Wu, X (reprint author), Chinese Acad Sci, Inst High Energy Phys, Beijing Synchrotron Radiat Facil, Beijing 100039, Peoples R China.
Perovskite type compounds of general formula ABX(3) have the most commonly adopted structure (Pbnm), to some extent distorted front the ideal structure Pm3m. Their structures transformations are diverse at high pressure. Three parameters ( t, V-A/V-B, E-tot), which are used to describe the stabilization of perovskite structures, are introduced briefly. Applied three parameters, all models of perovskite structure ( Pbnm) changing at high pressure are summed up. Some of the models suit all perovskites structures. As an example, CaTiO3 (Pbnm) structure changing at high pressure is analyzed by applying several models and qualitatively draws a conclusion that the structure symmetry is reduced with enhancing the pressure.