Predicting and Screening Dielectric Transitions in a Series of Hybrid Organic–Inorganic Double Perovskites via an Extended Tolerance Factor Approach

Extended Goldschmidt tolerance factor t is applied to the hybrid double perovskites (MA) 2 [B′B′′(CN) 6 ] (MA=methylammonium cation) to predict and screen dielectric transitions in 121 compounds through the correlations among t, the radius of the B component r B and the transition temperature T c , based on experimental results from model compounds. For (MA) 2 [B′Co(CN) 6 ], it is concluded that: i) when t>0.873, the cubic phase would be stable below 298 K; ii) when 0.873>t>0.805, the cubic phase would be stable between 298 and 523 K; iii) the larger the r B , the higher the T c of the perovskite (T c 1/2 ∝r B ); and iv) the T c of the hybrid perovskites can be well tuned by doping the B components.