Materials Data on Fe7Se8 by Materials Project
Fe7Se8 crystallizes in the trigonal P3_121 space group. The structure is three-dimensional. there are five inequivalent Fe+2.29+ sites. In the first Fe+2.29+ site, Fe+2.29+ is bonded to six Se2- atoms to form a mixture of corner, edge, and face-sharing FeSe6 octahedra. The corner-sharing octahedra tilt angles range from 48–54°. There are a spread of Fe–Se bond distances ranging from 2.49–2.60 Å. In the second Fe+2.29+ site, Fe+2.29+ is bonded to six Se2- atoms to form a mixture of corner, edge, and face-sharing FeSe6 octahedra. The corner-sharing octahedra tilt angles range from 47–58°. There are a spread of Fe–Se bond distances ranging from 2.43–2.58 Å. In the third Fe+2.29+ site, Fe+2.29+ is bonded to six Se2- atoms to form a mixture of corner, edge, and face-sharing FeSe6 octahedra. The corner-sharing octahedra tilt angles range from 51–58°. There are a spread of Fe–Se bond distances ranging from 2.44–2.61 Å. In the fourth Fe+2.29+ site, Fe+2.29+ is bonded to six Se2- atoms to form a mixture of corner, edge, and face-sharing FeSe6 octahedra. The corner-sharing octahedra tilt angles range from 51–56°. There are a spread of Fe–Se bond distances ranging from 2.36–2.54 Å. In the fifth Fe+2.29+ site, Fe+2.29+ is bonded to six Se2- atoms to form a mixture of corner, edge, and face-sharing FeSe6 octahedra. The corner-sharing octahedra tilt angles range from 47–53°. There are a spread of Fe–Se bond distances ranging from 2.42–2.54 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to five Fe+2.29+ atoms. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to five Fe+2.29+ atoms. In the third Se2- site, Se2- is bonded in a 6-coordinate geometry to six Fe+2.29+ atoms. In the fourth Se2- site, Se2- is bonded in a 5-coordinate geometry to five Fe+2.29+ atoms.