Materials Data on LiFe2(P2O7)2 by Materials Project
LiFe2(P2O7)2 crystallizes in the orthorhombic Pccn space group. The structure is three-dimensional. Li is bonded to six O atoms to form LiO6 octahedra that share corners with six PO4 tetrahedra and edges with two equivalent FeO6 octahedra. There are a spread of Li–O bond distances ranging from 2.11–2.18 Å. Fe is bonded to six O atoms to form FeO6 octahedra that share corners with six PO4 tetrahedra, an edgeedge with one LiO6 octahedra, and an edgeedge with one FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.91–2.28 Å. There are two inequivalent P sites. In the first P site, P is bonded to four O atoms to form PO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with three equivalent FeO6 octahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–60°. There are a spread of P–O bond distances ranging from 1.52–1.61 Å. In the second P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two equivalent LiO6 octahedra, corners with three equivalent FeO6 octahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 34–66°. There are a spread of P–O bond distances ranging from 1.50–1.61 Å. There are seven inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to two P atoms. In the second O site, O is bonded in a distorted trigonal planar geometry to two equivalent Fe and one P atom. In the third O site, O is bonded in a bent 150 degrees geometry to one Fe and one P atom. In the fourth O site, O is bonded in a bent 120 degrees geometry to one Li and one P atom. In the fifth O site, O is bonded in a 3-coordinate geometry to one Li, one Fe, and one P atom. In the sixth O site, O is bonded in a bent 150 degrees geometry to one Fe and one P atom. In the seventh O site, O is bonded in a distorted trigonal planar geometry to one Li, one Fe, and one P atom.