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DOE OSTI2020

Materials Data on Fe35O36 by Materials Project

Fe35O36 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are thirty-five inequivalent Fe+2.06+ sites. In the first Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 2–10°. There are a spread of Fe–O bond distances ranging from 2.11–2.33 Å. In the second Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 3–8°. There are a spread of Fe–O bond distances ranging from 2.13–2.32 Å. In the third Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 2–7°. There are a spread of Fe–O bond distances ranging from 2.13–2.27 Å. In the fourth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 2–7°. There are a spread of Fe–O bond distances ranging from 2.12–2.24 Å. In the fifth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 4–11°. There are a spread of Fe–O bond distances ranging from 2.11–2.31 Å. In the sixth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 1–17°. There are a spread of Fe–O bond distances ranging from 2.10–2.24 Å. In the seventh Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 2–10°. There are a spread of Fe–O bond distances ranging from 2.09–2.30 Å. In the eighth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 2–4°. There are a spread of Fe–O bond distances ranging from 2.03–2.20 Å. In the ninth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 1–10°. There are a spread of Fe–O bond distances ranging from 2.12–2.22 Å. In the tenth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 3–17°. There are a spread of Fe–O bond distances ranging from 2.08–2.33 Å. In the eleventh Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 2–9°. There are a spread of Fe–O bond distances ranging from 2.12–2.27 Å. In the twelfth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 3–9°. There are a spread of Fe–O bond distances ranging from 2.12–2.25 Å. In the thirteenth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 2–10°. There are a spread of Fe–O bond distances ranging from 2.07–2.26 Å. In the fourteenth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 1–5°. There are a spread of Fe–O bond distances ranging from 2.04–2.08 Å. In the fifteenth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 1–7°. There are a spread of Fe–O bond distances ranging from 2.14–2.20 Å. In the sixteenth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 4–13°. There are a spread of Fe–O bond distances ranging from 2.07–2.30 Å. In the seventeenth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 1–8°. There are a spread of Fe–O bond distances ranging from 2.07–2.31 Å. In the eighteenth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 5–11°. There are a spread of Fe–O bond distances ranging from 2.09–2.25 Å. In the nineteenth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 3–9°. There are a spread of Fe–O bond distances ranging from 2.10–2.31 Å. In the twentieth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 2–12°. There are a spread of Fe–O bond distances ranging from 2.09–2.26 Å. In the twenty-first Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 1–6°. There are a spread of Fe–O bond distances ranging from 2.03–2.13 Å. In the twenty-second Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 7–12°. There are a spread of Fe–O bond distances ranging from 2.08–2.27 Å. In the twenty-third Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 4–14°. There are a spread of Fe–O bond distances ranging from 2.12–2.32 Å. In the twenty-fourth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 3–8°. There are a spread of Fe–O bond distances ranging from 2.07–2.24 Å. In the twenty-fifth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 1–13°. There are a spread of Fe–O bond distances ranging from 2.10–2.32 Å. In the twenty-sixth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 2–10°. There are a spread of Fe–O bond distances ranging from 2.13–2.22 Å. In the twenty-seventh Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 1–6°. There are a spread of Fe–O bond distances ranging from 2.10–2.37 Å. In the twenty-eighth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 2–9°. There are a spread of Fe–O bond distances ranging from 2.13–2.24 Å. In the twenty-ninth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 2–9°. There are a spread of Fe–O bond distances ranging from 2.15–2.27 Å. In the thirtieth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 2–4°. There are a spread of Fe–O bond distances ranging from 2.12–2.24 Å. In the thirty-first Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 3–14°. There are a spread of Fe–O bond distances ranging from 2.09–2.25 Å. In the thirty-second Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 1–4°. There are a spread of Fe–O bond distances ranging from 2.12–2.29 Å. In the thirty-third Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 2–10°. There are a spread of Fe–O bond distances ranging from 2.15–2.24 Å. In the thirty-fourth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 1–10°. There are a spread of Fe–O bond distances ranging from 2.08–2.32 Å. In the thirty-fifth Fe+2.06+ site, Fe+2.06+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 1–11°. There are a spread of Fe–O bond distances ranging from 2.09–2.33 Å. There are thirty-six inequivalent O2- sites. In the first O2- site, O2- is bonded to six Fe+2.06+ atoms to form OFe6 octahedra that share corners with six OFe6 octahedra, edges with nine OFe6 octahedra, and edges with three OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 1–12°. In the second O2- site, O2- is bonded to six Fe+2.06+ atoms to form OFe6 octahedra that share corners with five OFe6 octahedra, a cornercorner with one OFe5 square pyramid, edges with eleven OFe6 octahedra, and an edgeedge with one OFe5 square pyramid. The corner-sharing octahedra tilt angles range from 2–5°. In the third O2- site, O2- is bonded to six Fe+2.06+ atoms to form OFe6 octahedra that share corners with six OFe6 octahedra, edges with nine OFe6 octahedra, and edges with three OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 4–9°. In the fourth O2- site, O2- is bonded to six Fe+2.06+ atoms to form OFe6 octahedra that share corners with five OFe6 octahedra, a cornercorner with one OFe5 square pyramid, edges with eleven OFe6 octahedra, and an edgeedge with one OFe5 square pyramid. The corner-sharing octahedra tilt angles range from 1–7°. In the fifth O2- site, O2- is bonded to six Fe+2.06+ atoms to form OFe6 octahedra that share corners with four OFe6 octahedra, corners with two OFe5 square pyramids, edges with ten OFe6 octahedra, and edges with two OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 2–7°. In the sixth O2- site, O2- is bonded to five Fe+2.06+ atoms to form OFe5 square pyramids that share corners with five OFe6 octahedra, corners with four OFe5 square pyramids, and edges with eight OFe6 octahedra. The corner-sharing octahedra tilt angles range from 1–12°. In the seventh O2- site, O2- is bonded to five Fe+2.06+ atoms to form OFe5 square pyramids that share corners with five OFe6 octahedra, corners with four OFe5 square pyramids, and edges with eight OFe6 octahedra. The corner-sharing octahedra tilt angles range from 1–10°. In the eighth O2- site, O2- is bonded to six Fe+2.06+ atoms to form OFe6 octahedra that share corners with five OFe6 octahedra, a cornercorner with one OFe5 square pyramid, edges with eleven OFe6 octahedra, and an edgeedge with one OFe5 square pyramid. The corner-sharing octahedra tilt angles range from 2–4°. In the ninth O2- site, O2- is bonded to six Fe+2.06+ atoms to form OFe6 octahedra that share corners with four OFe6 octahedra, corners with two OFe5 square pyramids, edges with eleven OFe6 octahedra, and an edgeedge with one OFe5 square pyramid. The corner-sharing octahedra tilt angles range from 1–4°. In the tenth O2- site, O2- is bonded to six Fe+2.06+ atoms to form OFe6 octahedra that share corners with five OFe6 octahedra, a cornercorner with one OFe5 square pyramid, edges with eleven OFe6 octahedra, and an edgeedge with one OFe5 square pyramid.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Fe17O18 by Materials Project

