DOI: 10.17188/1741416
title: Materials Data on Fe15O16 by Materials Project

description: Fe15O16 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are six inequivalent Fe+2.13+ sites. In the first Fe+2.13+ site, Fe+2.13+ is bonded to six equivalent O2- atoms to form FeO6 octahedra that share corners with six equivalent FeO6 octahedra, corners with six equivalent FeO4 tetrahedra, and edges with six equivalent FeO6 octahedra. The corner-sharing octahedral tilt angles are 6°. All Fe–O bond lengths are 2.24 Å. In the second Fe+2.13+ site, Fe+2.13+ is bonded to six equivalent O2- atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles are 1°. All Fe–O bond lengths are 2.17 Å. In the third Fe+2.13+ site, Fe+2.13+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent FeO6 octahedra, corners with three equivalent FeO4 tetrahedra, and edges with ten FeO6 octahedra. The corner-sharing octahedra tilt angles range from 3–4°. There are a spread of Fe–O bond distances ranging from 2.06–2.27 Å. In the fourth Fe+2.13+ site, Fe+2.13+ is bonded to four O2- atoms to form a mixture of distorted face and corner-sharing FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–63°. There is one shorter (1.90 Å) and three longer (1.96 Å) Fe–O bond length. In the fifth Fe+2.13+ site, Fe+2.13+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO6 octahedra, edges with nine FeO6 octahedra, and a faceface with one FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 1–6°. There are three shorter (2.11 Å) and three longer (2.29 Å) Fe–O bond lengths. In the sixth Fe+2.13+ site, Fe+2.13+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 3–4°. There are four shorter (2.16 Å) and two longer (2.27 Å) Fe–O bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to four Fe+2.13+ atoms to form distorted OFe4 tetrahedra that share corners with three equivalent OFe6 octahedra, corners with nine equivalent OFe5 square pyramids, and edges with three equivalent OFe6 octahedra. The corner-sharing octahedral tilt angles are 5°. In the second O2- site, O2- is bonded to six Fe+2.13+ atoms to form OFe6 octahedra that share corners with three equivalent OFe6 octahedra, corners with three equivalent OFe4 tetrahedra, edges with nine equivalent OFe6 octahedra, and edges with three equivalent OFe5 square pyramids. The corner-sharing octahedral tilt angles are 0°. In the third O2- site, O2- is bonded to six Fe+2.13+ atoms to form OFe6 octahedra that share corners with three equivalent OFe6 octahedra, corners with three equivalent OFe5 square pyramids, edges with nine OFe6 octahedra, edges with two equivalent OFe5 square pyramids, and an edgeedge with one OFe4 tetrahedra. The corner-sharing octahedral tilt angles are 0°. In the fourth O2- site, O2- is bonded to five Fe+2.13+ atoms to form distorted OFe5 square pyramids that share corners with three equivalent OFe6 octahedra, corners with three equivalent OFe5 square pyramids, corners with three equivalent OFe4 tetrahedra, edges with three OFe6 octahedra, and edges with four equivalent OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 4–8°.