Materials Data on Sr3W2O9 by Materials Project

Abstract

Sr3W2O9 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to six O2- atoms to form distorted SrO6 octahedra that share corners with two equivalent SrO6 octahedra, corners with four WO4 tetrahedra, edges with two equivalent SrO6 octahedra, and edges with two equivalent SrO5 square pyramids. The corner-sharing octahedral tilt angles are 59°. There are a spread of Sr–O bond distances ranging from 2.35–2.67 Å. In the second Sr2+ site, Sr2+ is bonded to five O2- atoms to form distorted SrO5 square pyramids that share corners with four WO4 tetrahedra and edges with three SrO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.31–2.65 Å. In the third Sr2+ site, Sr2+ is bonded to six O2- atoms to form distorted SrO6 octahedra that share corners with five WO4 tetrahedra, edges with two equivalent SrO6 octahedra, and an edgeedge with one SrO5 square pyramid. There are a spread of Sr–O bond distances ranging from 2.38–2.98 Å. There are two inequivalent W6+ sites. In the first W6+ site, W6+ is bonded to four O2- atoms to form WO4 tetrahedra that share corners with five SrO6 octahedra and corners with two equivalent SrO5 square pyramids. The corner-sharing octahedra tilt angles range from 46–52°. There is one shorter (1.80 Å) and three longer (1.82 Å) W–O bond length. In the second W6+ site, W6+ is bonded to four O2- atoms to form WO4 tetrahedra that share corners with four SrO6 octahedra and corners with two equivalent SrO5 square pyramids. The corner-sharing octahedra tilt angles range from 11–50°. There are a spread of W–O bond distances ranging from 1.80–1.84 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded to four Sr2+ atoms to form corner-sharing OSr4 tetrahedra. In the second O2- site, O2- is bonded in a linear geometry to one Sr2+ and one W6+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two Sr2+ and one W6+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Sr2+ and one W6+ atom. In the fifth O2- site, O2- is bonded in a linear geometry to one Sr2+ and one W6+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one Sr2+ and one W6+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to two Sr2+ and one W6+ atom.