Prediction of lattice constant in cubic perovskites

Regularities of lattice constant in ideal perovskites are investigated by using a total of 132 ABX₃-type compounds, including oxides and halides. Two atomic properties; the sum of ionic radius of B and X atoms and the well known ‘tolerance factor’ (which is a function of ionic radius of A, B and X), were found very effective in reproducing the measured lattice constant through a linear combination of these two parameters (R²=0.995). It is further indicated that these two parameters are linked to the crystal features of perovskite. The average error limits in predicting lattice constant, by using this empirical equation, are expected within 0.63%. It may be useful to design new substrates/buffer materials for compound semiconductor epitaxy, in which there is a requirement of lattice match between them and adjacent layers.