DOI: 10.17188/1738837
title: Materials Data on Ba9(FeSe4)4 by Materials Project

description: Ba9Fe4Se16 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are ten inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.31–3.50 Å. In the second Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.32–3.46 Å. In the third Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to seven Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.16–3.57 Å. In the fourth Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.29–3.91 Å. In the fifth Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to seven Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.17–3.75 Å. In the sixth Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.26–3.90 Å. In the seventh Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to seven Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.13–3.70 Å. In the eighth Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to nine Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.12–3.97 Å. In the ninth Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to seven Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.13–3.72 Å. In the tenth Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to nine Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.15–3.94 Å. There are four inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to four Se+1.62- atoms to form edge-sharing FeSe4 tetrahedra. There are a spread of Fe–Se bond distances ranging from 2.38–2.41 Å. In the second Fe2+ site, Fe2+ is bonded to four Se+1.62- atoms to form edge-sharing FeSe4 tetrahedra. There are a spread of Fe–Se bond distances ranging from 2.39–2.42 Å. In the third Fe2+ site, Fe2+ is bonded to four Se+1.62- atoms to form edge-sharing FeSe4 tetrahedra. There are a spread of Fe–Se bond distances ranging from 2.38–2.41 Å. In the fourth Fe2+ site, Fe2+ is bonded to four Se+1.62- atoms to form edge-sharing FeSe4 tetrahedra. There are a spread of Fe–Se bond distances ranging from 2.38–2.41 Å. There are seventeen inequivalent Se+1.62- sites. In the first Se+1.62- site, Se+1.62- is bonded to five Ba2+ and one Fe2+ atom to form a mixture of distorted corner, edge, and face-sharing SeBa5Fe octahedra. The corner-sharing octahedra tilt angles range from 48–50°. In the second Se+1.62- site, Se+1.62- is bonded to five Ba2+ and one Fe2+ atom to form a mixture of distorted corner, edge, and face-sharing SeBa5Fe octahedra. The corner-sharing octahedra tilt angles range from 46–53°. In the third Se+1.62- site, Se+1.62- is bonded to five Ba2+ and one Fe2+ atom to form a mixture of distorted corner, edge, and face-sharing SeBa5Fe octahedra. The corner-sharing octahedra tilt angles range from 46–50°. In the fourth Se+1.62- site, Se+1.62- is bonded to five Ba2+ and one Fe2+ atom to form a mixture of distorted corner, edge, and face-sharing SeBa5Fe octahedra. The corner-sharing octahedra tilt angles range from 48–53°. In the fifth Se+1.62- site, Se+1.62- is bonded in a 6-coordinate geometry to five Ba2+ and one Fe2+ atom. In the sixth Se+1.62- site, Se+1.62- is bonded in a 6-coordinate geometry to five Ba2+ and one Fe2+ atom. In the seventh Se+1.62- site, Se+1.62- is bonded in a 6-coordinate geometry to five Ba2+ and one Fe2+ atom. In the eighth Se+1.62- site, Se+1.62- is bonded in a 6-coordinate geometry to five Ba2+ and one Fe2+ atom. In the ninth Se+1.62- site, Se+1.62- is bonded in a 5-coordinate geometry to four Ba2+, two equivalent Fe2+, and one Se+1.62- atom. The Se–Se bond length is 3.54 Å. In the tenth Se+1.62- site, Se+1.62- is bonded in a 5-coordinate geometry to three Ba2+ and two equivalent Fe2+ atoms. In the eleventh Se+1.62- site, Se+1.62- is bonded in a 5-coordinate geometry to four Ba2+, two equivalent Fe2+, and one Se+1.62- atom. The Se–Se bond length is 3.56 Å. In the twelfth Se+1.62- site, Se+1.62- is bonded in a 5-coordinate geometry to three Ba2+ and two equivalent Fe2+ atoms. In the thirteenth Se+1.62- site, Se+1.62- is bonded in a 4-coordinate geometry to four Ba2+ atoms. In the fourteenth Se+1.62- site, Se+1.62- is bonded in a 4-coordinate geometry to four Ba2+ atoms. In the fifteenth Se+1.62- site, Se+1.62- is bonded in a 4-coordinate geometry to five Ba2+ and three Se+1.62- atoms. There are one shorter (2.41 Å) and one longer (2.95 Å) Se–Se bond lengths. In the sixteenth Se+1.62- site, Se+1.62- is bonded in a square co-planar geometry to four Ba2+ atoms. In the seventeenth Se+1.62- site, Se+1.62- is bonded in a 4-coordinate geometry to five Ba2+ and three Se+1.62- atoms. The Se–Se bond length is 2.93 Å.