Materials Data on CaCrF5 by Materials Project

Abstract

CaCrF5 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ca2+ is bonded to seven F1- atoms to form CaF7 pentagonal bipyramids that share corners with four equivalent CrF6 octahedra, edges with two equivalent CrF6 octahedra, and edges with two equivalent CaF7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 2–38°. There are a spread of Ca–F bond distances ranging from 2.22–2.51 Å. Cr3+ is bonded to six F1- atoms to form CrF6 octahedra that share corners with two equivalent CrF6 octahedra, corners with four equivalent CaF7 pentagonal bipyramids, and edges with two equivalent CaF7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 30°. There are a spread of Cr–F bond distances ranging from 1.91–1.98 Å. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a linear geometry to one Ca2+ and one Cr3+ atom. In the second F1- site, F1- is bonded in a 2-coordinate geometry to one Ca2+ and two equivalent Cr3+ atoms. In the third F1- site, F1- is bonded in a 3-coordinate geometry to two equivalent Ca2+ and one Cr3+ atom.