Materials Data on Sr5U5O18 by Materials Project
Sr5U5O18 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to seven O2- atoms to form distorted SrO7 pentagonal bipyramids that share a cornercorner with one UO6 octahedra, a cornercorner with one UO7 pentagonal bipyramid, edges with two equivalent SrO7 pentagonal bipyramids, and edges with two equivalent UO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 56°. There are a spread of Sr–O bond distances ranging from 2.49–2.66 Å. In the second Sr2+ site, Sr2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.55–2.94 Å. In the third Sr2+ site, Sr2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.45–2.90 Å. There are three inequivalent U+5.20+ sites. In the first U+5.20+ site, U+5.20+ is bonded to six O2- atoms to form UO6 octahedra that share corners with two equivalent SrO7 pentagonal bipyramids and corners with two equivalent UO7 pentagonal bipyramids. There are a spread of U–O bond distances ranging from 2.03–2.23 Å. In the second U+5.20+ site, U+5.20+ is bonded to seven O2- atoms to form distorted UO7 pentagonal bipyramids that share a cornercorner with one UO6 octahedra, a cornercorner with one SrO7 pentagonal bipyramid, edges with two equivalent SrO7 pentagonal bipyramids, and edges with two equivalent UO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 38°. There are a spread of U–O bond distances ranging from 2.00–2.63 Å. In the third U+5.20+ site, U+5.20+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of U–O bond distances ranging from 2.01–2.67 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded to three Sr2+ and one U+5.20+ atom to form a mixture of distorted edge and corner-sharing OSr3U tetrahedra. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Sr2+ and three U+5.20+ atoms. In the third O2- site, O2- is bonded to three Sr2+ and one U+5.20+ atom to form a mixture of distorted edge and corner-sharing OSr3U tetrahedra. In the fourth O2- site, O2- is bonded to three Sr2+ and one U+5.20+ atom to form a mixture of distorted edge and corner-sharing OSr3U tetrahedra. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to one Sr2+ and three U+5.20+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Sr2+ and three U+5.20+ atoms. In the seventh O2- site, O2- is bonded to three Sr2+ and one U+5.20+ atom to form a mixture of distorted edge and corner-sharing OSr3U tetrahedra. In the eighth O2- site, O2- is bonded to three Sr2+ and one U+5.20+ atom to form a mixture of distorted edge and corner-sharing OSr3U tetrahedra. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to one Sr2+ and three U+5.20+ atoms.