Fe17O18 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are nine inequivalent Fe+2.12+ sites. In the first Fe+2.12+ site, Fe+2.12+ 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 2–9°. There are a spread of Fe–O bond distances ranging from 2.12–2.24 Å. In the second Fe+2.12+ site, Fe+2.12+ 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 2–12°. There are a spread of Fe–O bond distances ranging from 2.14–2.27 Å. In the third Fe+2.12+ site, Fe+2.12+ 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 3–12°. There are a spread of Fe–O bond distances ranging from 2.02–2.15 Å. In the fourth Fe+2.12+ site, Fe+2.12+ 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 1–11°. There are a spread of Fe–O bond distances ranging from 2.12–2.34 Å. In the fifth Fe+2.12+ site, Fe+2.12+ 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 6–14°. There are a spread of Fe–O bond distances ranging from 2.08–2.29 Å. In the sixth Fe+2.12+ site, Fe+2.12+ 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 1–9°. There are a spread of Fe–O bond distances ranging from 2.11–2.36 Å. In the seventh Fe+2.12+ site, Fe+2.12+ 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 6–11°. There are a spread of Fe–O bond distances ranging from 2.14–2.26 Å. In the eighth Fe+2.12+ site, Fe+2.12+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles are 3°. There are a spread of Fe–O bond distances ranging from 2.04–2.31 Å. In the ninth Fe+2.12+ site, Fe+2.12+ 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 2–14°. There are a spread of Fe–O bond distances ranging from 2.14–2.26 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded to six Fe+2.12+ atoms to form OFe6 octahedra that share corners with five OFe6 octahedra, a cornercorner with one OFe5 square pyramid, edges with eight OFe6 octahedra, and edges with four OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 3–8°. In the second O2- site, O2- is bonded to six Fe+2.12+ atoms to form OFe6 octahedra that share corners with five OFe6 octahedra, a cornercorner with one OFe5 square pyramid, edges with eight OFe6 octahedra, and edges with four OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 2–9°. In the third O2- site, O2- is bonded to six Fe+2.12+ atoms to form OFe6 octahedra that share corners with five OFe6 octahedra, a cornercorner with one OFe5 square pyramid, edges with eight OFe6 octahedra, and edges with four OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 2–9°. In the fourth O2- site, O2- is bonded to five Fe+2.12+ atoms to form OFe5 square pyramids that share corners with four OFe6 octahedra, corners with five OFe5 square pyramids, edges with seven OFe6 octahedra, and an edgeedge with one OFe5 square pyramid. The corner-sharing octahedra tilt angles range from 5–10°. In the fifth O2- site, O2- is bonded to six Fe+2.12+ atoms to form OFe6 octahedra that share corners with four OFe6 octahedra, corners with two OFe5 square pyramids, edges with seven OFe6 octahedra, and edges with five OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 2–8°. In the sixth O2- site, O2- is bonded to six Fe+2.12+ atoms to form OFe6 octahedra that share corners with two OFe6 octahedra, corners with four OFe5 square pyramids, edges with nine OFe6 octahedra, and edges with three OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 0–2°. In the seventh O2- site, O2- is bonded to five Fe+2.12+ atoms to form OFe5 square pyramids that share corners with three OFe6 octahedra, corners with six OFe5 square pyramids, and edges with eight OFe6 octahedra. The corner-sharing octahedra tilt angles range from 8–11°. In the eighth O2- site, O2- is bonded to five Fe+2.12+ atoms to form OFe5 square pyramids that share corners with five OFe6 octahedra, corners with four OFe5 square pyramids, and edges with eight OFe6 octahedra. The corner-sharing octahedra tilt angles range from 1–9°. In the ninth O2- site, O2- is bonded to six Fe+2.12+ atoms to form OFe6 octahedra that share corners with three OFe6 octahedra, corners with three OFe5 square pyramids, edges with nine OFe6 octahedra, and edges with three OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 0–8°.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Fe23O25 by Materials Project

