Materials Data on CsFeCuF6 by Materials Project
CsFeCuF6 crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. Cs1+ is bonded to six F1- atoms to form CsF6 octahedra that share corners with six equivalent FeF6 octahedra and corners with six equivalent CuF6 octahedra. The corner-sharing octahedra tilt angles range from 68–70°. There are a spread of Cs–F bond distances ranging from 3.19–3.32 Å. Fe3+ is bonded to six F1- atoms to form FeF6 octahedra that share corners with two equivalent FeF6 octahedra, corners with four equivalent CuF6 octahedra, and corners with six equivalent CsF6 octahedra. The corner-sharing octahedra tilt angles range from 40–70°. There is four shorter (1.94 Å) and two longer (2.01 Å) Fe–F bond length. Cu2+ is bonded to six F1- atoms to form CuF6 octahedra that share corners with two equivalent CuF6 octahedra, corners with four equivalent FeF6 octahedra, and corners with six equivalent CsF6 octahedra. The corner-sharing octahedra tilt angles range from 43–69°. There are two shorter (1.96 Å) and four longer (2.08 Å) Cu–F bond lengths. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one Cs1+ and two equivalent Fe3+ atoms. In the second F1- site, F1- is bonded in a 2-coordinate geometry to one Cs1+ and two equivalent Cu2+ atoms. In the third F1- site, F1- is bonded in a 2-coordinate geometry to one Cs1+, one Fe3+, and one Cu2+ atom.