DOI: 10.17188/1754379
title: Materials Data on Li2FePO4F by Materials Project

description: Li2FePO4F crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to four O2- and one F1- atom to form distorted LiO4F trigonal bipyramids that share corners with two equivalent FeO4F2 octahedra, corners with two PO4 tetrahedra, an edgeedge with one LiO4F2 octahedra, edges with two equivalent FeO4F2 octahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 42–55°. There are a spread of Li–O bond distances ranging from 1.99–2.27 Å. The Li–F bond length is 1.89 Å. In the second Li1+ site, Li1+ is bonded in a 6-coordinate geometry to five O2- and one F1- atom. There are a spread of Li–O bond distances ranging from 1.96–2.43 Å. The Li–F bond length is 2.33 Å. In the third Li1+ site, Li1+ is bonded to four O2- and two F1- atoms to form distorted LiO4F2 octahedra that share corners with two equivalent FeO4F2 octahedra, corners with four PO4 tetrahedra, an edgeedge with one LiO4F trigonal bipyramid, and faces with two equivalent FeO4F2 octahedra. The corner-sharing octahedra tilt angles range from 35–44°. There are a spread of Li–O bond distances ranging from 2.09–2.37 Å. There is one shorter (1.91 Å) and one longer (2.01 Å) Li–F bond length. In the fourth Li1+ site, Li1+ is bonded in a 5-coordinate geometry to four O2- and one F1- atom. There are a spread of Li–O bond distances ranging from 1.91–2.39 Å. The Li–F bond length is 1.88 Å. There are two inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to four O2- and two F1- atoms to form FeO4F2 octahedra that share corners with two equivalent LiO4F2 octahedra, corners with two equivalent FeO4F2 octahedra, corners with four PO4 tetrahedra, and edges with two equivalent LiO4F trigonal bipyramids. The corner-sharing octahedra tilt angles range from 35–59°. There are a spread of Fe–O bond distances ranging from 2.10–2.18 Å. There are one shorter (2.13 Å) and one longer (2.22 Å) Fe–F bond lengths. In the second Fe2+ site, Fe2+ is bonded to four O2- and two F1- atoms to form FeO4F2 octahedra that share corners with two equivalent FeO4F2 octahedra, corners with four PO4 tetrahedra, corners with two equivalent LiO4F trigonal bipyramids, and faces with two equivalent LiO4F2 octahedra. The corner-sharing octahedral tilt angles are 59°. There are a spread of Fe–O bond distances ranging from 2.06–2.26 Å. There are one shorter (2.10 Å) and one longer (2.19 Å) Fe–F bond lengths. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent LiO4F2 octahedra, corners with four FeO4F2 octahedra, a cornercorner with one LiO4F trigonal bipyramid, and an edgeedge with one LiO4F trigonal bipyramid. The corner-sharing octahedra tilt angles range from 23–55°. There are a spread of P–O bond distances ranging from 1.54–1.58 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent LiO4F2 octahedra, corners with four FeO4F2 octahedra, and a cornercorner with one LiO4F trigonal bipyramid. The corner-sharing octahedra tilt angles range from 25–54°. There is two shorter (1.55 Å) and two longer (1.56 Å) P–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two Li1+, one Fe2+, and one P5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one Fe2+, and one P5+ atom. In the third O2- site, O2- is bonded in a 5-coordinate geometry to three Li1+, one Fe2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Li1+, one Fe2+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a 5-coordinate geometry to three Li1+, one Fe2+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+, one Fe2+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Li1+, one Fe2+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Li1+, one Fe2+, and one P5+ atom. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a 5-coordinate geometry to three Li1+ and two Fe2+ atoms. In the second F1- site, F1- is bonded in a distorted see-saw-like geometry to two Li1+ and two Fe2+ atoms.