Although Goldschmidt tolerance aspects can semi-quantitatively forecast structural distortion on the basis of steric hindrance in 3D perovskites, It is far from easy to use to second perovskites, because the layered segregated constructions in 2nd perovskites enable the incorporation of greater natural and organic cations in to the inorganic cages26,27,28,29,30. https://crithitceramics.com/product/fireball/