Materials Data on CsU2O6 by Materials Project

Abstract

CsU2O6 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Cs–O bond distances ranging from 3.28–3.61 Å. In the second Cs1+ site, Cs1+ is bonded to six O2- atoms to form distorted CsO6 octahedra that share corners with six UO6 octahedra and corners with six equivalent UO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 66–71°. There are three shorter (3.11 Å) and three longer (3.16 Å) Cs–O bond lengths. There are four inequivalent U+5.50+ sites. In the first U+5.50+ site, U+5.50+ is bonded to six equivalent O2- atoms to form corner-sharing UO6 octahedra. The corner-sharing octahedral tilt angles are 42°. All U–O bond lengths are 2.12 Å. In the second U+5.50+ site, U+5.50+ is bonded to seven O2- atoms to form distorted UO7 pentagonal bipyramids that share corners with two equivalent CsO6 octahedra, corners with three UO6 octahedra, an edgeedge with one UO6 octahedra, and edges with two equivalent UO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 35–63°. There are a spread of U–O bond distances ranging from 1.94–2.47 Å. In the third U+5.50+ site, U+5.50+ is bonded to six O2- atoms to form UO6 octahedra that share a cornercorner with one CsO6 octahedra, corners with four UO6 octahedra, and corners with two equivalent UO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 39–71°. There are a spread of U–O bond distances ranging from 2.00–2.30 Å. In the fourth U+5.50+ site, U+5.50+ is bonded to six O2- atoms to form UO6 octahedra that share corners with two equivalent CsO6 octahedra, corners with two equivalent UO6 octahedra, corners with two equivalent UO7 pentagonal bipyramids, and edges with two equivalent UO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 47–66°. There are a spread of U–O bond distances ranging from 1.99–2.19 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two Cs1+ and two U+5.50+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Cs1+ and two U+5.50+ atoms. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two Cs1+ and two equivalent U+5.50+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+ and two U+5.50+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+ and two U+5.50+ atoms. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cs1+ and two equivalent U+5.50+ atoms. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to three U+5.50+ atoms. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cs1+ and two U+5.50+ atoms.