Materials Data on Na2SnBAsO7 by Materials Project
Na2BSnAsO7 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.18–2.77 Å. B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.32–1.45 Å. Sn4+ is bonded to six O2- atoms to form SnO6 octahedra that share corners with four equivalent AsO4 tetrahedra. There are a spread of Sn–O bond distances ranging from 2.06–2.13 Å. As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with four equivalent SnO6 octahedra. The corner-sharing octahedra tilt angles range from 42–51°. There are a spread of As–O bond distances ranging from 1.71–1.75 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Na1+ and one B3+ atom. In the second O2- site, O2- is bonded in a distorted trigonal pyramidal geometry to two equivalent Na1+, one B3+, and one Sn4+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+, one B3+, and one Sn4+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one Sn4+, and one As5+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Na1+, one Sn4+, and one As5+ atom. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to one Sn4+ and one As5+ atom.