Materials Data on BaAl2Si3(NO)4 by Materials Project

Abstract

BaAl2Si3O4N4 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. Ba2+ is bonded in a 11-coordinate geometry to three N3- and eight O2- atoms. There are two shorter (3.15 Å) and one longer (3.38 Å) Ba–N bond lengths. There are a spread of Ba–O bond distances ranging from 2.87–3.40 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 a cornercorner with one AlN3O tetrahedra and corners with three SiN3O tetrahedra. There are a spread of Al–O bond distances ranging from 1.72–1.79 Å. In the second Al3+ site, Al3+ is bonded to three N3- and one O2- atom to form AlN3O tetrahedra that share a cornercorner with one AlO4 tetrahedra and corners with six SiN3O tetrahedra. There is one shorter (1.85 Å) and two longer (1.86 Å) Al–N bond length. The Al–O bond length is 1.74 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to three N3- and one O2- atom to form SiN3O tetrahedra that share corners with three AlO4 tetrahedra and corners with four equivalent SiN3O tetrahedra. There is two shorter (1.73 Å) and one longer (1.79 Å) Si–N bond length. The Si–O bond length is 1.65 Å. In the second Si4+ site, Si4+ is bonded to three N3- and one O2- atom to form SiN3O tetrahedra that share corners with three AlO4 tetrahedra and corners with four SiN3O tetrahedra. There are a spread of Si–N bond distances ranging from 1.71–1.77 Å. The Si–O bond length is 1.69 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a trigonal planar geometry to one Ba2+ and three Si4+ atoms. In the second N3- site, N3- is bonded in a trigonal planar geometry to one Al3+ and two equivalent Si4+ atoms. In the third N3- site, N3- is bonded in a trigonal planar geometry to one Ba2+, one Al3+, and two Si4+ atoms. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Ba2+, one Al3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Ba2+, one Al3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Ba2+ and two Al3+ atoms.