Fe23O25 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are twelve inequivalent Fe+2.17+ sites. In the first Fe+2.17+ site, Fe+2.17+ 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 7–17°. There are a spread of Fe–O bond distances ranging from 2.10–2.33 Å. In the second Fe+2.17+ site, Fe+2.17+ 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 0–14°. There are a spread of Fe–O bond distances ranging from 2.10–2.33 Å. In the third Fe+2.17+ site, Fe+2.17+ 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 4–14°. There are a spread of Fe–O bond distances ranging from 2.09–2.26 Å. In the fourth Fe+2.17+ site, Fe+2.17+ 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 7–17°. There are a spread of Fe–O bond distances ranging from 2.09–2.24 Å. In the fifth Fe+2.17+ site, Fe+2.17+ 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 6–9°. There are a spread of Fe–O bond distances ranging from 2.01–2.18 Å. In the sixth Fe+2.17+ site, Fe+2.17+ 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 4–13°. There are a spread of Fe–O bond distances ranging from 2.14–2.23 Å. In the seventh Fe+2.17+ site, Fe+2.17+ 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 5–15°. There are a spread of Fe–O bond distances ranging from 2.10–2.39 Å. In the eighth Fe+2.17+ site, Fe+2.17+ 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 5–13°. There are a spread of Fe–O bond distances ranging from 2.11–2.21 Å. In the ninth Fe+2.17+ site, Fe+2.17+ 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 5–14°. There are a spread of Fe–O bond distances ranging from 2.11–2.24 Å. In the tenth Fe+2.17+ site, Fe+2.17+ 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 0–12°. There are a spread of Fe–O bond distances ranging from 2.04–2.20 Å. In the eleventh Fe+2.17+ site, Fe+2.17+ 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 4–15°. There are a spread of Fe–O bond distances ranging from 2.10–2.23 Å. In the twelfth Fe+2.17+ site, Fe+2.17+ 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 0–14°. There are a spread of Fe–O bond distances ranging from 2.12–2.25 Å. There are thirteen inequivalent O2- sites. In the first O2- site, O2- is bonded to six Fe+2.17+ atoms to form OFe6 octahedra that share corners with three OFe6 octahedra, corners with three OFe5 square pyramids, edges with six OFe6 octahedra, and edges with six OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 6–9°. In the second O2- site, O2- is bonded to six Fe+2.17+ atoms to form OFe6 octahedra that share corners with five OFe6 octahedra, a cornercorner with one OFe5 square pyramid, edges with five OFe6 octahedra, and edges with seven OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 0–11°. In the third O2- site, O2- is bonded to five Fe+2.17+ atoms to form OFe5 square pyramids that share corners with two OFe6 octahedra, corners with seven OFe5 square pyramids, edges with six OFe6 octahedra, and edges with two OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 4–9°. In the fourth O2- site, O2- is bonded to five Fe+2.17+ atoms to form OFe5 square pyramids that share corners with two equivalent OFe6 octahedra, corners with seven OFe5 square pyramids, edges with seven OFe6 octahedra, and an edgeedge with one OFe5 square pyramid. The corner-sharing octahedra tilt angles range from 7–11°. In the fifth O2- site, O2- is bonded to five Fe+2.17+ atoms to form OFe5 square pyramids that share corners with four OFe6 octahedra, corners with five OFe5 square pyramids, edges with seven OFe6 octahedra, and an edgeedge with one OFe5 square pyramid. The corner-sharing octahedra tilt angles range from 4–10°. In the sixth O2- site, O2- is bonded to six Fe+2.17+ atoms to form OFe6 octahedra that share corners with three OFe6 octahedra, corners with three OFe5 square pyramids, edges with six OFe6 octahedra, and edges with six OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 2–11°. In the seventh O2- site, O2- is bonded to six Fe+2.17+ atoms to form OFe6 octahedra that share corners with six OFe6 octahedra, edges with six OFe6 octahedra, and edges with six OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 2–7°. In the eighth O2- site, O2- is bonded to six Fe+2.17+ atoms to form OFe6 octahedra that share corners with three OFe6 octahedra, corners with three OFe5 square pyramids, edges with six OFe6 octahedra, and edges with six OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 4–8°. In the ninth O2- site, O2- is bonded to five Fe+2.17+ atoms to form OFe5 square pyramids that share corners with three OFe6 octahedra, corners with six OFe5 square pyramids, edges with seven OFe6 octahedra, and an edgeedge with one OFe5 square pyramid. The corner-sharing octahedra tilt angles range from 7–9°. In the tenth O2- site, O2- is bonded to six Fe+2.17+ atoms to form OFe6 octahedra that share corners with three OFe6 octahedra, corners with three OFe5 square pyramids, edges with six OFe6 octahedra, and edges with six OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 8–10°. In the eleventh O2- site, O2- is bonded to five Fe+2.17+ atoms to form OFe5 square pyramids that share corners with three OFe6 octahedra, corners with six OFe5 square pyramids, edges with seven OFe6 octahedra, and an edgeedge with one OFe5 square pyramid. The corner-sharing octahedra tilt angles range from 10–13°. In the twelfth O2- site, O2- is bonded to six Fe+2.17+ atoms to form OFe6 octahedra that share corners with three OFe6 octahedra, corners with three OFe5 square pyramids, edges with six OFe6 octahedra, and edges with six OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 6–7°. In the thirteenth O2- site, O2- is bonded to five Fe+2.17+ atoms to form OFe5 square pyramids that share corners with two OFe6 octahedra, corners with seven OFe5 square pyramids, edges with six OFe6 octahedra, and edges with two OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 6–8°.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Fe7O9 by Materials Project

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.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on FeO2 by Materials Project

FeO2 is trigonal omega-like structured and crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. Fe is bonded to six equivalent O atoms to form edge-sharing FeO6 octahedra. There is two shorter (1.87 Å) and four longer (2.03 Å) Fe–O bond length. O is bonded in a distorted T-shaped geometry to three equivalent Fe atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on FeO by Materials Project

FeO is Halite, Rock Salt structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Fe2+ 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 0°. There are two shorter (2.08 Å) and four longer (2.27 Å) Fe–O bond lengths. O2- is bonded to six equivalent Fe2+ atoms to form a mixture of edge and corner-sharing OFe6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Fe3O4 by Materials Project

Fe3O4 crystallizes in the monoclinic Pc 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 in a 4-coordinate geometry to eight O2- atoms. There are a spread of Fe–O bond distances ranging from 2.10–2.75 Å. In the second Fe+2.67+ site, Fe+2.67+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Fe–O bond distances ranging from 2.11–2.35 Å. In the third Fe+2.67+ site, Fe+2.67+ 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 1–54°. There are a spread of Fe–O bond distances ranging from 1.99–2.11 Å. In the fourth Fe+2.67+ site, Fe+2.67+ 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 1–54°. There are a spread of Fe–O bond distances ranging from 1.96–2.14 Å. In the fifth Fe+2.67+ site, Fe+2.67+ 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 1–56°. There are a spread of Fe–O bond distances ranging from 1.98–2.13 Å. In the sixth Fe+2.67+ site, Fe+2.67+ 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 1–56°. There are a spread of Fe–O bond distances ranging from 1.97–2.17 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to five Fe+2.67+ atoms to form distorted OFe5 trigonal bipyramids that share corners with five OFe4 tetrahedra, corners with two equivalent OFe5 trigonal bipyramids, an edgeedge with one OFe4 tetrahedra, and edges with three OFe5 trigonal bipyramids. In the second O2- site, O2- is bonded in a 5-coordinate geometry to five Fe+2.67+ atoms. In the third O2- site, O2- is bonded to five Fe+2.67+ atoms to form distorted OFe5 trigonal bipyramids that share corners with five OFe4 tetrahedra, corners with two equivalent OFe5 trigonal bipyramids, an edgeedge with one OFe4 tetrahedra, and edges with three OFe5 trigonal bipyramids. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to five Fe+2.67+ atoms. In the fifth O2- site, O2- is bonded to four Fe+2.67+ atoms to form distorted OFe4 tetrahedra that share corners with two equivalent OFe4 tetrahedra, corners with eight OFe5 trigonal bipyramids, and edges with two OFe5 trigonal bipyramids. In the sixth O2- site, O2- is bonded to four Fe+2.67+ atoms to form distorted OFe4 tetrahedra that share corners with two equivalent OFe4 tetrahedra and corners with two OFe5 trigonal bipyramids. In the seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to five Fe+2.67+ atoms. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to five Fe+2.67+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Fe7O8 by Materials Project

