SYNTHESIS AND STRUCTURE OF KIN(OH)PO4 - CHAINS OF HYDROXIDE-BRIDGED INO4(OH)(2) OCTAHEDRA

The new compound KIn(OH)PO4 was prepared by hydrothermal reaction of I n2O3 and K2HPO4 at 900 degrees C and 3 kbar pressure with subsequent s low cooling. Single-crystal X-ray data for KIn(OH)PO4: orthorhombic, a = 9.277(2) Angstrom, b 9.339(2) Angstrom, c = 11.245(2) Angstrom, spa ce group P2(1)2(1)2(1), Z = 8, R = 2.64, R(w) = 2.92%, The compound is built of cis-InO4(OH)(2) octahedra that form spiral chains, parallel to the c axis, by corner-sharing of the OH groups, The chains are inte rconnected by phosphate tetrahedra in a manner that creates tunnels al ong the z direction containing the K ions. KIn(OH)PO4 is related in st ructure to the gamma phase of NaTiOPO4. The title compound does not ge nerate an SHG signal, TGA and Guinier X-ray powder diffraction data ar e also reported. (C) 1996 Academic Press, Inc.