High pressure phase transitions in BaWO4

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 similar to 7 +/- 0.3 GPa. Analysis of our data based on Le Bail refinement suggests that this phase could be fergusonite and not HgMoO4 type, which was proposed earlier from the Raman investigations. Beyond similar to 14 GPa, this compound undergoes another phase transformation to a significantly disordered structure. Both the phase transitions are found to be reversible. (C) 2004 Elsevier Ltd. All rights reserved.