Materials Data on UO3 by Materials Project

Abstract

UO3 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are five inequivalent U6+ sites. In the first U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share a cornercorner with one UO8 hexagonal bipyramid and corners with five UO6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of U–O bond distances ranging from 2.06–2.10 Å. In the second U6+ site, U6+ is bonded to eight O2- atoms to form UO8 hexagonal bipyramids that share corners with two equivalent UO8 hexagonal bipyramids, a cornercorner with one UO6 octahedra, and edges with two equivalent UO8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 1°. There are a spread of U–O bond distances ranging from 2.10–2.39 Å. In the third U6+ site, U6+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of U–O bond distances ranging from 1.94–2.72 Å. In the fourth U6+ site, U6+ is bonded to five O2- atoms to form distorted UO5 trigonal bipyramids that share a cornercorner with one UO6 octahedra and corners with four equivalent UO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 2°. There are a spread of U–O bond distances ranging from 2.06–2.21 Å. In the fifth U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with five UO6 octahedra and a cornercorner with one UO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of U–O bond distances ranging from 2.06–2.11 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to two U6+ atoms. In the second O2- site, O2- is bonded in a linear geometry to two U6+ atoms. In the third O2- site, O2- is bonded in a linear geometry to two U6+ atoms. In the fourth O2- site, O2- is bonded in a linear geometry to two U6+ atoms. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent U6+ atoms. In the sixth O2- site, O2- is bonded in a linear geometry to two equivalent U6+ atoms. In the seventh O2- site, O2- is bonded in a linear geometry to two equivalent U6+ atoms. In the eighth O2- site, O2- is bonded in a linear geometry to two equivalent U6+ atoms. In the ninth O2- site, O2- is bonded in a linear geometry to two equivalent U6+ atoms. In the tenth O2- site, O2- is bonded in a linear geometry to two equivalent U6+ atoms. In the eleventh O2- site, O2- is bonded in a linear geometry to two equivalent U6+ atoms. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent U6+ and one O2- atom. The O–O bond length is 1.48 Å. In the thirteenth O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent U6+ and one O2- atom. In the fourteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three U6+ atoms.