DOI: 10.17188/1685065
title: Materials Data on Li3Fe2P2(O4F)2 by Materials Project

description: Li3Fe2P2(O4F)2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two 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 equivalent PO4 tetrahedra, an edgeedge with one LiO4F2 octahedra, edges with two equivalent FeO4F2 octahedra, an edgeedge with one PO4 tetrahedra, and an edgeedge with one LiO4F trigonal bipyramid. The corner-sharing octahedra tilt angles range from 45–58°. There are a spread of Li–O bond distances ranging from 2.00–2.15 Å. The Li–F bond length is 1.92 Å. In the second Li1+ site, Li1+ is bonded to four O2- and two equivalent F1- atoms to form LiO4F2 octahedra that share corners with two equivalent FeO4F2 octahedra, corners with four equivalent PO4 tetrahedra, edges with two equivalent LiO4F trigonal bipyramids, and faces with two equivalent FeO4F2 octahedra. The corner-sharing octahedral tilt angles are 38°. There are two shorter (2.02 Å) and two longer (2.34 Å) Li–O bond lengths. Both Li–F bond lengths are 2.02 Å. There are two inequivalent Fe+2.50+ sites. In the first Fe+2.50+ site, Fe+2.50+ is bonded to four O2- and two equivalent F1- atoms to form FeO4F2 octahedra that share corners with two equivalent LiO4F2 octahedra, corners with two equivalent FeO4F2 octahedra, corners with four equivalent PO4 tetrahedra, and edges with four equivalent LiO4F trigonal bipyramids. The corner-sharing octahedra tilt angles range from 38–55°. There are two shorter (1.96 Å) and two longer (2.07 Å) Fe–O bond lengths. Both Fe–F bond lengths are 2.02 Å. In the second Fe+2.50+ site, Fe+2.50+ is bonded to four O2- and two equivalent F1- atoms to form FeO4F2 octahedra that share corners with two equivalent FeO4F2 octahedra, corners with four equivalent PO4 tetrahedra, corners with four equivalent LiO4F trigonal bipyramids, and faces with two equivalent LiO4F2 octahedra. The corner-sharing octahedral tilt angles are 55°. There are two shorter (2.07 Å) and two longer (2.13 Å) Fe–O bond lengths. Both Fe–F bond lengths are 2.13 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent LiO4F2 octahedra, corners with four FeO4F2 octahedra, corners with two equivalent LiO4F trigonal bipyramids, and an edgeedge with one LiO4F trigonal bipyramid. The corner-sharing octahedra tilt angles range from 26–52°. There are a spread of P–O bond distances ranging from 1.53–1.58 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Li1+, one Fe+2.50+, and one P5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one Fe+2.50+, and one P5+ atom. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Li1+, one Fe+2.50+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted T-shaped geometry to one Li1+, one Fe+2.50+, and one P5+ atom. F1- is bonded in a 4-coordinate geometry to two Li1+ and two Fe+2.50+ atoms.