Estimation of polyhedral compressibilities and structural evolution of GdFeO3- type perovskites at high pressures

A new approach based on the bond-valence matching relation is developed to predict the detailed structural evolution of GdFeO3-type perovskites at high pressure from knowledge of the room-pressure structure and the high-pressure unit-cell parameters alone. The evolution of perovskite structures estimated in this way is in good agreement with the structure refinements available from high-pressure single-crystal diffraction measurements of a number of perovskites. The method is then extended to predict the structure of MgSiO3 perovskite at pressures for which no single-crystal structural data are available and the results are compared to ab initio quantum calculations of MgSi3 perovskite up to 120 GPa.