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 140oC. 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) A, b 7.1024(15) A, c = 13.391(3) A, β = 104.250(2)o. The structure of Nd2(SeO4)(SeO3)2(H2O)2 is isomorphous with that of Er2(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