Fe7O8 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are fourteen inequivalent Fe+2.29+ sites. In the first Fe+2.29+ site, Fe+2.29+ 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 7–10°. There are a spread of Fe–O bond distances ranging from 2.15–2.22 Å. In the second Fe+2.29+ site, Fe+2.29+ 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 5–9°. There are a spread of Fe–O bond distances ranging from 2.13–2.27 Å. In the third Fe+2.29+ site, Fe+2.29+ 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 6–10°. There are a spread of Fe–O bond distances ranging from 2.14–2.21 Å. In the fourth Fe+2.29+ site, Fe+2.29+ 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 5–11°. There are a spread of Fe–O bond distances ranging from 2.14–2.22 Å. In the fifth Fe+2.29+ site, Fe+2.29+ 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 6–9°. There are a spread of Fe–O bond distances ranging from 2.17–2.20 Å. In the sixth Fe+2.29+ site, Fe+2.29+ 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 5–11°. There are a spread of Fe–O bond distances ranging from 2.17–2.21 Å. In the seventh Fe+2.29+ site, Fe+2.29+ 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 1–8°. There are a spread of Fe–O bond distances ranging from 2.06–2.16 Å. In the eighth Fe+2.29+ site, Fe+2.29+ 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 2–8°. There are a spread of Fe–O bond distances ranging from 2.08–2.14 Å. In the ninth Fe+2.29+ site, Fe+2.29+ 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 5–10°. There are a spread of Fe–O bond distances ranging from 2.10–2.29 Å. In the tenth Fe+2.29+ site, Fe+2.29+ 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 5–10°. There are a spread of Fe–O bond distances ranging from 2.09–2.30 Å. In the eleventh Fe+2.29+ site, Fe+2.29+ 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 2–8°. There are a spread of Fe–O bond distances ranging from 2.19–2.32 Å. In the twelfth Fe+2.29+ site, Fe+2.29+ 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 1–8°. There are a spread of Fe–O bond distances ranging from 2.19–2.32 Å. In the thirteenth Fe+2.29+ site, Fe+2.29+ is bonded to six O2- atoms to form edge-sharing FeO6 octahedra. There are three shorter (2.04 Å) and three longer (2.05 Å) Fe–O bond lengths. In the fourteenth Fe+2.29+ site, Fe+2.29+ is bonded to six O2- atoms to form edge-sharing FeO6 octahedra. There are four shorter (2.04 Å) and two longer (2.05 Å) Fe–O bond lengths. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded to six Fe+2.29+ atoms to form OFe6 octahedra that share corners with six OFe6 octahedra and edges with twelve OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 0–3°. In the second O2- site, O2- is bonded to six Fe+2.29+ atoms to form OFe6 octahedra that share corners with six OFe6 octahedra and edges with twelve OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 0–3°. In the third O2- site, O2- is bonded to six Fe+2.29+ atoms to form OFe6 octahedra that share corners with six OFe6 octahedra and edges with twelve OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 0–3°. In the fourth O2- site, O2- is bonded to six Fe+2.29+ atoms to form OFe6 octahedra that share corners with six OFe6 octahedra and edges with twelve OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 0–3°. In the fifth O2- site, O2- is bonded to five Fe+2.29+ atoms to form OFe5 square pyramids that share corners with nine OFe5 square pyramids, edges with four OFe6 octahedra, and edges with four OFe5 square pyramids. In the sixth O2- site, O2- is bonded to five Fe+2.29+ atoms to form OFe5 square pyramids that share corners with nine OFe5 square pyramids, edges with four OFe6 octahedra, and edges with four OFe5 square pyramids. In the seventh O2- site, O2- is bonded to five Fe+2.29+ atoms to form OFe5 square pyramids that share corners with nine OFe5 square pyramids, edges with four OFe6 octahedra, and edges with four OFe5 square pyramids. In the eighth O2- site, O2- is bonded to five Fe+2.29+ atoms to form OFe5 square pyramids that share corners with nine OFe5 square pyramids, edges with four OFe6 octahedra, and edges with four OFe5 square pyramids. In the ninth O2- site, O2- is bonded to five Fe+2.29+ atoms to form OFe5 square pyramids that share corners with nine OFe5 square pyramids, edges with four OFe6 octahedra, and edges with four OFe5 square pyramids. In the tenth O2- site, O2- is bonded to five Fe+2.29+ atoms to form OFe5 square pyramids that share corners with nine OFe5 square pyramids, edges with four OFe6 octahedra, and edges with four OFe5 square pyramids. In the eleventh O2- site, O2- is bonded to five Fe+2.29+ atoms to form OFe5 square pyramids that share corners with nine OFe5 square pyramids, edges with four OFe6 octahedra, and edges with four OFe5 square pyramids. In the twelfth O2- site, O2- is bonded to five Fe+2.29+ atoms to form OFe5 square pyramids that share corners with nine OFe5 square pyramids, edges with four OFe6 octahedra, and edges with four OFe5 square pyramids. In the thirteenth O2- site, O2- is bonded to five Fe+2.29+ atoms to form OFe5 square pyramids that share corners with nine OFe5 square pyramids, edges with four OFe6 octahedra, and edges with four OFe5 square pyramids. In the fourteenth O2- site, O2- is bonded to five Fe+2.29+ atoms to form OFe5 square pyramids that share corners with nine OFe5 square pyramids, edges with four OFe6 octahedra, and edges with four OFe5 square pyramids. In the fifteenth O2- site, O2- is bonded to five Fe+2.29+ atoms to form OFe5 square pyramids that share corners with nine OFe5 square pyramids, edges with four OFe6 octahedra, and edges with four OFe5 square pyramids. In the sixteenth O2- site, O2- is bonded to five Fe+2.29+ atoms to form OFe5 square pyramids that share corners with nine OFe5 square pyramids, edges with four OFe6 octahedra, and edges with four OFe5 square pyramids.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Fe3O4 by Materials Project

