Materials Data on Li2Fe3F8 by Materials Project

Abstract

Li2Fe3F8 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Li1+ is bonded to four F1- atoms to form distorted LiF4 tetrahedra that share corners with five equivalent FeF5 trigonal bipyramids. There are a spread of Li–F bond distances ranging from 1.89–1.95 Å. There are two inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded in a square co-planar geometry to four F1- atoms. There are two shorter (1.99 Å) and two longer (2.02 Å) Fe–F bond lengths. In the second Fe2+ site, Fe2+ is bonded to five F1- atoms to form distorted FeF5 trigonal bipyramids that share corners with five equivalent LiF4 tetrahedra and corners with two equivalent FeF5 trigonal bipyramids. There are a spread of Fe–F bond distances ranging from 1.96–2.15 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a trigonal planar geometry to one Li1+ and two equivalent Fe2+ atoms. In the second F1- site, F1- is bonded in a water-like geometry to one Li1+ and one Fe2+ atom. In the third F1- site, F1- is bonded in a 3-coordinate geometry to one Li1+ and two Fe2+ atoms. In the fourth F1- site, F1- is bonded in a trigonal planar geometry to one Li1+ and two Fe2+ atoms.