DOI: 10.17188/1675961
title: Materials Data on KCaCr2F9 by Materials Project

description: KCaCr2F9 crystallizes in the orthorhombic C222_1 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 10-coordinate geometry to ten F1- atoms. There are a spread of K–F bond distances ranging from 2.86–3.18 Å. In the second K1+ site, K1+ is bonded in a 10-coordinate geometry to ten F1- atoms. There are a spread of K–F bond distances ranging from 2.89–3.16 Å. There are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six F1- atoms to form distorted CaF6 octahedra that share corners with six CrF6 octahedra. The corner-sharing octahedra tilt angles range from 20–61°. There are a spread of Ca–F bond distances ranging from 2.19–2.41 Å. In the second Ca2+ site, Ca2+ is bonded to six F1- atoms to form distorted CaF6 octahedra that share corners with six CrF6 octahedra. The corner-sharing octahedra tilt angles range from 29–61°. There are a spread of Ca–F bond distances ranging from 2.24–2.42 Å. There are three inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded to six F1- atoms to form CrF6 octahedra that share corners with three CaF6 octahedra and corners with three CrF6 octahedra. The corner-sharing octahedra tilt angles range from 26–61°. There are a spread of Cr–F bond distances ranging from 1.92–1.99 Å. In the second Cr3+ site, Cr3+ is bonded to six F1- atoms to form CrF6 octahedra that share corners with three equivalent CaF6 octahedra and corners with three CrF6 octahedra. The corner-sharing octahedra tilt angles range from 25–60°. There are a spread of Cr–F bond distances ranging from 1.92–1.99 Å. In the third Cr3+ site, Cr3+ is bonded to six F1- atoms to form CrF6 octahedra that share corners with three CaF6 octahedra and corners with three CrF6 octahedra. The corner-sharing octahedra tilt angles range from 20–61°. There are a spread of Cr–F bond distances ranging from 1.90–1.96 Å. There are fourteen inequivalent F1- sites. In the first F1- site, F1- is bonded in a 1-coordinate geometry to two equivalent K1+, one Ca2+, and one Cr3+ atom. In the second F1- site, F1- is bonded in a 2-coordinate geometry to two K1+, one Ca2+, and one Cr3+ atom. In the third F1- site, F1- is bonded in a bent 150 degrees geometry to two Cr3+ atoms. In the fourth F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one K1+, one Ca2+, and one Cr3+ atom. In the fifth F1- site, F1- is bonded in a bent 150 degrees geometry to one Ca2+ and one Cr3+ atom. In the sixth F1- site, F1- is bonded in a bent 150 degrees geometry to two equivalent Cr3+ atoms. In the seventh F1- site, F1- is bonded in a bent 150 degrees geometry to two equivalent Cr3+ atoms. In the eighth F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one K1+, one Ca2+, and one Cr3+ atom. In the ninth F1- site, F1- is bonded in a 1-coordinate geometry to two K1+, one Ca2+, and one Cr3+ atom. In the tenth F1- site, F1- is bonded in a 2-coordinate geometry to two equivalent K1+, one Ca2+, and one Cr3+ atom. In the eleventh F1- site, F1- is bonded in a 1-coordinate geometry to two K1+, one Ca2+, and one Cr3+ atom. In the twelfth F1- site, F1- is bonded in a bent 150 degrees geometry to two Cr3+ atoms. In the thirteenth F1- site, F1- is bonded in a 2-coordinate geometry to two K1+, one Ca2+, and one Cr3+ atom. In the fourteenth F1- site, F1- is bonded in a bent 150 degrees geometry to one K1+ and two Cr3+ atoms.