Raman Spectra of Molybednum Phosphate Glasses and Some Crystalline Analogues

The Raman spectra of a series of glasses in the system MoO 3 ‐P 2 O 5 and the polyerystalline compounds molybdenum metaphosphate (MoO 2 (P0 3 ) 2 ) and molybdenum pyrophosphate ((MoO 2 ) 2 P 2 O 2 ) are reported. The spectra indicate that traces of P=O and phosphate chains are present only in glasses having less than 50 mol% MoO 3 . Comparison of the glass spectra with spectra of crystalline molybdenum phosphates indicates the presence of metaphosphate and orthophosphate structural groups of MoO 3 concentrations of about 50 mol% or less. As the MoO 3 concentration is increased, the bands characteristic of pyrophosphate groups appear in the spectra and become the dominant feature at 76 mol% MoO 3 concentration. Metaphosphate groups are present in the glass even at the highest MoO 3 concentrations measured.