Materials Data on NaCrF6 by Materials Project

Abstract

NaCrF6 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Na1+ is bonded to seven F1- atoms to form distorted NaF7 pentagonal bipyramids that share corners with five equivalent CrF6 octahedra, an edgeedge with one CrF6 octahedra, and edges with two equivalent NaF7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 20–39°. There are a spread of Na–F bond distances ranging from 2.34–2.55 Å. Cr5+ is bonded to six F1- atoms to form CrF6 octahedra that share corners with five equivalent NaF7 pentagonal bipyramids and an edgeedge with one NaF7 pentagonal bipyramid. There are a spread of Cr–F bond distances ranging from 1.75–1.84 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a 3-coordinate geometry to two equivalent Na1+ and one Cr5+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one Cr5+ atom. In the third F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one Cr5+ atom. In the fourth F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one Cr5+ atom.