Materials Data on Sr3(GaAs2)2 by Materials Project

Abstract

Sr3Ga2As4 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to six As3- atoms to form distorted SrAs6 octahedra that share corners with seven SrAs6 octahedra, corners with six equivalent GaAs4 tetrahedra, edges with six equivalent SrAs6 octahedra, edges with three equivalent GaAs4 tetrahedra, and a faceface with one SrAs6 octahedra. The corner-sharing octahedra tilt angles range from 17–60°. There are a spread of Sr–As bond distances ranging from 3.10–3.56 Å. In the second Sr2+ site, Sr2+ is bonded to six As3- atoms to form SrAs6 octahedra that share corners with ten equivalent SrAs6 octahedra, corners with four equivalent GaAs4 tetrahedra, edges with two equivalent SrAs6 octahedra, edges with four equivalent GaAs4 tetrahedra, and faces with two equivalent SrAs6 octahedra. The corner-sharing octahedra tilt angles range from 34–60°. There are a spread of Sr–As bond distances ranging from 3.09–3.26 Å. Ga3+ is bonded to four As3- atoms to form GaAs4 tetrahedra that share corners with eight SrAs6 octahedra, corners with two equivalent GaAs4 tetrahedra, edges with five SrAs6 octahedra, and an edgeedge with one GaAs4 tetrahedra. The corner-sharing octahedra tilt angles range from 22–84°. There are a spread of Ga–As bond distances ranging from 2.50–2.58 Å. There are two inequivalent As3- sites. In the first As3- site, As3- is bonded to five Sr2+ and two equivalent Ga3+ atoms to form distorted AsSr5Ga2 pentagonal bipyramids that share corners with two equivalent AsSr5Ga2 pentagonal bipyramids, corners with four equivalent AsSr4Ga2 pentagonal pyramids, edges with five equivalent AsSr5Ga2 pentagonal bipyramids, edges with six equivalent AsSr4Ga2 pentagonal pyramids, and a faceface with one AsSr5Ga2 pentagonal bipyramid. In the second As3- site, As3- is bonded to four Sr2+ and two equivalent Ga3+ atoms to form distorted AsSr4Ga2 pentagonal pyramids that share corners with four equivalent AsSr5Ga2 pentagonal bipyramids, corners with two equivalent AsSr4Ga2 pentagonal pyramids, edges with six equivalent AsSr5Ga2 pentagonal bipyramids, and edges with four equivalent AsSr4Ga2 pentagonal pyramids.