Materials Data on Sr3(AlN2)2 by Materials Project
Sr3(AlN2)2 crystallizes in the orthorhombic Pnna space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to six N3- atoms to form distorted SrN6 octahedra that share corners with six equivalent AlN4 tetrahedra, edges with two equivalent SrN6 octahedra, and edges with three equivalent AlN4 tetrahedra. There are a spread of Sr–N bond distances ranging from 2.70–2.96 Å. In the second Sr2+ site, Sr2+ is bonded in a 4-coordinate geometry to four N3- atoms. There are a spread of Sr–N bond distances ranging from 2.52–2.79 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four N3- atoms to form AlN4 tetrahedra that share corners with six equivalent SrN6 octahedra and edges with two equivalent AlN4 tetrahedra. The corner-sharing octahedra tilt angles range from 30–78°. There is two shorter (1.93 Å) and two longer (1.97 Å) Al–N bond length. In the second Al3+ site, Al3+ is bonded to four N3- atoms to form AlN4 tetrahedra that share edges with three equivalent SrN6 octahedra and edges with two equivalent AlN4 tetrahedra. There is two shorter (1.90 Å) and two longer (1.94 Å) Al–N bond length. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a 6-coordinate geometry to four Sr2+ and two Al3+ atoms. In the second N3- site, N3- is bonded in a 5-coordinate geometry to three Sr2+ and two Al3+ atoms.