Fe3O4 crystallizes in the triclinic P1 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 six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 7–56°. There are a spread of Fe–O bond distances ranging from 2.01–2.10 Å. In the second Fe+2.67+ site, Fe+2.67+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 7–55°. There are a spread of Fe–O bond distances ranging from 1.94–2.13 Å. In the third Fe+2.67+ site, Fe+2.67+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 6–56°. There are a spread of Fe–O bond distances ranging from 1.97–2.11 Å. In the fourth Fe+2.67+ site, Fe+2.67+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 6–55°. There are a spread of Fe–O bond distances ranging from 1.98–2.13 Å. In the fifth Fe+2.67+ site, Fe+2.67+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Fe–O bond distances ranging from 2.11–2.53 Å. In the sixth Fe+2.67+ site, Fe+2.67+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Fe–O bond distances ranging from 2.13–2.52 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to four Fe+2.67+ atoms to form distorted OFe4 tetrahedra that share corners with two equivalent OFe5 square pyramids, corners with two equivalent OFe4 tetrahedra, corners with ten OFe5 trigonal bipyramids, edges with two equivalent OFe5 square pyramids, and edges with two OFe5 trigonal bipyramids. In the second O2- site, O2- is bonded to four Fe+2.67+ atoms to form distorted OFe4 tetrahedra that share corners with two equivalent OFe5 square pyramids, corners with two equivalent OFe4 tetrahedra, corners with ten OFe5 trigonal bipyramids, edges with two equivalent OFe5 square pyramids, and edges with two OFe5 trigonal bipyramids. In the third O2- site, O2- is bonded to five Fe+2.67+ atoms to form distorted OFe5 trigonal bipyramids that share corners with two equivalent OFe5 square pyramids, corners with five OFe4 tetrahedra, corners with two equivalent OFe5 trigonal bipyramids, edges with three equivalent OFe5 square pyramids, an edgeedge with one OFe4 tetrahedra, and edges with five OFe5 trigonal bipyramids. In the fourth O2- site, O2- is bonded to five Fe+2.67+ atoms to form distorted OFe5 trigonal bipyramids that share corners with six OFe5 square pyramids, corners with five OFe4 tetrahedra, corners with two equivalent OFe5 trigonal bipyramids, an edgeedge with one OFe5 square pyramid, an edgeedge with one OFe4 tetrahedra, and edges with five OFe5 trigonal bipyramids. In the fifth O2- site, O2- is bonded to five Fe+2.67+ atoms to form distorted OFe5 trigonal bipyramids that share corners with six OFe5 square pyramids, corners with five OFe4 tetrahedra, corners with two equivalent OFe5 trigonal bipyramids, an edgeedge with one OFe5 square pyramid, an edgeedge with one OFe4 tetrahedra, and edges with five OFe5 trigonal bipyramids. In the sixth O2- site, O2- is bonded to five Fe+2.67+ atoms to form distorted OFe5 trigonal bipyramids that share corners with two equivalent OFe5 square pyramids, corners with five OFe4 tetrahedra, corners with two equivalent OFe5 trigonal bipyramids, edges with three equivalent OFe5 square pyramids, an edgeedge with one OFe4 tetrahedra, and edges with five OFe5 trigonal bipyramids. In the seventh O2- site, O2- is bonded to five Fe+2.67+ atoms to form distorted OFe5 square pyramids that share corners with two equivalent OFe4 tetrahedra, corners with eight OFe5 trigonal bipyramids, edges with two equivalent OFe5 square pyramids, edges with two equivalent OFe4 tetrahedra, and edges with four OFe5 trigonal bipyramids. In the eighth O2- site, O2- is bonded to five Fe+2.67+ atoms to form distorted OFe5 square pyramids that share corners with two equivalent OFe4 tetrahedra, corners with eight OFe5 trigonal bipyramids, edges with two equivalent OFe5 square pyramids, edges with two equivalent OFe4 tetrahedra, and edges with four OFe5 trigonal bipyramids.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Fe3O4 by Materials Project

Fe3O4 is Spinel-derived structured and crystallizes in the monoclinic P2/m space group. The structure is three-dimensional. there are seven inequivalent Fe+2.67+ sites. In the first Fe+2.67+ site, Fe+2.67+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra and edges with six FeO6 octahedra. There are two shorter (2.10 Å) and four longer (2.15 Å) Fe–O bond lengths. In the second Fe+2.67+ site, Fe+2.67+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra and edges with six FeO6 octahedra. There are four shorter (2.05 Å) and two longer (2.07 Å) Fe–O bond lengths. In the third Fe+2.67+ site, Fe+2.67+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra and edges with six FeO6 octahedra. There are two shorter (2.05 Å) and four longer (2.06 Å) Fe–O bond lengths. In the fourth Fe+2.67+ site, Fe+2.67+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra and edges with six FeO6 octahedra. There are two shorter (2.08 Å) and four longer (2.16 Å) Fe–O bond lengths. In the fifth Fe+2.67+ site, Fe+2.67+ is bonded to four O2- atoms to form corner-sharing FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–59°. There is one shorter (1.91 Å) and three longer (1.94 Å) Fe–O bond length. In the sixth Fe+2.67+ site, Fe+2.67+ is bonded to four O2- atoms to form corner-sharing FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–59°. There is three shorter (1.92 Å) and one longer (1.95 Å) Fe–O bond length. In the seventh Fe+2.67+ site, Fe+2.67+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra and edges with six FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.05–2.12 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe+2.67+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Fe+2.67+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Fe+2.67+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe+2.67+ atoms. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe+2.67+ atoms. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe+2.67+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Fe2O3 by Materials Project

