DOI: 10.17188/1269221
title: Materials Data on Na2AlB(As2O7)2 by Materials Project

description: Na2AlB(As2O7)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 4-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.31–2.92 Å. In the second Na1+ site, Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.36–2.96 Å. Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AsO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.87–1.94 Å. B3+ is bonded to four O2- atoms to form BO4 tetrahedra that share corners with four AsO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.47–1.50 Å. There are four inequivalent As5+ sites. In the first As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent AlO6 octahedra and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 48–58°. There are a spread of As–O bond distances ranging from 1.66–1.84 Å. In the second As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent AlO6 octahedra, a cornercorner with one BO4 tetrahedra, and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–56°. There are a spread of As–O bond distances ranging from 1.70–1.77 Å. In the third As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent AlO6 octahedra, a cornercorner with one BO4 tetrahedra, and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–58°. There are a spread of As–O bond distances ranging from 1.70–1.77 Å. In the fourth As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share a cornercorner with one AsO4 tetrahedra and corners with two equivalent BO4 tetrahedra. There are a spread of As–O bond distances ranging from 1.65–1.80 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one B3+, and one As5+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Na1+, one Al3+, and one As5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Al3+, and one As5+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Al3+, and one As5+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Na1+ and one As5+ atom. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to two As5+ atoms. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Al3+, and one As5+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to three equivalent Na1+ and one As5+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Na1+ and two As5+ atoms. In the tenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Na1+, one B3+, and one As5+ atom. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Al3+, and one As5+ atom. In the twelfth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one B3+, and one As5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Al3+, and one As5+ atom. In the fourteenth O2- site, O2- is bonded in a bent 120 degrees geometry to one B3+ and one As5+ atom.