DOI: 10.17188/1718359
title: Materials Data on Li3Fe2(OF)3 by Materials Project

description: Li3Fe2(OF)3 is Aluminum carbonitride-derived structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are three inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to one O2- and four F1- atoms to form distorted LiOF4 tetrahedra that share corners with nine LiOF4 tetrahedra and edges with three equivalent FeO4F trigonal bipyramids. The Li–O bond length is 2.41 Å. There is one shorter (1.91 Å) and three longer (1.93 Å) Li–F bond length. In the second Li1+ site, Li1+ is bonded to one O2- and three equivalent F1- atoms to form LiOF3 tetrahedra that share corners with three equivalent FeO6 octahedra and corners with nine LiOF3 tetrahedra. The corner-sharing octahedra tilt angles range from 65–66°. The Li–O bond length is 2.00 Å. There is one shorter (1.95 Å) and two longer (1.96 Å) Li–F bond length. In the third Li1+ site, Li1+ is bonded to four F1- atoms to form corner-sharing LiF4 tetrahedra. There is one shorter (1.93 Å) and three longer (1.95 Å) Li–F bond length. There are two inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent LiOF3 tetrahedra, corners with three equivalent FeO4F trigonal bipyramids, and edges with six equivalent FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.05–2.19 Å. In the second Fe3+ site, Fe3+ is bonded to four O2- and one F1- atom to form FeO4F trigonal bipyramids that share corners with three equivalent FeO6 octahedra, corners with six equivalent FeO4F trigonal bipyramids, and edges with three equivalent LiOF4 tetrahedra. The corner-sharing octahedra tilt angles range from 58–59°. There is three shorter (1.89 Å) and one longer (1.92 Å) Fe–O bond length. The Fe–F bond length is 2.24 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to one Li1+ and three equivalent Fe3+ atoms. In the second O2- site, O2- is bonded to one Li1+ and three equivalent Fe3+ atoms to form OLiFe3 tetrahedra that share corners with three equivalent FLi4 tetrahedra, corners with six equivalent OLiFe3 tetrahedra, corners with three equivalent OFe4 trigonal pyramids, and edges with three equivalent OFe4 trigonal pyramids. In the third O2- site, O2- is bonded to four Fe3+ atoms to form distorted OFe4 trigonal pyramids that share a cornercorner with one FLi3Fe tetrahedra, corners with three equivalent OLiFe3 tetrahedra, corners with six equivalent OFe4 trigonal pyramids, and edges with three equivalent OLiFe3 tetrahedra. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded to four Li1+ atoms to form corner-sharing FLi4 tetrahedra. In the second F1- site, F1- is bonded to three equivalent Li1+ and one Fe3+ atom to form distorted FLi3Fe tetrahedra that share corners with nine FLi4 tetrahedra and a cornercorner with one OFe4 trigonal pyramid. In the third F1- site, F1- is bonded to four Li1+ atoms to form FLi4 tetrahedra that share corners with three equivalent OLiFe3 tetrahedra and corners with nine FLi4 tetrahedra.