Fe2O3 crystallizes in the triclinic P1 space group. The structure is two-dimensional and consists of one Fe2O3 sheet oriented in the (1, 1, -1) direction. there are sixteen inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded in a 3-coordinate geometry to two Fe3+ and four O2- atoms. There are one shorter (2.07 Å) and one longer (2.08 Å) Fe–Fe bond lengths. There are a spread of Fe–O bond distances ranging from 2.01–2.55 Å. In the second Fe3+ site, Fe3+ is bonded in a 6-coordinate geometry to one Fe3+ and six O2- atoms. The Fe–Fe bond length is 2.05 Å. There are a spread of Fe–O bond distances ranging from 1.73–2.43 Å. In the third Fe3+ site, Fe3+ is bonded in a 3-coordinate geometry to two Fe3+ and five O2- atoms. The Fe–Fe bond length is 2.03 Å. There are a spread of Fe–O bond distances ranging from 2.01–2.54 Å. In the fourth Fe3+ site, Fe3+ is bonded in a distorted single-bond geometry to three O2- atoms. There are a spread of Fe–O bond distances ranging from 1.47–2.15 Å. In the fifth Fe3+ site, Fe3+ is bonded in a 3-coordinate geometry to five O2- atoms. There are a spread of Fe–O bond distances ranging from 1.50–2.22 Å. In the sixth Fe3+ site, Fe3+ is bonded in a 1-coordinate geometry to three O2- atoms. There are a spread of Fe–O bond distances ranging from 1.45–2.13 Å. In the seventh Fe3+ site, Fe3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Fe–O bond distances ranging from 1.80–2.25 Å. In the eighth Fe3+ site, Fe3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Fe–O bond distances ranging from 1.87–2.16 Å. In the ninth Fe3+ site, Fe3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Fe–O bond distances ranging from 1.52–2.18 Å. In the tenth Fe3+ site, Fe3+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Fe–O bond distances ranging from 1.82–2.25 Å. In the eleventh Fe3+ site, Fe3+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Fe–O bond distances ranging from 1.85–2.21 Å. In the twelfth Fe3+ site, Fe3+ is bonded in a 6-coordinate geometry to one Fe3+ and six O2- atoms. There are a spread of Fe–O bond distances ranging from 1.71–2.44 Å. In the thirteenth Fe3+ site, Fe3+ is bonded in a 2-coordinate geometry to two Fe3+ and eight O2- atoms. There are a spread of Fe–O bond distances ranging from 2.03–2.53 Å. In the fourteenth Fe3+ site, Fe3+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Fe–O bond distances ranging from 1.74–2.11 Å. In the fifteenth Fe3+ site, Fe3+ is bonded in a hexagonal planar geometry to six O2- atoms. There are a spread of Fe–O bond distances ranging from 1.76–2.04 Å. In the sixteenth Fe3+ site, Fe3+ is bonded in a 8-coordinate geometry to six O2- atoms. There are a spread of Fe–O bond distances ranging from 1.84–2.22 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to four Fe3+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to four Fe3+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to four Fe3+ atoms. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two Fe3+ atoms. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to four Fe3+ atoms. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to three Fe3+ and one O2- atom. The O–O bond length is 2.17 Å. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to three Fe3+ atoms. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to three Fe3+ and one O2- atom. The O–O bond length is 2.32 Å. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to four Fe3+ and one O2- atom. The O–O bond length is 2.30 Å. In the tenth O2- site, O2- is bonded in a 1-coordinate geometry to three Fe3+ and three O2- atoms. There are one shorter (2.12 Å) and one longer (2.21 Å) O–O bond lengths. In the eleventh O2- site, O2- is bonded in a 2-coordinate geometry to three Fe3+ atoms. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to four Fe3+ atoms. In the thirteenth O2- site, O2- is bonded in a 1-coordinate geometry to two Fe3+ and one O2- atom. In the fourteenth O2- site, O2- is bonded in a 2-coordinate geometry to four Fe3+ atoms. In the fifteenth O2- site, O2- is bonded in a 4-coordinate geometry to four Fe3+ atoms. In the sixteenth O2- site, O2- is bonded in a 3-coordinate geometry to three Fe3+ atoms. In the seventeenth O2- site, O2- is bonded in a 3-coordinate geometry to three Fe3+ and one O2- atom. The O–O bond length is 2.36 Å. In the eighteenth O2- site, O2- is bonded in a 1-coordinate geometry to two Fe3+ and one O2- atom. The O–O bond length is 2.15 Å. In the nineteenth O2- site, O2- is bonded in a 2-coordinate geometry to three Fe3+ atoms. In the twentieth O2- site, O2- is bonded in a 1-coordinate geometry to four Fe3+ and three O2- atoms. The O–O bond length is 2.21 Å. In the twenty-first O2- site, O2- is bonded in a 2-coordinate geometry to three Fe3+ and one O2- atom. In the twenty-second O2- site, O2- is bonded in a 1-coordinate geometry to four Fe3+ and three O2- atoms. In the twenty-third O2- site, O2- is bonded in a 4-coordinate geometry to four Fe3+ atoms. In the twenty-fourth O2- site, O2- is bonded in a 4-coordinate geometry to four Fe3+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Fe3O4 by Materials Project

Fe3O4 crystallizes in the triclinic P1 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 six O2- atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 6–16°. There are a spread of Fe–O bond distances ranging from 2.05–2.29 Å. In the second Fe+2.67+ site, Fe+2.67+ 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 7–16°. There are a spread of Fe–O bond distances ranging from 2.06–2.29 Å. In the third Fe+2.67+ site, Fe+2.67+ 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 6–15°. There are a spread of Fe–O bond distances ranging from 2.04–2.07 Å. In the fourth Fe+2.67+ site, Fe+2.67+ 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 6–16°. There are a spread of Fe–O bond distances ranging from 2.04–2.07 Å. In the fifth Fe+2.67+ site, Fe+2.67+ is bonded to six O2- atoms to form edge-sharing FeO6 octahedra. There is two shorter (1.96 Å) and four longer (1.97 Å) Fe–O bond length. In the sixth Fe+2.67+ site, Fe+2.67+ is bonded to six O2- atoms to form edge-sharing FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.95–1.98 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe+2.67+ atoms. In the second O2- site, O2- is bonded to five Fe+2.67+ atoms to form a mixture of edge and corner-sharing OFe5 square pyramids. In the third O2- site, O2- is bonded to five Fe+2.67+ atoms to form a mixture of edge and corner-sharing OFe5 square pyramids. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe+2.67+ atoms. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe+2.67+ atoms. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe+2.67+ atoms. In the seventh O2- site, O2- is bonded to five Fe+2.67+ atoms to form a mixture of edge and corner-sharing OFe5 square pyramids. In the eighth O2- site, O2- is bonded to five Fe+2.67+ atoms to form a mixture of edge and corner-sharing OFe5 square pyramids.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Fe2O3 by Materials Project

Fe2O3 crystallizes in the trigonal P3 space group. The structure is three-dimensional. there are eight inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to four O2- atoms to form distorted FeO4 trigonal pyramids that share corners with two FeO6 octahedra, corners with six equivalent FeO4 trigonal pyramids, and an edgeedge with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 18–49°. There are a spread of Fe–O bond distances ranging from 1.80–2.03 Å. In the second Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with four FeO6 octahedra, corners with six equivalent FeO4 tetrahedra, and an edgeedge with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 20–63°. There are a spread of Fe–O bond distances ranging from 1.91–2.02 Å. In the third Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent FeO4 tetrahedra, edges with six FeO6 octahedra, and a faceface with one FeO6 octahedra. There are three shorter (2.10 Å) and three longer (2.11 Å) Fe–O bond lengths. In the fourth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO6 octahedra, corners with three equivalent FeO4 trigonal pyramids, edges with three equivalent FeO4 trigonal pyramids, and a faceface with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 48–51°. There are three shorter (2.04 Å) and three longer (2.17 Å) Fe–O bond lengths. In the fifth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent FeO4 tetrahedra, edges with three equivalent FeO4 tetrahedra, and a faceface with one FeO6 octahedra. There is three shorter (1.80 Å) and three longer (2.10 Å) Fe–O bond length. In the sixth Fe3+ site, Fe3+ 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 six FeO6 octahedra. The corner-sharing octahedral tilt angles are 48°. There are three shorter (2.05 Å) and three longer (2.10 Å) Fe–O bond lengths. In the seventh Fe3+ site, Fe3+ 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 six FeO6 octahedra. The corner-sharing octahedral tilt angles are 51°. There are three shorter (2.08 Å) and three longer (2.09 Å) Fe–O bond lengths. In the eighth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent FeO4 trigonal pyramids and a faceface with one FeO6 octahedra. There is three shorter (1.85 Å) and three longer (1.97 Å) Fe–O bond length. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a see-saw-like geometry to four Fe3+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Fe3+ atoms. In the third O2- site, O2- is bonded to four Fe3+ atoms to form a mixture of distorted edge and corner-sharing OFe4 trigonal pyramids. In the fourth O2- site, O2- is bonded in an L-shaped geometry to two Fe3+ atoms. In the fifth O2- site, O2- is bonded in a see-saw-like geometry to four Fe3+ atoms. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to two Fe3+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Fe8O9 by Materials Project

