Materials Data on CsFeF4 by Materials Project
CsFeF4 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 8-coordinate geometry to eight equivalent F1- atoms. All Cs–F bond lengths are 3.18 Å. In the second Cs1+ site, Cs1+ is bonded in a 12-coordinate geometry to twelve F1- atoms. There are a spread of Cs–F bond distances ranging from 3.05–3.36 Å. Fe3+ is bonded to six F1- atoms to form corner-sharing FeF6 octahedra. The corner-sharing octahedral tilt angles are 18°. There is two shorter (1.90 Å) and four longer (2.01 Å) Fe–F bond length. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted single-bond geometry to four Cs1+ and one Fe3+ atom. In the second F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one Cs1+ and two equivalent Fe3+ atoms.