DOI: 10.17188/1305082
title: Materials Data on Li2FeF4 by Materials Project

description: Li2FeF4 is Hausmannite-derived structured and crystallizes in the orthorhombic Pnn2 space group. The structure is three-dimensional. there are six inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a 4-coordinate geometry to four F1- atoms. There is two shorter (1.89 Å) and two longer (2.04 Å) Li–F bond length. In the second Li1+ site, Li1+ is bonded in a distorted see-saw-like geometry to four F1- atoms. There is two shorter (1.92 Å) and two longer (1.98 Å) Li–F bond length. In the third Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six F1- atoms. There are a spread of Li–F bond distances ranging from 1.87–2.55 Å. In the fourth Li1+ site, Li1+ is bonded to six F1- atoms to form distorted LiF6 octahedra that share corners with two equivalent FeF6 octahedra, corners with two equivalent LiF4 trigonal pyramids, and edges with six FeF6 octahedra. The corner-sharing octahedral tilt angles are 27°. There are a spread of Li–F bond distances ranging from 1.89–2.42 Å. In the fifth Li1+ site, Li1+ is bonded to four F1- atoms to form LiF4 trigonal pyramids that share a cornercorner with one LiF6 octahedra, corners with three FeF6 octahedra, and an edgeedge with one FeF6 octahedra. The corner-sharing octahedra tilt angles range from 31–68°. There are a spread of Li–F bond distances ranging from 1.86–1.98 Å. In the sixth 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 1.94–2.52 Å. There are three inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to six F1- atoms to form distorted FeF6 octahedra that share corners with two equivalent LiF4 trigonal pyramids, edges with two equivalent LiF6 octahedra, and edges with three FeF6 octahedra. There are a spread of Fe–F bond distances ranging from 2.02–2.24 Å. In the second Fe2+ site, Fe2+ is bonded to six F1- atoms to form FeF6 octahedra that share corners with two equivalent LiF4 trigonal pyramids, edges with two equivalent LiF6 octahedra, and edges with three FeF6 octahedra. There are a spread of Fe–F bond distances ranging from 2.01–2.31 Å. In the third Fe2+ site, Fe2+ is bonded to six F1- atoms to form distorted FeF6 octahedra that share a cornercorner with one LiF6 octahedra, a cornercorner with one LiF4 trigonal pyramid, an edgeedge with one LiF6 octahedra, edges with two FeF6 octahedra, and an edgeedge with one LiF4 trigonal pyramid. The corner-sharing octahedral tilt angles are 27°. There are a spread of Fe–F bond distances ranging from 1.96–2.53 Å. There are eight inequivalent F1- sites. In the first F1- site, F1- is bonded in a 4-coordinate geometry to three Li1+ and one Fe2+ atom. In the second F1- site, F1- is bonded to three Li1+ and one Fe2+ atom to form corner-sharing FLi3Fe tetrahedra. In the third F1- site, F1- is bonded in a 4-coordinate geometry to one Li1+ and three Fe2+ atoms. In the fourth F1- site, F1- is bonded to two Li1+ and two Fe2+ atoms to form distorted corner-sharing FLi2Fe2 tetrahedra. In the fifth F1- site, F1- is bonded in a 4-coordinate geometry to two Li1+ and two Fe2+ atoms. In the sixth F1- site, F1- is bonded in a distorted trigonal planar geometry to two Li1+ and one Fe2+ atom. In the seventh F1- site, F1- is bonded to three Li1+ and one Fe2+ atom to form corner-sharing FLi3Fe tetrahedra. In the eighth F1- site, F1- is bonded in a 4-coordinate geometry to three Li1+ and one Fe2+ atom.