DOI: 10.17188/1286000
title: Materials Data on Fe7O9 by Materials Project

description: Fe7O9 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twenty-one inequivalent Fe+2.57+ sites. In the first Fe+2.57+ site, Fe+2.57+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of Fe–O bond distances ranging from 1.92–2.01 Å. In the second Fe+2.57+ site, Fe+2.57+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of Fe–O bond distances ranging from 1.98–2.12 Å. In the third Fe+2.57+ site, Fe+2.57+ is bonded to four O2- atoms to form distorted FeO4 tetrahedra that share corners with two FeO5 square pyramids and corners with two FeO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.85–2.00 Å. In the fourth Fe+2.57+ site, Fe+2.57+ is bonded to five O2- atoms to form distorted FeO5 square pyramids that share a cornercorner with one FeO5 square pyramid, corners with three FeO4 tetrahedra, and edges with two FeO5 trigonal bipyramids. There are a spread of Fe–O bond distances ranging from 2.05–2.30 Å. In the fifth Fe+2.57+ site, Fe+2.57+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of Fe–O bond distances ranging from 1.92–2.06 Å. In the sixth Fe+2.57+ site, Fe+2.57+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three FeO5 square pyramids, a cornercorner with one FeO4 tetrahedra, and corners with three FeO5 trigonal bipyramids. There are a spread of Fe–O bond distances ranging from 1.90–1.97 Å. In the seventh Fe+2.57+ site, Fe+2.57+ is bonded to five O2- atoms to form distorted FeO5 trigonal bipyramids that share a cornercorner with one FeO5 square pyramid, corners with two FeO4 tetrahedra, and edges with two FeO5 trigonal bipyramids. There are a spread of Fe–O bond distances ranging from 1.94–2.21 Å. In the eighth Fe+2.57+ site, Fe+2.57+ is bonded to five O2- atoms to form distorted FeO5 square pyramids that share corners with two FeO4 tetrahedra, a cornercorner with one FeO5 trigonal bipyramid, an edgeedge with one FeO6 octahedra, and an edgeedge with one FeO5 square pyramid. There are a spread of Fe–O bond distances ranging from 1.91–2.31 Å. In the ninth Fe+2.57+ site, Fe+2.57+ is bonded to five O2- atoms to form distorted FeO5 square pyramids that share a cornercorner with one FeO5 square pyramid, corners with three FeO4 tetrahedra, an edgeedge with one FeO6 octahedra, and an edgeedge with one FeO5 square pyramid. There are a spread of Fe–O bond distances ranging from 1.89–2.26 Å. In the tenth Fe+2.57+ site, Fe+2.57+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Fe–O bond distances ranging from 1.96–2.03 Å. In the eleventh Fe+2.57+ site, Fe+2.57+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of Fe–O bond distances ranging from 1.92–2.01 Å. In the twelfth Fe+2.57+ site, Fe+2.57+ is bonded to five O2- atoms to form distorted FeO5 trigonal bipyramids that share corners with two FeO4 tetrahedra, a cornercorner with one FeO5 trigonal bipyramid, an edgeedge with one FeO6 octahedra, and edges with two FeO5 trigonal bipyramids. There are a spread of Fe–O bond distances ranging from 2.05–2.21 Å. In the thirteenth Fe+2.57+ site, Fe+2.57+ is bonded to five O2- atoms to form distorted FeO5 trigonal bipyramids that share corners with three FeO4 tetrahedra, a cornercorner with one FeO5 trigonal bipyramid, and edges with two FeO5 trigonal bipyramids. There are a spread of Fe–O bond distances ranging from 1.93–2.13 Å. In the fourteenth Fe+2.57+ site, Fe+2.57+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two FeO4 tetrahedra, edges with two FeO5 square pyramids, and edges with two FeO5 trigonal bipyramids. There are a spread of Fe–O bond distances ranging from 2.02–2.09 Å. In the fifteenth Fe+2.57+ site, Fe+2.57+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Fe–O bond distances ranging from 1.97–2.58 Å. In the sixteenth Fe+2.57+ site, Fe+2.57+ is bonded to four O2- atoms to form FeO4 tetrahedra that share a cornercorner with one FeO6 octahedra, a cornercorner with one FeO5 square pyramid, and corners with five