Whilst Goldschmidt tolerance things can semi-quantitatively forecast structural distortion on The premise of steric hindrance in 3D perovskites, It's not at all easy to use to 2D perovskites, as the layered segregated structures in second perovskites enable the incorporation of bigger natural and organic cations to the inorganic cages26,27,28,29,30. The https://crithitceramics.com/product/fireball/