Materials Data on Li2FeF4 by Materials Project
Li2FeF4 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a 4-coordinate geometry to six F1- atoms. There are a spread of Li–F bond distances ranging from 1.91–2.58 Å. In the second Li1+ site, Li1+ is bonded in a 5-coordinate geometry to five F1- atoms. There are a spread of Li–F bond distances ranging from 1.92–2.35 Å. Fe2+ is bonded to six F1- atoms to form corner-sharing FeF6 octahedra. The corner-sharing octahedra tilt angles range from 47–49°. There are a spread of Fe–F bond distances ranging from 2.02–2.14 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a 5-coordinate geometry to three Li1+ and two equivalent Fe2+ atoms. In the second F1- site, F1- is bonded to three Li1+ and one Fe2+ atom to form a mixture of distorted corner and edge-sharing FLi3Fe trigonal pyramids. In the third F1- site, F1- is bonded to three Li1+ and one Fe2+ atom to form distorted FLi3Fe trigonal pyramids that share corners with eight FLi3Fe trigonal pyramids and edges with two FLi2Fe2 trigonal pyramids. In the fourth F1- site, F1- is bonded to two Li1+ and two equivalent Fe2+ atoms to form a mixture of distorted corner and edge-sharing FLi2Fe2 trigonal pyramids.