Synthesis and Crystal Structure of the Octahedral—Tetrahedral Framework Indium Phosphate Cs[In2(PO4)(HPO4)2(H2O)2

Abstract

The reaction of InCl3, H3PO4, CsVO3, TMAOH (tetramethyl ammonium hydroxide), and H2O in the molar ratios 2:6:1:1:125 under hydrothermal conditions at 200°C for 2 days yielded pale yellow crystals of Cs[In2(PO4)(HPO4)2(H2O)2] (1). Phosphate (1) crystallizes in the monoclinic space group P 21/c (No. 14) with a = 6.580(2) Å, b = 18.092(1) Å, c = 10.180(1) Å β = 97.92(2)°, V = 1200.2(4) Å3, Z = 4, and Dcal = 3.76 g cm-3; R/Rw = 0.036/0.044 for 2855 reflections with 2θ < 60.1° and I ≥ 3σ(I). The framework consists of corner-sharing indium octahedra and phosphate tetrahedra that form one-dimensional ribbons extending down the c axis, parallel to the crystallographic (100) plane, which interconnect to form the three-dimensional structure. The framework has large cavities in which the Cs+ cations reside.