High-Pressure Single-Crystal X-Ray Diffraction Study of ErVO4

We present an investigation into the crystal structure of ErVO₄ under variable pressure conditions. The high-pressure single-crystal X-ray diffraction experiments performed employing helium as the pressure medium facilitated structure refinements up to 24.1(2) GPa. The transition from zircon to scheelite was observed at a pressure of 7.9(1) GPa. In contrast to previous reports, we did not detect any sign of phase coexistence. We also did not observe the second phase transitions previously predicted by density-functional theory to occur below 20 GPa. The determination of the pressure dependence of unit-cell parameters and volume yields precise values for the linear compressibility of each axis and the pressure–volume equation of state for both the zircon and scheelite phases. Additional information on the mechanical properties of ErVO₄, obtained from density-functional theory calculations, is also reported.