Materials Data on NaNb6O16 by Materials Project
NaNb6O16 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Na is bonded in a 9-coordinate geometry to nine O atoms. There are a spread of Na–O bond distances ranging from 2.60–2.83 Å. There are four inequivalent Nb sites. In the first Nb site, Nb is bonded to seven O atoms to form NbO7 pentagonal bipyramids that share corners with two equivalent NbO7 pentagonal bipyramids and edges with five NbO6 octahedra. There are a spread of Nb–O bond distances ranging from 1.97–2.15 Å. In the second Nb site, Nb is bonded to six O atoms to form NbO6 octahedra that share corners with six NbO6 octahedra and an edgeedge with one NbO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 11–46°. There are a spread of Nb–O bond distances ranging from 1.97–2.04 Å. In the third Nb site, Nb is bonded to six O atoms to form distorted NbO6 octahedra that share corners with six NbO6 octahedra and an edgeedge with one NbO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 14–39°. There are a spread of Nb–O bond distances ranging from 1.89–2.21 Å. In the fourth Nb site, Nb is bonded to six O atoms to form NbO6 octahedra that share corners with six NbO6 octahedra and an edgeedge with one NbO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 6–46°. There are a spread of Nb–O bond distances ranging from 1.91–2.11 Å. There are ten inequivalent O sites. In the first O site, O is bonded in a linear geometry to two equivalent Nb atoms. In the second O site, O is bonded in a distorted T-shaped geometry to one Na and two equivalent Nb atoms. In the third O site, O is bonded in a distorted T-shaped geometry to one Na and two equivalent Nb atoms. In the fourth O site, O is bonded in a linear geometry to two equivalent Nb atoms. In the fifth O site, O is bonded in a distorted trigonal non-coplanar geometry to three Nb atoms. In the sixth O site, O is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na and two Nb atoms. In the seventh O site, O is bonded in a distorted trigonal planar geometry to three Nb atoms. In the eighth O site, O is bonded in a bent 150 degrees geometry to two Nb atoms. In the ninth O site, O is bonded in a distorted trigonal planar geometry to three Nb atoms. In the tenth O site, O is bonded to two equivalent Na and two equivalent Nb atoms to form distorted corner-sharing ONa2Nb2 tetrahedra.