Room temperature angle-dispersive x-ray diffraction measurements on zircontype EuVO 4 , LuVO 4 , and ScVO 4 were performed up to 27 GPa. In the three compounds we found evidence of a pressure-induced structural phase transformation from zircon to a scheelite-type structure. The onset of the transition is near 8 GPa, but the transition is sluggish and the low-and high-pressure phases coexist in a pressure range of about 10 GPa. In EuVO 4 and LuVO 4 a second transition to a M-fergusonite-type phase was found near 21 GPa. The equations of state for the zircon and scheelite phases are also determined. Among the three studied compounds, we found that ScVO 4 is less compressible than EuVO 4 and LuVO 4 , being the most incompressible orthovanadate studied to date. The sequence of structural transitions and compressibilities are discussed in comparison with other zircon-type oxides.

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Room temperature angle-dispersive x-ray diffraction measurements on zircon-type TbVO 4 and CeVO 4 were performed in a diamond-anvil cell up to 50 GPa using neon as pressure-transmitting medium. In TbVO 4 we found at 6.4 GPa evidence of a non-reversible pressure-induced structural phase transition from zircon to a scheelite-type structure. A second transition to an M-fergusonite-type structure was found at 33.9 GPa, which is reversible. Zircon-type CeVO 4 exhibits two pressureinduced transitions. First an irreversible transition to a monazite-type structure at 5.6GPa and second at 14.7 GPa a reversible transition to an orthorhombic structure. No additional phase transitions or evidences of chemical decomposition are found in the experiments. The equations of state and axial compressibility for the different phases are also determined. Finally, the sequence of structural transitions and the compressibilities are discussed in comparison with other orhtovanadates and the influence of non-hydrostaticity commented.

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