Materials Data on Li2FePO5 by Materials Project
Li2FePO5 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Li1+ is bonded to six O2- atoms to form distorted LiO6 octahedra that share corners with two equivalent LiO6 octahedra, corners with four equivalent PO4 tetrahedra, and edges with four equivalent LiO6 octahedra. The corner-sharing octahedral tilt angles are 37°. There are four shorter (2.12 Å) and two longer (2.39 Å) Li–O bond lengths. Fe3+ is bonded in a 5-coordinate geometry to five O2- atoms. There is one shorter (1.80 Å) and four longer (2.06 Å) Fe–O bond length. P5+ is bonded to four equivalent O2- atoms to form PO4 tetrahedra that share corners with eight equivalent LiO6 octahedra. The corner-sharing octahedral tilt angles are 59°. All P–O bond lengths are 1.55 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Li1+, one Fe3+, and one P5+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to four equivalent Li1+ and one Fe3+ atom.