SrAl4Si2N8O crystallizes in the orthorhombic Imm2 space group. Sr(1) is bonded in a water-like geometry to two equivalent N(2) atoms. Al(1) is bonded to one N(2), one N(3), and two equivalent N(1) atoms to form AlN4 tetrahedra that share corners with three equivalent Si(1)N3O tetrahedra and corners with four equivalent Al(1)N4 tetrahedra. Si(1) is bonded to one N(3), two equivalent N(1), and one O(1) atom to form SiN3O tetrahedra that share  a cornercorner with one Si(1)N3O tetrahedra and corners with six equivalent Al(1)N4 tetrahedra. There are three inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to two equivalent Al(1) and one Si(1) atom. In the second N site, N(2) is bonded in a distorted trigonal planar geometry to one Sr(1) and two equivalent Al(1) atoms. In the third N site, N(3) is bonded in a trigonal planar geometry to two equivalent Al(1) and one Si(1) atom. O(1) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms.
SrAl4Si2N8O crystallizes in the orthorhombic Imm2 space group. Sr(1) is bonded in a water-like geometry to two equivalent N(2) atoms. Both Sr(1)-N(2) bond lengths are 2.54 Å. Al(1) is bonded to one N(2), one N(3), and two equivalent N(1) atoms to form AlN4 tetrahedra that share corners with three equivalent Si(1)N3O tetrahedra and corners with four equivalent Al(1)N4 tetrahedra. The Al(1)-N(2) bond length is 1.87 Å. The Al(1)-N(3) bond length is 1.87 Å. Both Al(1)-N(1) bond lengths are 1.87 Å. Si(1) is bonded to one N(3), two equivalent N(1), and one O(1) atom to form SiN3O tetrahedra that share  a cornercorner with one Si(1)N3O tetrahedra and corners with six equivalent Al(1)N4 tetrahedra. The Si(1)-N(3) bond length is 1.72 Å. Both Si(1)-N(1) bond lengths are 1.73 Å. The Si(1)-O(1) bond length is 1.64 Å. There are three inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to two equivalent Al(1) and one Si(1) atom. In the second N site, N(2) is bonded in a distorted trigonal planar geometry to one Sr(1) and two equivalent Al(1) atoms. In the third N site, N(3) is bonded in a trigonal planar geometry to two equivalent Al(1) and one Si(1) atom. O(1) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms.