Materials Data on Sr3Al2O6 by Materials Project
Sr3Al2O6 crystallizes in the cubic Pa-3 space group. The structure is three-dimensional. there are six inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to six equivalent O2- atoms to form distorted SrO6 octahedra that share corners with six equivalent AlO4 tetrahedra. All Sr–O bond lengths are 2.49 Å. In the second Sr2+ site, Sr2+ is bonded to six equivalent O2- atoms to form SrO6 octahedra that share corners with six equivalent AlO4 tetrahedra and edges with six equivalent SrO8 hexagonal bipyramids. All Sr–O bond lengths are 2.51 Å. In the third Sr2+ site, Sr2+ is bonded to six O2- atoms to form SrO6 octahedra that share corners with six equivalent AlO4 tetrahedra and faces with three equivalent SrO8 hexagonal bipyramids. There are three shorter (2.48 Å) and three longer (2.51 Å) Sr–O bond lengths. In the fourth Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.72–2.97 Å. In the fifth Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Sr–O bond distances ranging from 2.45–2.92 Å. In the sixth Sr2+ site, Sr2+ is bonded to eight O2- atoms to form distorted SrO8 hexagonal bipyramids that share corners with two equivalent SrO8 hexagonal bipyramids, a cornercorner with one AlO4 tetrahedra, edges with two equivalent SrO8 hexagonal bipyramids, an edgeedge with one SrO6 octahedra, edges with five AlO4 tetrahedra, and a faceface with one SrO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.44–2.94 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with two equivalent SrO6 octahedra, corners with two equivalent AlO4 tetrahedra, and edges with three equivalent SrO8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 40°. There are a spread of Al–O bond distances ranging from 1.76–1.79 Å. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share a cornercorner with one SrO8 hexagonal bipyramid, corners with two SrO6 octahedra, corners with two equivalent AlO4 tetrahedra, and edges with two equivalent SrO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 36–43°. There are a spread of Al–O bond distances ranging from 1.76–1.79 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to four Sr2+ and one Al3+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to four Sr2+ and one Al3+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to three Sr2+ and two Al3+ atoms. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to four Sr2+ and one Al3+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to three Sr2+ and two Al3+ atoms. In the sixth O2- site, O2- is bonded in a 5-coordinate geometry to four Sr2+ and one Al3+ atom.