Materials Data on Li2FeOF3 by Materials Project

Li2FeOF3 is Spinel-derived structured and crystallizes in the tetragonal P4_1 space group. The structure is three-dimensional. there are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to one O2- and three F1- atoms to form LiOF3 tetrahedra that share corners with six equivalent LiOF5 octahedra and corners with six equivalent FeO2F4 octahedra. The corner-sharing octahedra tilt angles range from 54–62°. The Li–O bond length is 1.96 Å. There are a spread of Li–F bond distances ranging from 1.94–2.00 Å. In the second Li1+ site, Li1+ is bonded to one O2- and five F1- atoms to form LiOF5 octahedra that share corners with six equivalent LiOF3 tetrahedra, edges with two equivalent LiOF5 octahedra, and edges with four equivalent FeO2F4 octahedra. The Li–O bond length is 2.09 Å. There are a spread of Li–F bond distances ranging from 2.01–2.12 Å. Fe3+ is bonded to two equivalent O2- and four F1- atoms to form FeO2F4 octahedra that share corners with six equivalent LiOF3 tetrahedra, edges with two equivalent FeO2F4 octahedra, and edges with four equivalent LiOF5 octahedra. There is one shorter (1.90 Å) and one longer (1.92 Å) Fe–O bond length. There are a spread of Fe–F bond distances ranging from 2.00–2.20 Å. O2- is bonded to two Li1+ and two equivalent Fe3+ atoms to form distorted corner-sharing OLi2Fe2 trigonal pyramids. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a rectangular see-saw-like geometry to two Li1+ and two equivalent 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.