DOI: 10.17188/1285693
title: Materials Data on Fe9(PO4)8 by Materials Project

description: Fe9(PO4)8 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are six inequivalent Fe+2.67+ sites. In the first Fe+2.67+ site, Fe+2.67+ is bonded to five O2- atoms to form FeO5 trigonal bipyramids that share a cornercorner with one FeO6 octahedra, corners with three PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 63°. There are a spread of Fe–O bond distances ranging from 1.88–2.12 Å. In the second Fe+2.67+ site, Fe+2.67+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share a cornercorner with one FeO6 octahedra, corners with four PO4 tetrahedra, corners with two equivalent FeO5 trigonal bipyramids, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. There are a spread of Fe–O bond distances ranging from 1.94–2.48 Å. In the third Fe+2.67+ site, Fe+2.67+ is bonded to five O2- atoms to form FeO5 trigonal bipyramids that share corners with two equivalent FeO6 octahedra and corners with five PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 61–66°. There are a spread of Fe–O bond distances ranging from 1.88–2.08 Å. In the fourth Fe+2.67+ site, Fe+2.67+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (2.01 Å) and two longer (2.10 Å) Fe–O bond lengths. In the fifth Fe+2.67+ site, Fe+2.67+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with two equivalent PO4 tetrahedra, corners with two equivalent FeO5 trigonal bipyramids, and edges with two equivalent PO4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. There are a spread of Fe–O bond distances ranging from 2.05–2.35 Å. In the sixth Fe+2.67+ site, Fe+2.67+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (1.99 Å) and two longer (2.16 Å) Fe–O bond lengths. There are four inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one FeO6 octahedra, corners with three FeO5 trigonal bipyramids, and an edgeedge with one FeO6 octahedra. The corner-sharing octahedral tilt angles are 42°. There are a spread of P–O bond distances ranging from 1.53–1.59 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one FeO6 octahedra and corners with two FeO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 39°. There are a spread of P–O bond distances ranging from 1.53–1.59 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one FeO6 octahedra, a cornercorner with one FeO5 trigonal bipyramid, an edgeedge with one FeO6 octahedra, and an edgeedge with one FeO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 49°. There are a spread of P–O bond distances ranging from 1.52–1.58 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent FeO6 octahedra and corners with two FeO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 43–45°. There are a spread of P–O bond distances ranging from 1.53–1.57 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe+2.67+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe+2.67+ and one P5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two Fe+2.67+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Fe+2.67+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two Fe+2.67+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to one Fe+2.67+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe+2.67+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a bent 120 degrees geometry to one Fe+2.67+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Fe+2.67+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe+2.67+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe+2.67+ and one P5+ atom. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to two Fe+2.67+ and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe+2.67+ and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Fe+2.67+ and one P5+ atom. In the fifteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Fe+2.67+ and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Fe+2.67+ and one P5+ atom.