Materials Data on NaMg3Al6Si6B3O31 by Materials Project

Abstract

NaMg3Al6B3Si6O31 crystallizes in the trigonal R3m space group. The structure is three-dimensional. Na is bonded in a 9-coordinate geometry to nine O atoms. There are a spread of Na–O bond distances ranging from 2.43–2.90 Å. Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent SiO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with two equivalent AlO6 octahedra. There are three shorter (2.05 Å) and three longer (2.10 Å) Mg–O bond lengths. Al is bonded to six O atoms to form AlO6 octahedra that share a cornercorner with one AlO6 octahedra, corners with three equivalent SiO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with two equivalent AlO6 octahedra. The corner-sharing octahedral tilt angles are 40°. There are a spread of Al–O bond distances ranging from 1.88–1.98 Å. B is bonded in a trigonal planar geometry to three O atoms. There is one shorter (1.37 Å) and two longer (1.40 Å) B–O bond length. Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one MgO6 octahedra, corners with three equivalent AlO6 octahedra, and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 48–58°. There are a spread of Si–O bond distances ranging from 1.62–1.65 Å. There are eight inequivalent O sites. In the first O site, O is bonded in a bent 150 degrees geometry to one Na and two equivalent Si atoms. In the second O site, O is bonded in a 2-coordinate geometry to one Na and two equivalent Si atoms. In the third O site, O is bonded in a distorted trigonal planar geometry to one Mg, one Al, and one Si atom. In the fourth O site, O is bonded in a distorted trigonal planar geometry to two equivalent Al and one Si atom. In the fifth O site, O is bonded in a distorted trigonal planar geometry to two equivalent Al and one B atom. In the sixth O site, O is bonded in a distorted T-shaped geometry to three equivalent Mg atoms. In the seventh O site, O is bonded in a 4-coordinate geometry to one Na, two equivalent Mg, and one B atom. In the eighth O site, O is bonded in a T-shaped geometry to one Mg and two equivalent Al atoms.