Crystal structure of the high-temperature protonic conductor SrCeO3

Abstract
The crystal structure of the perovskite-like high-temperature protonic conductor SrCeO3 has been studied with single-crystal and powder X-ray diffraction. SrCeO3 crystallizes in the orthorhombic space group Pbnm, Z= 4, with the unit-cell parameters a= 6.0117(4)Å, b= 6.1538(5)Å and c= 8.5886(9)Å. The structure was refined to a weighted R value of 0.0226 for the single-crystal data. The oxygen coordination around cerium is almost perfectly octahedral, whereas the SrO12 polyhedra are rather distorted. SrCeO3 is isostructural with another high-temperature protonic conductor, BaCeO3, but displays an appreciably higher degree of lattice distortion.