Materials Data on Na3NbAs2O9 by Materials Project

Abstract

Na3NbO(AsO4)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.30–2.85 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.29–2.93 Å. In the third Na1+ site, Na1+ is bonded in a 4-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.31–2.98 Å. Nb5+ is bonded to six O2- atoms to form distorted NbO6 octahedra that share corners with five AsO4 tetrahedra. There are a spread of Nb–O bond distances ranging from 1.78–2.36 Å. There are two 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 NbO6 octahedra. The corner-sharing octahedra tilt angles range from 23–46°. There are a spread of As–O bond distances ranging from 1.68–1.78 Å. In the second As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with three equivalent NbO6 octahedra. The corner-sharing octahedra tilt angles range from 43–58°. There are a spread of As–O bond distances ranging from 1.69–1.75 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one As5+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, one Nb5+, and one As5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Nb5+, and one As5+ atom. In the fourth O2- site, O2- is bonded in a distorted see-saw-like geometry to three Na1+ and one As5+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one As5+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Nb5+, and one As5+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one Nb5+, and one As5+ atom. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb5+ and one As5+ atom. In the ninth O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+ and one Nb5+ atom.