High pressure phase transitions in BaWO<SUB>4</SUB>

Using in-situ angle dispersive X-ray diffraction, we have shown that barium tungstate, which exists in scheelite phase at ambient conditions, transforms to a new phase at ~7± 0.3 GPa. Analysis of our data based on Le Bail refinement suggests that this phase could be fergusonite and not HgMoO<SUB>4</SUB> type, which was proposed earlier from the Raman investigations. Beyond ~14 GPa, this compound undergoes another phase transformation to a significantly disordered structure. Both the phase transitions are found to be reversible