Fe8O9 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent Fe+2.25+ sites. In the first Fe+2.25+ site, Fe+2.25+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 0–10°. There are a spread of Fe–O bond distances ranging from 2.15–2.23 Å. In the second Fe+2.25+ site, Fe+2.25+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 0–13°. There are a spread of Fe–O bond distances ranging from 2.13–2.25 Å. In the third Fe+2.25+ site, Fe+2.25+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 4–12°. There are a spread of Fe–O bond distances ranging from 2.06–2.11 Å. In the fourth Fe+2.25+ site, Fe+2.25+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 0–13°. There are a spread of Fe–O bond distances ranging from 2.12–2.26 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to five Fe+2.25+ atoms to form OFe5 square pyramids that share corners with two OFe6 octahedra, corners with seven OFe5 square pyramids, edges with four OFe6 octahedra, and edges with four OFe5 square pyramids. The corner-sharing octahedral tilt angles are 3°. In the second O2- site, O2- is bonded to five Fe+2.25+ atoms to form OFe5 square pyramids that share corners with two equivalent OFe6 octahedra, corners with seven OFe5 square pyramids, edges with five OFe6 octahedra, and edges with three OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 5–9°. In the third O2- site, O2- is bonded to six Fe+2.25+ atoms to form OFe6 octahedra that share a cornercorner with one OFe6 octahedra, corners with five OFe5 square pyramids, edges with four OFe6 octahedra, and edges with eight OFe5 square pyramids. The corner-sharing octahedral tilt angles are 8°. In the fourth O2- site, O2- is bonded to five Fe+2.25+ atoms to form OFe5 square pyramids that share corners with three OFe6 octahedra, corners with six OFe5 square pyramids, edges with three OFe6 octahedra, and edges with five OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 6–10°. In the fifth O2- site, O2- is bonded to six Fe+2.25+ atoms to form OFe6 octahedra that share corners with two equivalent OFe6 octahedra, corners with four OFe5 square pyramids, edges with four equivalent OFe6 octahedra, and edges with eight OFe5 square pyramids. The corner-sharing octahedral tilt angles are 8°.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on FeO by Materials Project

FeO is Molybdenum Carbide MAX Phase-like structured and crystallizes in the hexagonal P-62c space group. The structure is three-dimensional. Fe2+ is bonded to six O2- atoms to form a mixture of edge, corner, and face-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 45–49°. There are a spread of Fe–O bond distances ranging from 2.14–2.29 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to six equivalent Fe2+ atoms to form a mixture of distorted edge and corner-sharing OFe6 pentagonal pyramids. In the second O2- site, O2- is bonded in a 6-coordinate geometry to six equivalent Fe2+ atoms. In the third O2- site, O2- is bonded to six equivalent Fe2+ atoms to form a mixture of distorted edge and corner-sharing OFe6 pentagonal pyramids.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on FeO2 by Materials Project

FeO2 is Rutile structured and crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Fe is bonded to six equivalent O atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There is four shorter (1.94 Å) and two longer (2.02 Å) Fe–O bond length. O is bonded in a trigonal planar geometry to three equivalent Fe atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Fe32O35 by Materials Project

