DOI: 10.17188/1263239
title: Materials Data on Sr4U2O9 by Materials Project

description: Sr4U2O9 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are nine inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to six O2- atoms to form SrO6 octahedra that share corners with six UO6 octahedra. The corner-sharing octahedra tilt angles range from 32–43°. There are a spread of Sr–O bond distances ranging from 2.44–2.52 Å. In the second Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.48–3.18 Å. In the third Sr2+ site, Sr2+ is bonded in a 4-coordinate geometry to seven O2- atoms. There are a spread of Sr–O bond distances ranging from 2.45–3.09 Å. In the fourth Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Sr–O bond distances ranging from 2.51–2.96 Å. In the fifth Sr2+ site, Sr2+ is bonded in a 5-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.54–3.25 Å. In the sixth Sr2+ site, Sr2+ is bonded to six O2- atoms to form SrO6 octahedra that share corners with six UO6 octahedra. The corner-sharing octahedra tilt angles range from 33–41°. There are a spread of Sr–O bond distances ranging from 2.48–2.52 Å. In the seventh Sr2+ site, Sr2+ is bonded to six O2- atoms to form SrO6 octahedra that share corners with six UO6 octahedra. The corner-sharing octahedra tilt angles range from 34–40°. There are a spread of Sr–O bond distances ranging from 2.46–2.50 Å. In the eighth Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.44–3.12 Å. In the ninth Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.47–3.17 Å. There are five inequivalent U5+ sites. In the first U5+ site, U5+ is bonded to six O2- atoms to form UO6 octahedra that share corners with three SrO6 octahedra and corners with three equivalent UO6 octahedra. The corner-sharing octahedra tilt angles range from 31–37°. There are a spread of U–O bond distances ranging from 2.06–2.33 Å. In the second U5+ site, U5+ is bonded to six O2- atoms to form corner-sharing UO6 octahedra. The corner-sharing octahedra tilt angles range from 31–37°. There are a spread of U–O bond distances ranging from 2.16–2.24 Å. In the third U5+ site, U5+ is bonded to six O2- atoms to form UO6 octahedra that share a cornercorner with one UO6 octahedra and corners with five SrO6 octahedra. The corner-sharing octahedra tilt angles range from 32–41°. There are a spread of U–O bond distances ranging from 2.09–2.38 Å. In the fourth U5+ site, U5+ is bonded to six O2- atoms to form UO6 octahedra that share corners with two equivalent UO6 octahedra and corners with four SrO6 octahedra. The corner-sharing octahedra tilt angles range from 33–43°. There are four shorter (2.11 Å) and two longer (2.33 Å) U–O bond lengths. In the fifth U5+ site, U5+ is bonded to six O2- atoms to form UO6 octahedra that share corners with two equivalent UO6 octahedra and corners with four SrO6 octahedra. The corner-sharing octahedra tilt angles range from 34–36°. There are a spread of U–O bond distances ranging from 2.09–2.36 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to four Sr2+ and one U5+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Sr2+ and two U5+ atoms. In the third O2- site, O2- is bonded in a 5-coordinate geometry to four Sr2+ and one U5+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Sr2+ and two U5+ atoms. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two Sr2+ and two U5+ atoms. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to three Sr2+ and one U5+ atom. In the seventh O2- site, O2- is bonded in a distorted see-saw-like geometry to three Sr2+ and one U5+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to three Sr2+ and one U5+ atom. In the ninth O2- site, O2- is bonded in a 5-coordinate geometry to four Sr2+ and one U5+ atom. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to four Sr2+ and one U5+ atom. In the eleventh O2- site, O2- is bonded in a 5-coordinate geometry to four Sr2+ and one U5+ atom. In the twelfth O2- site, O2- is bonded to three Sr2+ and one U5+ atom to form distorted corner-sharing OSr3U tetrahedra. In the thirteenth O2- site, O2- is bonded in a 5-coordinate geometry to four Sr2+ and one U5+ atom. In the fourteenth O2- site, O2- is bonded to two Sr2+ and two U5+ atoms to form distorted corner-sharing OSr2U2 tetrahedra. In the fifteenth O2- site, O2- is bonded in a 4-coordinate geometry to four Sr2+ and one U5+ atom. In the sixteenth O2- site, O2- is bonded in a 5-coordinate geometry to three Sr2+ and two U5+ atoms. In the seventeenth O2- site, O2- is bonded in a 4-coordinate geometry to three Sr2+ and two U5+ atoms. In the eighteenth O2- site, O2- is bonded in a 4-coordinate geometry to three Sr2+ and one U5+ atom.