DOI: 10.17188/1700061
title: Materials Data on Fe9PO12 by Materials Project

description: Fe9PO12 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are seven inequivalent Fe+2.11+ sites. In the first Fe+2.11+ site, Fe+2.11+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are a spread of Fe–O bond distances ranging from 2.14–2.72 Å. In the second Fe+2.11+ site, Fe+2.11+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one FeO6 octahedra, corners with two equivalent PO4 tetrahedra, corners with four equivalent FeO4 tetrahedra, and edges with six FeO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Fe–O bond distances ranging from 2.11–2.51 Å. In the third Fe+2.11+ site, Fe+2.11+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one FeO6 octahedra, corners with two equivalent FeO4 tetrahedra, corners with four equivalent PO4 tetrahedra, and edges with six FeO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Fe–O bond distances ranging from 1.99–2.31 Å. In the fourth Fe+2.11+ site, Fe+2.11+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with five FeO6 octahedra, a cornercorner with one FeO4 tetrahedra, and edges with ten FeO6 octahedra. The corner-sharing octahedra tilt angles range from 3–19°. There are a spread of Fe–O bond distances ranging from 2.11–2.40 Å. In the fifth Fe+2.11+ site, Fe+2.11+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with five FeO6 octahedra, a cornercorner with one PO4 tetrahedra, and edges with ten FeO6 octahedra. The corner-sharing octahedra tilt angles range from 4–18°. There are a spread of Fe–O bond distances ranging from 2.15–2.28 Å. In the sixth Fe+2.11+ site, Fe+2.11+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are a spread of Fe–O bond distances ranging from 1.99–2.19 Å. In the seventh Fe+2.11+ site, Fe+2.11+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with eight FeO6 octahedra and corners with two equivalent FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–60°. There is two shorter (1.89 Å) and two longer (1.92 Å) Fe–O bond length. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with eight FeO6 octahedra and corners with two equivalent PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–63°. There is two shorter (1.56 Å) and two longer (1.74 Å) P–O bond length. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded to four Fe+2.11+ atoms to form distorted OFe4 trigonal pyramids that share a cornercorner with one OFe6 octahedra, corners with two equivalent OFe5 square pyramids, corners with five equivalent OFe4 trigonal pyramids, edges with two equivalent OFe6 octahedra, and an edgeedge with one OFe4 trigonal pyramid. The corner-sharing octahedral tilt angles are 5°. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe+2.11+ and one P5+ atom. In the third O2- site, O2- is bonded to six Fe+2.11+ atoms to form OFe6 octahedra that share corners with four equivalent OFe6 octahedra, a cornercorner with one OFe4 trigonal pyramid, edges with six OFe6 octahedra, and edges with four OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 3–9°. In the fourth O2- site, O2- is bonded in a 6-coordinate geometry to six Fe+2.11+ atoms. In the fifth O2- site, O2- is bonded to six Fe+2.11+ atoms to form OFe6 octahedra that share corners with four equivalent OFe5 square pyramids, edges with six OFe6 octahedra, edges with two equivalent OFe5 square pyramids, and edges with four equivalent OFe4 trigonal pyramids. In the sixth O2- site, O2- is bonded to five Fe+2.11+ atoms to form OFe5 square pyramids that share a cornercorner with one OFe5 square pyramid, edges with four equivalent OFe6 octahedra, and edges with two equivalent OFe5 square pyramids. In the seventh O2- site, O2- is bonded to five Fe+2.11+ atoms to form OFe5 square pyramids that share corners with four equivalent OFe6 octahedra, a cornercorner with one OFe5 square pyramid, corners with four equivalent OFe4 trigonal pyramids, edges with six OFe6 octahedra, and edges with two equivalent OFe5 square pyramids. The corner-sharing octahedral tilt angles are 11°. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Fe+2.11+ and two equivalent P5+ atoms. In the ninth O2- site, O2- is bonded in a trigonal planar geometry to three Fe+2.11+ atoms.