DOI: 10.17188/1698533
title: Materials Data on SrCr9Ga3O19 by Materials Project

description: SrCr9Ga3O19 is beta indium sulfide-derived structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with six equivalent SrO12 cuboctahedra, edges with six CrO6 octahedra, edges with three equivalent GaO5 trigonal bipyramids, and faces with six CrO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.78–2.96 Å. There are five inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with two equivalent CrO6 octahedra, corners with three GaO4 tetrahedra, a cornercorner with one GaO5 trigonal bipyramid, an edgeedge with one SrO12 cuboctahedra, and edges with five CrO6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are a spread of Cr–O bond distances ranging from 1.94–2.09 Å. In the second Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with two equivalent CrO6 octahedra, corners with three GaO4 tetrahedra, a cornercorner with one GaO5 trigonal bipyramid, an edgeedge with one SrO12 cuboctahedra, and edges with five CrO6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are a spread of Cr–O bond distances ranging from 1.94–2.10 Å. In the third Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six equivalent CrO6 octahedra, corners with three equivalent GaO5 trigonal bipyramids, faces with three equivalent SrO12 cuboctahedra, and a faceface with one CrO6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are three shorter (2.00 Å) and three longer (2.07 Å) Cr–O bond lengths. In the fourth Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six equivalent CrO6 octahedra, corners with three equivalent GaO5 trigonal bipyramids, faces with three equivalent SrO12 cuboctahedra, and a faceface with one CrO6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are three shorter (2.01 Å) and three longer (2.06 Å) Cr–O bond lengths. In the fifth Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six GaO4 tetrahedra and edges with six CrO6 octahedra. There are three shorter (2.01 Å) and three longer (2.02 Å) Cr–O bond lengths. There are three inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four O2- atoms to form GaO4 tetrahedra that share corners with twelve CrO6 octahedra. The corner-sharing octahedra tilt angles range from 54–58°. There is three shorter (1.89 Å) and one longer (1.91 Å) Ga–O bond length. In the second Ga3+ site, Ga3+ is bonded to four O2- atoms to form GaO4 tetrahedra that share corners with twelve CrO6 octahedra. The corner-sharing octahedra tilt angles range from 54–58°. All Ga–O bond lengths are 1.90 Å. In the third Ga3+ site, Ga3+ is bonded to five O2- atoms to form GaO5 trigonal bipyramids that share corners with twelve CrO6 octahedra and edges with three equivalent SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 38–60°. There are a spread of Ga–O bond distances ranging from 1.86–2.37 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Cr3+ and one Ga3+ atom. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Cr3+ and one Ga3+ atom. In the third O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Sr2+, two Cr3+, and one Ga3+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Sr2+ and three Cr3+ atoms. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Sr2+ and three Cr3+ atoms. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to three equivalent Cr3+ and one Ga3+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal pyramidal geometry to three equivalent Cr3+ and one Ga3+ atom. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three equivalent Cr3+ and one Ga3+ atom. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three equivalent Cr3+ and one Ga3+ atom.