Materials Data on KNaNbOF5 by Materials Project

Abstract

KNaNbOF5 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. K1+ is bonded in a 8-coordinate geometry to one O2- and seven F1- atoms. The K–O bond length is 2.91 Å. There are a spread of K–F bond distances ranging from 2.72–2.94 Å. Na1+ is bonded to one O2- and five F1- atoms to form NaOF5 octahedra that share corners with four equivalent NbOF5 octahedra and an edgeedge with one NbOF5 octahedra. The corner-sharing octahedra tilt angles range from 25–41°. The Na–O bond length is 2.37 Å. There are a spread of Na–F bond distances ranging from 2.25–2.48 Å. Nb5+ is bonded to one O2- and five F1- atoms to form NbOF5 octahedra that share corners with four equivalent NaOF5 octahedra and an edgeedge with one NaOF5 octahedra. The corner-sharing octahedra tilt angles range from 25–41°. The Nb–O bond length is 1.78 Å. There are a spread of Nb–F bond distances ranging from 1.98–2.16 Å. O2- is bonded in a 1-coordinate geometry to one K1+, one Na1+, and one Nb5+ atom. There are five inequivalent F1- sites. In the first F1- site, F1- is bonded in a 2-coordinate geometry to one K1+, one Na1+, and one Nb5+ atom. In the second F1- site, F1- is bonded to two equivalent K1+, one Na1+, and one Nb5+ atom to form distorted corner-sharing FK2NaNb tetrahedra. In the third F1- site, F1- is bonded in a 2-coordinate geometry to one K1+, one Na1+, and one Nb5+ atom. In the fourth F1- site, F1- is bonded in a 4-coordinate geometry to two equivalent K1+, one Na1+, and one Nb5+ atom. In the fifth F1- site, F1- is bonded in a 2-coordinate geometry to one K1+, one Na1+, and one Nb5+ atom.