Materials Data on Na2NbO4F5 by Materials Project
Na2NbO4F5 crystallizes in the orthorhombic Aea2 space group. The structure is three-dimensional. Na is bonded to three O and three F atoms to form NaO3F3 octahedra that share corners with three equivalent NaO3F3 octahedra and corners with four equivalent NbO2F5 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 53–71°. There are a spread of Na–O bond distances ranging from 2.39–2.49 Å. There are a spread of Na–F bond distances ranging from 2.29–2.42 Å. Nb is bonded to two equivalent O and five F atoms to form distorted NbO2F5 pentagonal bipyramids that share corners with eight equivalent NaO3F3 octahedra. The corner-sharing octahedra tilt angles range from 30–54°. Both Nb–O bond lengths are 2.08 Å. There are a spread of Nb–F bond distances ranging from 1.94–2.01 Å. There are two inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to two equivalent Na atoms. In the second O site, O is bonded in a distorted trigonal non-coplanar geometry to one Na, one Nb, and one O atom. The O–O bond length is 1.39 Å. There are three inequivalent F sites. In the first F site, F is bonded in a bent 150 degrees geometry to one Na and one Nb atom. In the second F site, F is bonded in a trigonal planar geometry to two equivalent Na and one Nb atom. In the third F site, F is bonded in a bent 150 degrees geometry to one Na and one Nb atom.