Chinese Acad Sci, Inst High Energy Phys, Beijing Synchrotron Radiat Facil, Beijing 100039, Peoples R China
; Peking Univ, Dept Geol, Beijing 100871, Peoples R China
In situ high-pressure (up to 44.53 GPa) energy dispersive x-ray diffraction experiments have been carried out on CaTiO3 in a diamond anvil cell at room temperature by using synchrotron radiation. Experimental data show that the a and b axes have similar compressibilities with large variation, while the c axis is less compressible with increasing pressure. However, there is no evidence of any structural transformation in this pressure range. The isothermal P-V equation of the state of CaTiO3 is fitted using the Murnaghan equation of state, which yields values of V-0 = 0.2245 (6) nm(3) and K-0 = 222 (9) GPa assuming the pressure derivative K'(0) = 4. According to the relation of the pseudo-cubic angle gamma(pc), and pressure, the structure of CaTiO3 will reduce its symmetry under hydrostatic pressure.