Materials Data on NaFePO4 by Materials Project

Abstract

NaFePO4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six equivalent FeO4 tetrahedra, corners with six equivalent PO4 tetrahedra, and edges with two equivalent NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.30–2.61 Å. Fe2+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with six equivalent NaO6 octahedra and corners with four equivalent PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 70–79°. There are a spread of Fe–O bond distances ranging from 2.05–2.11 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with six equivalent NaO6 octahedra and corners with four equivalent FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–60°. There are a spread of P–O bond distances ranging from 1.55–1.58 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Fe2+, and one P5+ atom. In the second O2- site, O2- is bonded to two equivalent Na1+, one Fe2+, and one P5+ atom to form distorted corner-sharing ONa2FeP tetrahedra. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+, one Fe2+, and one P5+ atom.