Materials Data on SrAl4Si2N8O by Materials Project
SrAl4Si2N8O crystallizes in the orthorhombic Imm2 space group. The structure is three-dimensional. Sr2+ is bonded in a water-like geometry to two equivalent N+2.50- atoms. Both Sr–N bond lengths are 2.54 Å. Al3+ is bonded to four N+2.50- atoms to form AlN4 tetrahedra that share corners with three equivalent SiN3O tetrahedra and corners with four equivalent AlN4 tetrahedra. All Al–N bond lengths are 1.87 Å. Si4+ is bonded to three N+2.50- and one O2- atom to form SiN3O tetrahedra that share a cornercorner with one SiN3O tetrahedra and corners with six equivalent AlN4 tetrahedra. There is one shorter (1.72 Å) and two longer (1.73 Å) Si–N bond length. The Si–O bond length is 1.64 Å. There are three inequivalent N+2.50- sites. In the first N+2.50- site, N+2.50- is bonded in a trigonal planar geometry to two equivalent Al3+ and one Si4+ atom. In the second N+2.50- site, N+2.50- is bonded in a distorted trigonal planar geometry to one Sr2+ and two equivalent Al3+ atoms. In the third N+2.50- site, N+2.50- is bonded in a trigonal planar geometry to two equivalent Al3+ and one Si4+ atom. O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms.