Materials Data on K9Fe2Se7 by Materials Project

Dataset · Wed Apr 29 04:00:00 EDT 2020

DOI:https://doi.org/10.17188/1197267· OSTI ID:1197267

K9Fe2Se7 crystallizes in the cubic P2_13 space group. The structure is three-dimensional. there are five inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to five Se2- atoms to form distorted KSe5 trigonal bipyramids that share a cornercorner with one KSe6 octahedra, a cornercorner with one FeSe4 tetrahedra, corners with six equivalent KSe5 trigonal bipyramids, an edgeedge with one FeSe4 tetrahedra, and a faceface with one KSe6 octahedra. The corner-sharing octahedral tilt angles are 38°. There are a spread of K–Se bond distances ranging from 3.19–3.43 Å. In the second K1+ site, K1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are three shorter (3.36 Å) and three longer (3.53 Å) K–Se bond lengths. In the third K1+ site, K1+ is bonded in a 5-coordinate geometry to five Se2- atoms. There are a spread of K–Se bond distances ranging from 3.45–3.57 Å. In the fourth K1+ site, K1+ is bonded in a distorted T-shaped geometry to three equivalent Se2- atoms. All K–Se bond lengths are 3.31 Å. In the fifth K1+ site, K1+ is bonded to six Se2- atoms to form distorted KSe6 octahedra that share corners with three equivalent FeSe4 tetrahedra, corners with three equivalent KSe5 trigonal bipyramids, and faces with three equivalent KSe5 trigonal bipyramids. There are three shorter (3.35 Å) and three longer (3.55 Å) K–Se bond lengths. There are two inequivalent Fe+2.50+ sites. In the first Fe+2.50+ site, Fe+2.50+ is bonded in a trigonal planar geometry to three equivalent Se2- atoms. All Fe–Se bond lengths are 2.36 Å. In the second Fe+2.50+ site, Fe+2.50+ is bonded to four Se2- atoms to form FeSe4 tetrahedra that share corners with three equivalent KSe6 octahedra, corners with three equivalent KSe5 trigonal bipyramids, and edges with three equivalent KSe5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 45°. There are three shorter (2.43 Å) and one longer (2.49 Å) Fe–Se bond lengths. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 7-coordinate geometry to six K1+ and one Fe+2.50+ atom. In the second Se2- site, Se2- is bonded in a 1-coordinate geometry to seven K1+ and one Fe+2.50+ atom. In the third Se2- site, Se2- is bonded in a 1-coordinate geometry to six K1+ and one Fe+2.50+ atom.

• Research Organization: LBNL Materials Project; Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Contributing Organization: The Materials Project; MIT; UC Berkeley; Duke; U Louvain
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 1197267
• Report Number(s): mp-21960
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Fe-K-Se
K9Fe2Se7
crystal structure