Materials Data on KNb3F9 by Materials Project

Abstract

KNb3F9 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. K1+ is bonded in a 6-coordinate geometry to six F1- atoms. There are a spread of K–F bond distances ranging from 3.21–3.26 Å. There are four inequivalent Nb+2.67+ sites. In the first Nb+2.67+ site, Nb+2.67+ is bonded to six F1- atoms to form corner-sharing NbF6 octahedra. The corner-sharing octahedra tilt angles range from 17–46°. There are two shorter (2.12 Å) and four longer (2.16 Å) Nb–F bond lengths. In the second Nb+2.67+ site, Nb+2.67+ is bonded to six F1- atoms to form corner-sharing NbF6 octahedra. The corner-sharing octahedra tilt angles range from 9–45°. There are two shorter (2.10 Å) and four longer (2.15 Å) Nb–F bond lengths. In the third Nb+2.67+ site, Nb+2.67+ is bonded to six F1- atoms to form corner-sharing NbF6 octahedra. The corner-sharing octahedra tilt angles range from 9–45°. There are two shorter (2.10 Å) and four longer (2.15 Å) Nb–F bond lengths. In the fourth Nb+2.67+ site, Nb+2.67+ is bonded to six F1- atoms to form corner-sharing NbF6 octahedra. The corner-sharing octahedra tilt angles range from 17–46°. There are a spread of Nb–F bond distances ranging from 2.12–2.16 Å. There are nine inequivalent F1- sites. In the first F1- site, F1- is bonded in a linear geometry to two Nb+2.67+ atoms. In the second F1- site, F1- is bonded in a linear geometry to two Nb+2.67+ atoms. In the third F1- site, F1- is bonded in a 2-coordinate geometry to one K1+ and two Nb+2.67+ atoms. In the fourth F1- site, F1- is bonded in a 2-coordinate geometry to one K1+ and two Nb+2.67+ atoms. In the fifth F1- site, F1- is bonded in a 2-coordinate geometry to one K1+ and two equivalent Nb+2.67+ atoms. In the sixth F1- site, F1- is bonded in a linear geometry to two Nb+2.67+ atoms. In the seventh F1- site, F1- is bonded in a 2-coordinate geometry to one K1+ and two equivalent Nb+2.67+ atoms. In the eighth F1- site, F1- is bonded in a 2-coordinate geometry to one K1+ and two Nb+2.67+ atoms. In the ninth F1- site, F1- is bonded in a 2-coordinate geometry to one K1+ and two Nb+2.67+ atoms.