Study of monazite under high pressure

Monazite was studied under high pressures of up to 20 GPa and 12 GPa by using synchrotron X-ray diffraction and Raman spectroscopy, respectively. X-ray diffraction data suggested that there was a structural distortion at ∼11.5 GPa. The pressure–volume data of the monazite was fitted to a third-order Birch–Murnaghan equation of state and yielded a bulk modulus of 109(1) GPa and a pressure derivative of 6.7(1), in agreement with an empirical formula.