Materials Data on NaAl6Fe3Si6B3O31 by Materials Project
NaFe3Al6B3Si6O31 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 2.58–2.79 Å. Fe is bonded to six O atoms to form FeO6 octahedra that share corners with two equivalent SiO4 tetrahedra, edges with two equivalent FeO6 octahedra, and edges with two equivalent AlO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.97–2.06 Å. 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 FeO6 octahedra, and edges with two equivalent AlO6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are a spread of Al–O bond distances ranging from 1.90–2.02 Å. B is bonded in a trigonal planar geometry to three O atoms. There is two shorter (1.38 Å) and one longer (1.39 Å) B–O bond length. Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one FeO6 octahedra, corners with three equivalent AlO6 octahedra, and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–57°. There are a spread of Si–O bond distances ranging from 1.62–1.64 Å. There are eight inequivalent O sites. In the first O site, O is bonded in a distorted 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 Fe, 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 trigonal non-coplanar geometry to three equivalent Fe atoms. In the seventh O site, O is bonded in a 1-coordinate geometry to one Na, two equivalent Fe, and one B atom. In the eighth O site, O is bonded in a distorted T-shaped geometry to one Fe and two equivalent Al atoms.