Lone Pairs as Chemical Scissors in New Antimony Oxychlorides, Sb2ZnO3Cl2 and Sb16Cd8O25Cl14

Abstract

Two new metal antimony oxychlorides, Sb2ZnO3Cl2 and Sb16Cd8O25Cl14, have been synthesized by solid-state reactions using Sb2O3 and ZnCl2 (or CdCl2) as reagents. The structures of Sb2ZnO3Cl2 and Sb16Cd8O25Cl14 have been determined by single-crystal X-ray diffraction. Both of the reported materials contain Sb3+ cations that are in an asymmetric coordination environment attributable to their stereoactive lone pair. Sb2ZnO3Cl2 has a novel two-dimensional layered structure consisting of distorted ZnO2Cl2 tetrahedra and SbO3 polyhedra. Sb16Cd8O25Cl14 exhibits a one-dimensional structure consisting of Sb3+-Cd2+-oxide rods, Cd2+-chloride double chains, and isolated Cl- ions. Complete separation of the halophile and chalcophile moieties is observed from the reported materials. Detailed structural analysis, IR spectra, thermogravimetric analysis, ion-exchange reactions, and dipole moment calculations are presented. Crystal data: Sb2ZnO3Cl2, orthorhombic, space group Pnma (No. 62), a = 17.124(4) angstrom, b = 5.5598(12) angstrom, c = 6.4823(14) angstrom, V = 617.2(2) angstrom(3), and Z = 4; Sb16Cd8O25Cl14, monoclinic, space group I2/m (No. 12), a = 14.251(3) angstrom, b = 3.9895(8) angstrom, C = 21.145(4) angstrom, beta = 97.35(3)degrees, V = 1192.3(4) angstrom(3), and Z = 8.