Materials Data on Na3Sb3(AsO7)2 by Materials Project
Na3Sb3(AsO7)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 to eight O2- atoms to form NaO8 hexagonal bipyramids that share corners with two equivalent AsO4 tetrahedra and edges with six SbO6 octahedra. There are a spread of Na–O bond distances ranging from 2.53–2.69 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 2.32–2.80 Å. There are two inequivalent Sb5+ sites. In the first Sb5+ site, Sb5+ is bonded to six O2- atoms to form SbO6 octahedra that share corners with four SbO6 octahedra, corners with two equivalent AsO4 tetrahedra, and edges with two equivalent NaO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 41–49°. There are a spread of Sb–O bond distances ranging from 1.97–2.05 Å. In the second Sb5+ site, Sb5+ is bonded to six O2- atoms to form SbO6 octahedra that share corners with four equivalent SbO6 octahedra, corners with two equivalent AsO4 tetrahedra, and edges with two equivalent NaO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 41–49°. There are a spread of Sb–O bond distances ranging from 1.98–2.08 Å. As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share a cornercorner with one NaO8 hexagonal bipyramid and corners with three SbO6 octahedra. The corner-sharing octahedra tilt angles range from 42–58°. There are a spread of As–O bond distances ranging from 1.67–1.76 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+ and two equivalent Sb5+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Sb5+, and one As5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Sb5+, and one As5+ atom. In the fourth O2- site, O2- is bonded to three Na1+ and one As5+ atom to form a mixture of distorted edge and corner-sharing ONa3As tetrahedra. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one Sb5+, and one As5+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+ and two Sb5+ atoms. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and two Sb5+ atoms.