FeO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 50°. There are a spread of Fe–O bond distances ranging from 1.91–1.97 Å. In the seventeenth Fe+2.57+ site, Fe+2.57+ is bonded to four O2- atoms to form FeO4 tetrahedra that share a cornercorner with one FeO6 octahedra, corners with two FeO5 square pyramids, a cornercorner with one FeO4 tetrahedra, and corners with four FeO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 52°. There are a spread of Fe–O bond distances ranging from 1.90–1.99 Å. In the eighteenth Fe+2.57+ site, Fe+2.57+ is bonded in a distorted see-saw-like geometry to four O2- atoms. There are a spread of Fe–O bond distances ranging from 1.89–2.04 Å. In the nineteenth Fe+2.57+ site, Fe+2.57+ is bonded to five O2- atoms to form FeO5 trigonal bipyramids that share corners with two FeO4 tetrahedra, a cornercorner with one FeO5 trigonal bipyramid, an edgeedge with one FeO6 octahedra, an edgeedge with one FeO5 square pyramid, and an edgeedge with one FeO5 trigonal bipyramid. There are a spread of Fe–O bond distances ranging from 1.92–2.08 Å. In the twentieth Fe+2.57+ site, Fe+2.57+ is bonded to five O2- atoms to form distorted FeO5 trigonal bipyramids that share corners with three FeO4 tetrahedra, a cornercorner with one FeO5 trigonal bipyramid, an edgeedge with one FeO5 square pyramid, and an edgeedge with one FeO5 trigonal bipyramid. There are a spread of Fe–O bond distances ranging from 1.93–2.15 Å. In the twenty-first Fe+2.57+ site, Fe+2.57+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of Fe–O bond distances ranging from 1.92–1.99 Å. There are twenty-seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three Fe+2.57+ atoms. In the second O2- site, O2- is bonded in a distorted T-shaped geometry to three Fe+2.57+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to three Fe+2.57+ atoms. In the fourth O2- site, O2- is bonded in a trigonal planar geometry to three Fe+2.57+ atoms. In the fifth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Fe+2.57+ atoms. In the sixth O2- site, O2- is bonded in a trigonal planar geometry to three Fe+2.57+ atoms. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to three Fe+2.57+ atoms. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Fe+2.57+ atoms. In the ninth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Fe+2.57+ atoms. In the tenth O2- site, O2- is bonded in a trigonal planar geometry to three Fe+2.57+ atoms. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to three Fe+2.57+ atoms. In the twelfth O2- site, O2- is bonded in a distorted tetrahedral geometry to four Fe+2.57+ atoms. In the thirteenth O2- site, O2- is bonded in a 3-coordinate geometry to three Fe+2.57+ atoms. In the fourteenth O2- site, O2- is bonded in a 4-coordinate geometry to four Fe+2.57+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Fe+2.57+ atoms. In the sixteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Fe+2.57+ atoms. In the seventeenth O2- site, O2- is bonded in a trigonal planar geometry to three Fe+2.57+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Fe+2.57+ atoms. In the nineteenth O2- site, O2- is bonded to four Fe+2.57+ atoms to form edge-sharing OFe4 tetrahedra. In the twentieth O2- site, O2- is bonded to four Fe+2.57+ atoms to form distorted edge-sharing OFe4 trigonal pyramids. In the twenty-first O2- site, O2- is bonded in a trigonal planar geometry to three Fe+2.57+ atoms. In the twenty-second O2- site, O2- is bonded in a trigonal planar geometry to three Fe+2.57+ atoms. In the twenty-third O2- site, O2- is bonded in a distorted trigonal planar geometry to three Fe+2.57+ atoms. In the twenty-fourth O2- site, O2- is bonded to four Fe+2.57+ atoms to form distorted edge-sharing OFe4 trigonal pyramids. In the twenty-fifth O2- site, O2- is bonded in a trigonal planar geometry to three Fe+2.57+ atoms. In the twenty-sixth O2- site, O2- is bonded in a trigonal planar geometry to three Fe+2.57+ atoms. In the twenty-seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Fe+2.57+ atoms.