High-pressure Raman study of Al2(WO4)3

A high-pressure Raman scattering study of the tungstate Al2(WO4)3 is presented. This study showed the onset of two reversible phase transitions at 0.28±0.07 and 2.8±0.1 GPa. The pressure evolution of Raman bands provides strong evidences that both the transitions involve rotations/tilts of nearly rigid tungstate tetrahedra and that the structure of the stable phase in the 0.28–2.8 GPa range may be the same as the structure of the ambient pressure, low-temperature monoclinic (C2h5) ferroelastic phase of Al2(WO4)3.