A Vanadium Tellurate, (NH4)2[VO2]2[TeO4(OH)2], Containing Two Edge-Shared Square-Pyramidal VO5 Groups

A new ammonium vanadium tellurate, (NH4)(2)[VO2](2)[TeO4(OH)(2)] (1), was hydrothermally synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, and TG analysis. Compound 1 crystallizes in the monoclinic system, space group P2(1)/n: a=8.9112(18) angstrom, b=15.151(3) angstrom, c=15.187(3) angstrom, beta=97.91(3)degrees, V=2030.9(7) angstrom(3), Z=8, R1 (l > 2 sigma(l))=0.0295, wR2 (all data)=0.0631. The structure of 1 consists of infinite anionic chains, {[VO2](2)[TeO4(OH)(2)]}(2-), of edge-sharing VO5 square pyramids and TeO4(OH)(2) octahedra. Two VO5 square pyramids are joined together by sharing their edge to form a V2O8 binuclear unit, The V2O8 and TeO4(OH)(2) units are alternatively connected to each other by sharing their edges to complete infinite zigzag anionic {[VO2](2)[TeO4(OH)(2)]}(2-) chains. The structure contains an extended network of O-H center dot center dot center dot O hydrogen bonds between the chains. The network of intermolecular hydrogen bonding results in layers parallel to the ab plane. Ammonium cations are hydrogen-bonded either to the oxygen atoms of the anionic chains or to each other in a complex arrangement.