DOI: 10.17188/1276860
title: Materials Data on Cs2U(SiO4)2 by Materials Project

description: Cs2U(SiO4)2 crystallizes in the orthorhombic Ibca space group. The structure is three-dimensional. there are four 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 3.07–3.66 Å. In the second Cs1+ site, Cs1+ is bonded to six O2- atoms to form distorted CsO6 octahedra that share corners with two equivalent UO6 octahedra, corners with four SiO4 tetrahedra, and edges with two equivalent UO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Cs–O bond distances ranging from 2.95–3.33 Å. In the third Cs1+ site, Cs1+ is bonded in a 5-coordinate geometry to nine O2- atoms. There are a spread of Cs–O bond distances ranging from 3.05–3.57 Å. In the fourth Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to nine O2- atoms. There are a spread of Cs–O bond distances ranging from 3.12–3.43 Å. There are two inequivalent U6+ sites. In the first U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with two equivalent CsO6 octahedra and corners with four SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of U–O bond distances ranging from 1.87–2.26 Å. In the second U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with four SiO4 tetrahedra and edges with two equivalent CsO6 octahedra. There are two shorter (1.86 Å) and four longer (2.27 Å) U–O bond lengths. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one CsO6 octahedra, corners with two UO6 octahedra, and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 35–54°. There are a spread of Si–O bond distances ranging from 1.63–1.66 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one CsO6 octahedra, corners with two UO6 octahedra, and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 19–62°. There are a spread of Si–O bond distances ranging from 1.63–1.67 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two Cs1+, one U6+, and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three Cs1+ and one U6+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one Cs1+, one U6+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to three Cs1+ and one U6+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Cs1+ and two Si4+ atoms. In the sixth O2- site, O2- is bonded in a linear geometry to one Cs1+ and two equivalent Si4+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two Cs1+, one U6+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cs1+ and two equivalent Si4+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to two Cs1+, one U6+, and one Si4+ atom.