Fe32O35 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are thirty-two inequivalent Fe+2.19+ sites. In the first Fe+2.19+ site, Fe+2.19+ 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 1–18°. There are a spread of Fe–O bond distances ranging from 1.95–2.22 Å. In the second Fe+2.19+ site, Fe+2.19+ 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 2–18°. There are a spread of Fe–O bond distances ranging from 2.04–2.39 Å. In the third Fe+2.19+ site, Fe+2.19+ 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 0–25°. There are a spread of Fe–O bond distances ranging from 2.06–2.37 Å. In the fourth Fe+2.19+ site, Fe+2.19+ 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 1–5°. There are a spread of Fe–O bond distances ranging from 2.03–2.27 Å. In the fifth Fe+2.19+ site, Fe+2.19+ 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 1–5°. There are a spread of Fe–O bond distances ranging from 2.06–2.30 Å. In the sixth Fe+2.19+ site, Fe+2.19+ 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 4–5°. There are a spread of Fe–O bond distances ranging from 1.97–2.15 Å. In the seventh Fe+2.19+ site, Fe+2.19+ 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 2–24°. There are a spread of Fe–O bond distances ranging from 1.98–2.40 Å. In the eighth Fe+2.19+ site, Fe+2.19+ 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 2–12°. There are a spread of Fe–O bond distances ranging from 2.01–2.12 Å. In the ninth Fe+2.19+ site, Fe+2.19+ 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 0–23°. There are a spread of Fe–O bond distances ranging from 2.00–2.40 Å. In the tenth Fe+2.19+ site, Fe+2.19+ 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 4–13°. There are a spread of Fe–O bond distances ranging from 2.11–2.26 Å. In the eleventh Fe+2.19+ site, Fe+2.19+ 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 1–25°. There are a spread of Fe–O bond distances ranging from 2.07–2.27 Å. In the twelfth Fe+2.19+ site, Fe+2.19+ 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 3–9°. There are a spread of Fe–O bond distances ranging from 2.00–2.35 Å. In the thirteenth Fe+2.19+ site, Fe+2.19+ 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 a spread of Fe–O bond distances ranging from 2.02–2.27 Å. In the fourteenth Fe+2.19+ site, Fe+2.19+ 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 1–13°. There are a spread of Fe–O bond distances ranging from 2.08–2.22 Å. In the fifteenth Fe+2.19+ site, Fe+2.19+ 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 6–11°. There are a spread of Fe–O bond distances ranging from 2.14–2.26 Å. In the sixteenth Fe+2.19+ site, Fe+2.19+ 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 1–24°. There are a spread of Fe–O bond distances ranging from 2.01–2.36 Å. In the seventeenth Fe+2.19+ site, Fe+2.19+ 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 1–23°. There are a spread of Fe–O bond distances ranging from 2.02–2.33 Å. In the eighteenth Fe+2.19+ site, Fe+2.19+ 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 2–9°. There are a spread of Fe–O bond distances ranging from 2.07–2.30 Å. In the nineteenth Fe+2.19+ site, Fe+2.19+ 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 5–6°. There are a spread of Fe–O bond distances ranging from 2.15–2.27 Å. In the twentieth Fe+2.19+ site, Fe+2.19+ 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 3–7°. There are a spread of Fe–O bond distances ranging from 2.05–2.33 Å. In the twenty-first Fe+2.19+ site, Fe+2.19+ 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 3–5°. There are a spread of Fe–O bond distances ranging from 1.97–2.13 Å. In the twenty-second Fe+2.19+ site, Fe+2.19+ 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 5–7°. There are a spread of Fe–O bond distances ranging from 2.13–2.24 Å. In the twenty-third Fe+2.19+ site, Fe+2.19+ 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 3–9°. There are a spread of Fe–O bond distances ranging from 2.11–2.24 Å. In the twenty-fourth Fe+2.19+ site, Fe+2.19+ 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 1–19°. There are a spread of Fe–O bond distances ranging from 2.07–2.35 Å. In the twenty-fifth Fe+2.19+ site, Fe+2.19+ 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 1–25°. There are a spread of Fe–O bond distances ranging from 2.08–2.28 Å. In the twenty-sixth Fe+2.19+ site, Fe+2.19+ 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 3–25°. There are a spread of Fe–O bond distances ranging from 2.08–2.34 Å. In the twenty-seventh Fe+2.19+ site, Fe+2.19+ 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 1–7°. There are a spread of Fe–O bond distances ranging from 2.09–2.28 Å. In the twenty-eighth Fe+2.19+ site, Fe+2.19+ 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 2–7°. There are a spread of Fe–O bond distances ranging from 2.04–2.30 Å. In the twenty-ninth Fe+2.19+ site, Fe+2.19+ 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 2–5°. There are a spread of Fe–O bond distances ranging from 2.00–2.17 Å. In the thirtieth Fe+2.19+ site, Fe+2.19+ 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 3–6°. There are a spread of Fe–O bond distances ranging from 2.13–2.33 Å. In the thirty-first Fe+2.19+ site, Fe+2.19+ 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 1–7°. There are a spread of Fe–O bond distances ranging from 2.13–2.26 Å. In the thirty-second Fe+2.19+ site, Fe+2.19+ 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 4–19°. There are a spread of Fe–O bond distances ranging from 1.96–2.24 Å. There are thirty-five inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe+2.19+ atoms. In the second O2- site, O2- is bonded to six Fe+2.19+ atoms to form OFe6 octahedra that share corners with four OFe6 octahedra, corners with two equivalent OFe5 square pyramids, edges with nine OFe6 octahedra, and an edgeedge with one OFe5 square pyramid. The corner-sharing octahedra tilt angles range from 2–9°. In the third O2- site, O2- is bonded to five Fe+2.19+ atoms to form OFe5 square pyramids that share corners with four OFe6 octahedra, a cornercorner with one OFe5 square pyramid, corners with two equivalent OFe4 trigonal pyramids, edges with six OFe6 octahedra, and edges with two equivalent OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 11–17°. In the fourth O2- site, O2- is bonded to six Fe+2.19+ atoms to form OFe6 octahedra that share corners with four OFe6 octahedra, corners with two equivalent OFe5 square pyramids, edges with nine OFe6 octahedra, an edgeedge with one OFe5 square pyramid, and edges with two equivalent OFe4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 2–6°. In the fifth O2- site, O2- is bonded to six Fe+2.19+ atoms to form OFe6 octahedra that share corners with four OFe6 octahedra, a cornercorner with one OFe4 trigonal pyramid, edges with eight OFe6 octahedra, and edges with four OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 1–4°. In the sixth O2- site, O2- is bonded to six Fe+2.19+ atoms to form OFe6 octahedra that share corners with four OFe6 octahedra, corners with two OFe4 trigonal pyramids, edges with eight OFe6 octahedra, and edges with four OFe5 square pyramids. The corner-sharing octahedral tilt angles are 1°. In the seventh O2- site, O2- is bonded to four Fe+2.19+ atoms to form distorted OFe4 trigonal pyramids that share corners with four OFe6 octahedra, corners with four OFe5 square pyramids, corners with two equivalent OFe4 trigonal pyramids, and edges with five OFe6 octahedra. The corner-sharing octahedra tilt angles range from 3–14°. In the eighth O2- site, O2- is bonded to six Fe+2.19+ atoms to form OFe6 octahedra that share corners with two OFe6 octahedra, corners with two equivalent OFe5 square pyramids, corners with two equivalent OFe4 trigonal pyramids, edges with eight OFe6 octahedra, an edgeedge with one OFe5 square pyramid, and edges with three OFe4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 1–5°. In the ninth O2- site, O2- is bonded to five Fe+2.19+ atoms to form OFe5 square pyramids that share corners with four OFe6 octahedra, a cornercorner with one OFe5 square pyramid, corners with four OFe4 trigonal pyramids, edges with six OFe6 octahedra, and edges with two equivalent OFe5 square pyramids. The corner-sharing octahedra tilt angles range from 17–19°. In the tenth O2- site, O2- is bonded to six Fe+2.19+ atoms to form OFe6 octahedra that share corners with four OFe6 octahedra, corners with two equivalent OFe5 square pyramids, edges with nine OFe6 octahedra, an edgeedge with one OFe5 square pyramid, and edges with two equivalent OFe4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 2–6°. In the eleventh O2- site, O2- is bonded to six Fe+2.19+ atoms to form OFe6 octahedra that share corners with two OFe6 octahedra, corners with two equivalent OFe5 square pyramids, corners with two equivalent OFe4 trigonal pyramids, edges with eight OFe6 octahedra, an edgeedge with one OFe5 square pyramid, and edges with three OFe4 trigonal pyramids. The corner-sharing oc

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on FeO2 by Materials Project

FeO2 is Cyanogen Chloride-derived structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is zero-dimensional and consists of two iron dihydroxide molecules. Fe is bonded in a linear geometry to two equivalent O atoms. Both Fe–O bond lengths are 1.59 Å. O is bonded in a single-bond geometry to one Fe atom.

36 MATERIALS SCIENCE↗