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Title: Materials Data on K9Fe2Se7 by Materials Project

Abstract

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 threemore » 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.« less

Authors:
Publication Date:
Other Number(s):
mp-21960
DOE Contract Number:  
AC02-05CH11231; EDCBEE
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). LBNL Materials Project
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Collaborations:
MIT; UC Berkeley; Duke; U Louvain
Subject:
36 MATERIALS SCIENCE
Keywords:
crystal structure; K9Fe2Se7; Fe-K-Se
OSTI Identifier:
1197267
DOI:
https://doi.org/10.17188/1197267

Citation Formats

The Materials Project. Materials Data on K9Fe2Se7 by Materials Project. United States: N. p., 2020. Web. doi:10.17188/1197267.
The Materials Project. Materials Data on K9Fe2Se7 by Materials Project. United States. doi:https://doi.org/10.17188/1197267
The Materials Project. 2020. "Materials Data on K9Fe2Se7 by Materials Project". United States. doi:https://doi.org/10.17188/1197267. https://www.osti.gov/servlets/purl/1197267. Pub date:Wed Apr 29 00:00:00 EDT 2020
@article{osti_1197267,
title = {Materials Data on K9Fe2Se7 by Materials Project},
author = {The Materials Project},
abstractNote = {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.},
doi = {10.17188/1197267},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2020},
month = {4}
}