HYDROTHERMAL SYNTHESIS AND CRYSTAL-STRUCTURE OF CAIN2(PO4)(2)(HPO4) -AN OCTAHEDRAL TETRAHEDRAL FRAMEWORK TERNARY CALCIUM INDIUM(III) PHOSPHATE

The new ternary calcium indium(III) phosphate CaIn2(PO4)(2)(HPO4) With mixed octahedral-tetrahedral framework was synthesized through hydrot hermal reaction of stoichiometric amounts of CaO and InCl3 with excess of H3PO4 and H2O at pH = 1. Single crystal x-ray diffraction studies show the compound to crystallize in monoclinic symmetry, space group P 2(1)/n (#14) with a = 657.08(6), b = 2023.7(2), c = 665.72(7) pm, beta = 91.20(1)degrees, Z = 4 and R = 0.043. The framework is built up of dimers of edge-sharing InO6 octahedra forming In2O10 units sharing all their oxo ligands with PO4 tetrahedra, and HPO4 groups.