Materials Data on KCaF3 by Materials Project

Abstract

KCaF3 is Orthorhombic Perovskite structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. K1+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are a spread of K–F bond distances ranging from 2.70–3.10 Å. Ca2+ is bonded to six F1- atoms to form corner-sharing CaF6 octahedra. The corner-sharing octahedral tilt angles are 27°. There are two shorter (2.27 Å) and four longer (2.28 Å) Ca–F bond lengths. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a 5-coordinate geometry to three equivalent K1+ and two equivalent Ca2+ atoms. In the second F1- site, F1- is bonded to two equivalent K1+ and two equivalent Ca2+ atoms to form distorted corner-sharing FK2Ca2 tetrahedra.