oxo compounds.