High temperature structure of BaBiO3—a synchrotron X-ray powder diffraction study

The structure of the valence ordered perovskite-like compound BaBiO3 has been studied at fine temperature intervals between room temperature and 923 K using high resolution synchrotron X-ray powder diffraction methods. The compound undergoes two structural phase transitions, a first order transition to a rhombohedral structure near 425 K and a second-order transition to a cubic structure, the transition temperature being estimated as 893 K.