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.