ABSTRACT
This chapter provides a description of the single perovskite structure and possible structural distortions caused by octahedral tilting, B-cation displacement, and Jahn–Teller distortion. The tolerance factor gives a rough estimate on the structure of perovskite crystals, and it is valuable in predicting the structure of perovskite oxides, as the ionic radius of the metallic ions is well-known. The perovskite structure is composed of corner-sharing octahedral network, and the main axis of the tilt can be parallel to each crystallographic axis. The structure of perovskite often deviates from the cubic structure based on several parameters such as the size and oxidation state of the cations, temperature, pressure, and synthetic route. The crystal structure of perovskites can be well studied by neutron, X-ray, or electron diffraction techniques at different temperatures to monitor the crystal structural changes, especially the electron microscopy provides imaging capabilities to study the microstructure during the phase transitions.
