“…During the last decade, intensive investigations have been carried out on the structural evolution of the zircon-type vanadates under extreme conditions. In particular, x-ray diffraction [3 -6], optical [7,8], and Raman scattering measurements [4,6,8,9,10], and theoretical calculations [5,6,10,11] have been carried out to understand the structural modifications induced by pressure. Orthovanadates with small A cations have been observed to undergo an irreversible zircon-to-scheelite (space group: I4 1 /a, Z = 4) phase transition [3].…”