Structure and Thermal Transformations of Methylammonium Tungstate

Methylammonium paradodecatungstate, (CH3NH3)10[H2W12O42] ? nH2O, was prepared by the reaction of WO3 or H2WO4 in aqueous methylamine, followed drying. The [H2W12O42]10? anion consists two HW3O13 groups containing three edge-sharing WO6 octahedra and W3O14 having connections. On drying produced material at 70 °C, some lattice water released, but this did not affect structure, although there a decrease unit cell volume. By adding water, loss structural changes were reversed. existence paradodecatungstate anions confirmed single-crystal powder X-ray diffraction, Fourier transform infrared, Raman, 183W nuclear magnetic resonance, ultraviolet-visible spectroscopy. When methylammonium heated to more than 150 CH3NH2 H2O amorphous observed as an intermediate product monoclinic final product. These results reveal structure tungstate, which first reported 1909 now is used important negative staining reagent for virus observation, paradodecatungstate.