Materials Data on Sr2Sb2O7 by Materials Project

Abstract

Sr2Sb2O7 crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are four shorter (2.53 Å) and four longer (2.86 Å) Sr–O bond lengths. In the second Sr2+ site, Sr2+ is bonded to eight O2- atoms to form distorted SrO8 hexagonal bipyramids that share corners with two equivalent SrO8 hexagonal bipyramids, corners with two equivalent SbO6 octahedra, and edges with six SbO6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are a spread of Sr–O bond distances ranging from 2.40–2.89 Å. There are two inequivalent Sb5+ sites. In the first Sb5+ site, Sb5+ is bonded to six O2- atoms to form SbO6 octahedra that share corners with six SbO6 octahedra and edges with four equivalent SrO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 43–44°. There are four shorter (2.01 Å) and two longer (2.04 Å) Sb–O bond lengths. In the second Sb5+ site, Sb5+ is bonded to six O2- atoms to form SbO6 octahedra that share corners with two equivalent SrO8 hexagonal bipyramids, corners with four equivalent SbO6 octahedra, and edges with two equivalent SrO8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. There are two shorter (1.96 Å) and four longer (2.06 Å) Sb–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two Sr2+ and two Sb5+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Sr2+ and two equivalent Sb5+ atoms. In the third O2- site, O2- is bonded to three Sr2+ and one Sb5+ atom to form a mixture of distorted corner and edge-sharing OSr3Sb tetrahedra.