Materials Data on K2FeF5 by Materials Project
K2FeF5 crystallizes in the orthorhombic Pnma 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 2.75–3.11 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 2.65–3.09 Å. Fe3+ is bonded to six F1- atoms to form corner-sharing FeF6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Fe–F bond distances ranging from 1.91–2.06 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a linear geometry to four K1+ and two equivalent Fe3+ atoms. In the second F1- site, F1- is bonded in a 1-coordinate geometry to four K1+ and one Fe3+ atom. In the third F1- site, F1- is bonded in a 5-coordinate geometry to four K1+ and one Fe3+ atom. In the fourth F1- site, F1- is bonded in a distorted single-bond geometry to four K1+ and one Fe3+ atom.