Materials Data on KCaF3 by Materials Project

Abstract

KCaF3 is Orthorhombic Perovskite structured and crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are a spread of K–F bond distances ranging from 2.67–3.22 Å. In the second K1+ site, K1+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of K–F bond distances ranging from 2.74–3.30 Å. There are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six F1- atoms to form corner-sharing CaF6 octahedra. The corner-sharing octahedra tilt angles range from 24–29°. All Ca–F bond lengths are 2.27 Å. In the second Ca2+ site, Ca2+ is bonded to six F1- atoms to form corner-sharing CaF6 octahedra. The corner-sharing octahedra tilt angles range from 22–29°. There are two shorter (2.26 Å) and four longer (2.27 Å) Ca–F bond lengths. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted see-saw-like geometry to two K1+ and two equivalent Ca2+ atoms. In the second F1- site, F1- is bonded in a 5-coordinate geometry to three K1+ and two equivalent Ca2+ atoms. In the third F1- site, F1- is bonded in a 5-coordinate geometry to three K1+ and two Ca2+ atoms. In the fourth F1- site, F1- is bonded in a 5-coordinate geometry to three K1+ and two Ca2+ atoms.