DOI: 10.17188/1306867
title: Materials Data on Li9Fe3(OF7)2 by Materials Project

description: Li9Fe3(OF7)2 is Spinel-derived structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are six inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to six F1- atoms to form LiF6 octahedra that share corners with six LiOF3 tetrahedra, edges with three LiO2F4 octahedra, and edges with three FeO2F4 octahedra. There are a spread of Li–F bond distances ranging from 1.93–2.15 Å. In the second Li1+ site, Li1+ is bonded to two equivalent O2- and four F1- atoms to form LiO2F4 octahedra that share corners with six LiOF3 tetrahedra, edges with two equivalent LiF6 octahedra, and edges with four FeO2F4 octahedra. Both Li–O bond lengths are 2.12 Å. There are two shorter (2.05 Å) and two longer (2.08 Å) Li–F bond lengths. In the third Li1+ site, Li1+ is bonded to one O2- and three F1- atoms to form LiOF3 tetrahedra that share corners with four FeO2F4 octahedra and corners with eight LiF6 octahedra. The corner-sharing octahedra tilt angles range from 55–64°. The Li–O bond length is 2.01 Å. There are a spread of Li–F bond distances ranging from 1.92–2.02 Å. In the fourth Li1+ site, Li1+ is bonded to four F1- atoms to form LiF4 tetrahedra that share corners with five FeO2F4 octahedra and corners with seven LiF6 octahedra. The corner-sharing octahedra tilt angles range from 54–63°. There are a spread of Li–F bond distances ranging from 1.91–1.96 Å. In the fifth Li1+ site, Li1+ is bonded to six F1- atoms to form LiF6 octahedra that share corners with six LiOF3 tetrahedra, edges with two equivalent FeF6 octahedra, and edges with four LiF6 octahedra. There are a spread of Li–F bond distances ranging from 2.00–2.11 Å. In the sixth Li1+ site, Li1+ is bonded to six F1- atoms to form LiF6 octahedra that share corners with six LiOF3 tetrahedra, edges with two equivalent FeF6 octahedra, and edges with four LiF6 octahedra. There are a spread of Li–F bond distances ranging from 2.01–2.10 Å. There are three inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to two equivalent O2- and four F1- atoms to form FeO2F4 octahedra that share corners with six LiOF3 tetrahedra, edges with two equivalent FeO2F4 octahedra, and edges with four LiF6 octahedra. Both Fe–O bond lengths are 1.92 Å. There are two shorter (2.03 Å) and two longer (2.11 Å) Fe–F bond lengths. In the second Fe3+ site, Fe3+ is bonded to two equivalent O2- and four F1- atoms to form FeO2F4 octahedra that share corners with six LiOF3 tetrahedra, edges with two equivalent FeO2F4 octahedra, and edges with four LiF6 octahedra. Both Fe–O bond lengths are 1.92 Å. There are two shorter (2.04 Å) and two longer (2.10 Å) Fe–F bond lengths. In the third Fe3+ site, Fe3+ is bonded to six F1- atoms to form FeF6 octahedra that share corners with six LiOF3 tetrahedra and edges with six LiF6 octahedra. There is four shorter (1.96 Å) and two longer (1.97 Å) Fe–F bond length. O2- is bonded to two Li1+ and two Fe3+ atoms to form distorted corner-sharing OLi2Fe2 trigonal pyramids. There are seven inequivalent F1- sites. In the first F1- site, F1- is bonded in a rectangular see-saw-like geometry to two Li1+ and two Fe3+ atoms. In the second F1- site, F1- is bonded in a distorted rectangular see-saw-like geometry to three Li1+ and one Fe3+ atom. In the third F1- site, F1- is bonded in a distorted rectangular see-saw-like geometry to three Li1+ and one Fe3+ atom. In the fourth F1- site, F1- is bonded in a rectangular see-saw-like geometry to three Li1+ and one Fe3+ atom. In the fifth F1- site, F1- is bonded in a rectangular see-saw-like geometry to three Li1+ and one Fe3+ atom. In the sixth F1- site, F1- is bonded in a rectangular see-saw-like geometry to three Li1+ and one Fe3+ atom. In the seventh F1- site, F1- is bonded in a rectangular see-saw-like geometry to four Li1+ atoms.