First principles study of Ca2PtO4 in K2NiF4 and 'post-K2NiF4' type structures

► Transformations of 3D perovskite (pv) to 2D post-perovskite ppv (ABO3) with pressure P are known. ►We propose in parallel the K2NiF4-type (knf) as a potential low P form of Ca2IrO4-type (pknf). ►P-transformation of 2D corner sharing octahedra (knf) to 1D edge sharing octahedra (pknf). ►Argumentation based on DFT computations of equation of state, charge density; DOS for Ca2PtO4 case.