Materials Data on Ce3TaO7 by Materials Project

Abstract

Ce3TaO7 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Ce3+ sites. In the first Ce3+ site, Ce3+ is bonded to seven O2- atoms to form distorted CeO7 pentagonal bipyramids that share corners with two equivalent TaO6 octahedra, corners with three equivalent CeO7 pentagonal bipyramids, edges with two equivalent TaO6 octahedra, and edges with two equivalent CeO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 38°. There are a spread of Ce–O bond distances ranging from 2.30–2.71 Å. In the second Ce3+ site, Ce3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.42 Å) and four longer (2.73 Å) Ce–O bond lengths. Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra, corners with four equivalent CeO7 pentagonal bipyramids, and edges with four equivalent CeO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 31°. There are two shorter (2.00 Å) and four longer (2.03 Å) Ta–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four Ce3+ atoms to form a mixture of edge and corner-sharing OCe4 tetrahedra. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Ce3+ and one Ta5+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ce3+ and two equivalent Ta5+ atoms.