Synthesis and crystal structure of a new neodymium(III) selenate-selenite:: Nd2(SeO4)(SeO3)2(H2O)2

The title new neodymium(III) selenate-selenite was obtained by hydrothermal reactions of neodymium(III) oxide, H2SeO4 and 1,10-phenanthroline at 140degreesC. Its structure was established by single-crystal X-ray diffraction. The title compound crystallizes in the monoclinic space group C2/c with cell parameters of a = 12.258(2) Angstrom, b = 7.1024(15) Angstrom, c = 13.391(3) Angstrom, beta = 104.250(2)degrees. The structure of Nd-2(SeO4)(SeO3)(2)(H2O)(2) is isomorphous with that of Er-2(SeO4)(SeO3)(2)(H2O)(2), which was refined in the monoclinic space group C2 with the disordered selenate group. It features an ordered 3D network with channels along b-axis. The selenate or selenite groups alone can form a 2D layer with the Nd(III) ions. IR spectrum, TGA and luminescent studies have also been performed. (C) 2004 Elsevier B.V. All rights reserved.