Synthesis and structure characterization of two new lithium-heptamolybdates

Abstract

The synthesis, crystal structures, IR, UV-Vis, 7Li NMR spectra, electrochemical investigations and conductivity studies of two new lithium-heptamolybdates, (NH4)4[Li2(H2O)7][Mo7O24].H2O (1) and (NH4)3[Li3(H2O)4(?6-Mo7O24)].2H2O (2), are reported. In 1 the (NH4) sup(+) and [Li2(H2O)7] sup(2+) cations are charge balanced by the heptamolybdate anion. In 2 the [Mo7O24] sup(6-) anion is coordinated to three unique Li sup(+) ions via a mu6-hexadentate binding mode resulting in the formation of a two-dimensional (2-D) [Li3(H2O)4(mu6-Mo7O24)] sup(3-) anionic complex, charge neutralized by three (NH4) sup(+) ions. The cations, anions and the lattice water molecules in 1 and 2 are linked by weak H-bonding interactions.