Materials Data on Ba4Ce2O7 by Materials Project

Abstract

Ba4Ce2O7 crystallizes in the orthorhombic Cmce space group. The structure is three-dimensional. Ba2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ba–O bond distances ranging from 2.62–3.26 Å. Ce3+ is bonded to five O2- atoms to form corner-sharing CeO5 square pyramids. There are a spread of Ce–O bond distances ranging from 2.21–2.31 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to five equivalent Ba2+ and one Ce3+ atom to form distorted OBa5Ce octahedra that share corners with eight OBa5Ce octahedra, corners with three equivalent OBa2Ce2 tetrahedra, edges with eight equivalent OBa5Ce octahedra, edges with two equivalent OBa2Ce2 tetrahedra, and a faceface with one OBa4Ce2 octahedra. The corner-sharing octahedra tilt angles range from 4–62°. In the second O2- site, O2- is bonded to four equivalent Ba2+ and two equivalent Ce3+ atoms to form distorted OBa4Ce2 octahedra that share corners with twelve equivalent OBa5Ce octahedra, corners with four equivalent OBa2Ce2 tetrahedra, edges with two equivalent OBa2Ce2 tetrahedra, and faces with four equivalent OBa5Ce octahedra. The corner-sharing octahedra tilt angles range from 40–62°. In the third O2- site, O2- is bonded to two equivalent Ba2+ and two equivalent Ce3+ atoms to form distorted OBa2Ce2 tetrahedra that share corners with eight OBa5Ce octahedra, corners with two equivalent OBa2Ce2 tetrahedra, and edges with five OBa5Ce octahedra. The corner-sharing octahedra tilt angles range from 18–75°.