Raman and i.r.-emission studies of some tungstate- and molybdate-containing melts

Melts containing tungstate and molybdate ions have been studied using Raman and i.r.-emission spectroscopy. Vibrational data obtained for Mo16O42-- and Mo18O42-- containing melts firmly support a tetrahedral structure for MoO42- (and by implication for WO42-as well) and establish the correct assignment of ν2 and ν4 for this species. Acidification of these MoO42- and WO42- melts by addition of the corresponding metal trioxides produced no significant change in the observed spectra, although significant solubilities of the trioxides in the WO42- and MoO42- melts were observed. (author)