Materials Data on Ca3UO6 by Materials Project

Abstract

Ca3UO6 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.35–2.87 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six equivalent UO6 octahedra. The corner-sharing octahedra tilt angles range from 36–45°. There are a spread of Ca–O bond distances ranging from 2.30–2.43 Å. U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six equivalent CaO6 octahedra. The corner-sharing octahedra tilt angles range from 36–45°. There are two shorter (2.07 Å) and four longer (2.11 Å) U–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to three Ca2+ and one U6+ atom to form a mixture of distorted corner and edge-sharing OCa3U tetrahedra. In the second O2- site, O2- is bonded in a 5-coordinate geometry to four Ca2+ and one U6+ atom. In the third O2- site, O2- is bonded to three Ca2+ and one U6+ atom to form a mixture of distorted corner and edge-sharing OCa3U trigonal pyramids.