Hydrothermal synthesis and structure determination of the first three-dimensional oxyfluorinated gallium phosphate incorporating lithium

LiGa3F3(OH)(H2O)(2)(PO4)(2) was synthesised hydrothermally (453 K, 36 h, au togeneous pressure) from the mixture with molar composition 0.5 Ga2O3:0.5 P 2O5: 3 HF: 0.2 Li2O: 80 H2O. Its three-dimensional structure was solved, at 298 K, by single-crystal X-ray diffraction in the monoclinic space group P 2(1)/c (No. 14) with lattice parameters a = 8.6885(4) Angstrom, b = 8.2442( 4) Angstrom, c = 7.1303(4) Angstrom. beta = 104.351(2) Angstrom, V = 494.80 (4) Angstrom (3), Z = 2. Its structure consists of infinite double sheets, made from corner shared GaO3F{F2-x(OH)(x)} octahedra (x = 0, 1 or 2) and PO 4 tetrahedra of laueite-type chains, which are linked by GaO2F2(H2O)(2) oct ahedra to generate the framework encapsulating lithium cations. The OH/F su bstitution is discussed from solid state NMR results. (C) 2001 Editions sci entifiques et medicales Elsevier SAS. All rights reserved.