Empirical model for the prediction of lattice constants in 1:2 ordered perovskites

Processing–structure relationships are at the heart of materials science, and predictive tools are essential for modern technological industries insofar as structure dictates intrinsic properties; however, few theoretical models exist for cation-ordered perovskites. In this work, a combination of data mining and solid-state synthesis was employed to collect structural data of 1:2 ordered (triple) perovskites. Three compositions within the (Ba_1 −xSr_x)(Mg_1/3Ta_2/3)O₃ system were synthesized using a conventional solid-state mixed-oxide method. X-ray diffraction data showed evidence of long-range 1:2 B-site cation ordering for all compositions. Additional data for another 24 1:2 ordered compositions were mined from literature. Correlative models for the deviation in modified tolerance factor (Δt′) were derived for each system, and a general model which is capable of predicting the pseudocubic lattice constants of such perovskites based solely on published ionic-radii data developed.