Revised method for the prediction of lattice constants in cubic and pseudocubic perovskites

The correlation between ionic radii and the lattice constants of cubic/pseudocubic perovskites is re-examined and a new empirical formula for the relationship is derived. The average absolute error in the predicted lattice constants of perovskites thus derived is expected to be about 0.60%. Discrepancies between measured lattice constants and those calculated from idealized structural models are shown to be due to stretching or compression of bond lengths and are strongly correlated to both tolerance factor and cation bond valence sums. The formula derived may be useful in the engineering of substrates or buffer layers for heteroepitaxial films, in which a lattice match is essential.