Materials Data on Na2Nb4O11 by Materials Project

Abstract

Na2Nb4O11 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.44–2.88 Å. In the second Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.50–2.77 Å. There are four inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to seven O2- atoms to form distorted NbO7 pentagonal bipyramids that share corners with two equivalent NbO6 octahedra, a cornercorner with one NbO7 pentagonal bipyramid, and edges with two equivalent NbO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 43–48°. There are a spread of Nb–O bond distances ranging from 1.97–2.48 Å. In the second Nb5+ site, Nb5+ is bonded in a 7-coordinate geometry to six O2- atoms. There are a spread of Nb–O bond distances ranging from 1.97–2.06 Å. In the third Nb5+ site, Nb5+ is bonded to seven O2- atoms to form distorted NbO7 pentagonal bipyramids that share corners with two equivalent NbO6 octahedra, a cornercorner with one NbO7 pentagonal bipyramid, and edges with two equivalent NbO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 46–48°. There are a spread of Nb–O bond distances ranging from 1.89–2.34 Å. In the fourth Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. There are a spread of Nb–O bond distances ranging from 1.90–2.18 Å. There are eleven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and two Nb5+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and two Nb5+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two Nb5+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to three Nb5+ atoms. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+ and three Nb5+ atoms. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+ and three Nb5+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to three Nb5+ atoms. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and two Nb5+ atoms. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and two Nb5+ atoms. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and two Nb5+ atoms. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and two Nb5+ atoms.