Materials Data on Li2FeF4 by Materials Project

Abstract

Li2FeF4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to four F1- atoms to form LiF4 tetrahedra that share corners with two equivalent LiF4 tetrahedra, corners with four equivalent FeF4 tetrahedra, and an edgeedge with one LiF4 tetrahedra. There is one shorter (1.90 Å) and three longer (1.91 Å) Li–F bond length. In the second Li1+ site, Li1+ is bonded to four F1- atoms to form LiF4 tetrahedra that share corners with four LiF4 tetrahedra and corners with four equivalent FeF4 tetrahedra. There are a spread of Li–F bond distances ranging from 1.90–1.92 Å. Fe2+ is bonded to four F1- atoms to form FeF4 tetrahedra that share corners with eight LiF4 tetrahedra. There are a spread of Fe–F bond distances ranging from 1.96–2.02 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted T-shaped geometry to two equivalent Li1+ and one Fe2+ atom. In the second F1- site, F1- is bonded in a trigonal planar geometry to two Li1+ and one Fe2+ atom. In the third F1- site, F1- is bonded in a trigonal planar geometry to two Li1+ and one Fe2+ atom. In the fourth F1- site, F1- is bonded in a trigonal planar geometry to two equivalent Li1+ and one Fe2+ atom.