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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ta6Fe16Si7 by Materials Project

Fe16Ta6Si7 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ta is bonded in a 12-coordinate geometry to eight Fe and four equivalent Si atoms. There are four shorter (2.74 Å) and four longer (2.77 Å) Ta–Fe bond lengths. All Ta–Si bond lengths are 2.85 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded in a 1-coordinate geometry to three equivalent Ta, six Fe, and four Si atoms. There are three shorter (2.47 Å) and three longer (2.68 Å) Fe–Fe bond lengths. There are one shorter (2.32 Å) and three longer (2.46 Å) Fe–Si bond lengths. In the second Fe site, Fe is bonded in a 12-coordinate geometry to three equivalent Ta, six Fe, and three equivalent Si atoms. All Fe–Fe bond lengths are 2.43 Å. All Fe–Si bond lengths are 2.29 Å. There are two inequivalent Si sites. In the first Si site, Si is bonded to four equivalent Ta and eight Fe atoms to form a mixture of corner and face-sharing SiTa4Fe8 cuboctahedra. In the second Si site, Si is bonded in a body-centered cubic geometry to eight equivalent Fe atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta3Fe8Si by Materials Project

Ta3Fe8Si is Hexagonal Laves-derived structured and crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. there are three inequivalent Ta sites. In the first Ta site, Ta is bonded in a 12-coordinate geometry to one Ta, twelve Fe, and three equivalent Si atoms. The Ta–Ta bond length is 2.92 Å. There are a spread of Ta–Fe bond distances ranging from 2.75–2.80 Å. All Ta–Si bond lengths are 2.89 Å. In the second Ta site, Ta is bonded in a 12-coordinate geometry to four Ta and twelve Fe atoms. All Ta–Ta bond lengths are 2.98 Å. There are nine shorter (2.79 Å) and three longer (2.81 Å) Ta–Fe bond lengths. In the third Ta site, Ta is bonded in a 10-coordinate geometry to three equivalent Ta, twelve Fe, and one Si atom. There are a spread of Ta–Fe bond distances ranging from 2.72–2.94 Å. The Ta–Si bond length is 2.80 Å. There are four inequivalent Fe sites. In the first Fe site, Fe is bonded to three equivalent Ta, six Fe, and three equivalent Si atoms to form FeTa3Fe6Si3 cuboctahedra that share corners with twelve FeTa4Fe6Si2 cuboctahedra, edges with six equivalent FeTa3Fe6Si3 cuboctahedra, and faces with twenty FeTa6Fe6 cuboctahedra. There are three shorter (2.37 Å) and three longer (2.39 Å) Fe–Fe bond lengths. All Fe–Si bond lengths are 2.78 Å. In the second Fe site, Fe is bonded to six Ta and six Fe atoms to form FeTa6Fe6 cuboctahedra that share corners with twelve FeTa4Fe6Si2 cuboctahedra, edges with six equivalent FeTa6Fe6 cuboctahedra, and faces with twenty FeTa3Fe6Si3 cuboctahedra. There are three shorter (2.37 Å) and three longer (2.44 Å) Fe–Fe bond lengths. In the third Fe site, Fe is bonded to four Ta, six Fe, and two equivalent Si atoms to form FeTa4Fe6Si2 cuboctahedra that share corners with eighteen FeTa3Fe6Si3 cuboctahedra, edges with six FeTa5Fe6Si cuboctahedra, and faces with eighteen FeTa3Fe6Si3 cuboctahedra. There are two shorter (2.35 Å) and two longer (2.41 Å) Fe–Fe bond lengths. Both Fe–Si bond lengths are 2.81 Å. In the fourth Fe site, Fe is bonded to five Ta, six Fe, and one Si atom to form FeTa5Fe6Si cuboctahedra that share corners with eighteen FeTa3Fe6Si3 cuboctahedra, edges with six FeTa5Fe6Si cuboctahedra, and faces with eighteen FeTa3Fe6Si3 cuboctahedra. There are two shorter (2.33 Å) and two longer (2.43 Å) Fe–Fe bond lengths. The Fe–Si bond length is 2.72 Å. Si is bonded in a 4-coordinate geometry to four Ta and twelve Fe atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaFe4Si by Materials Project

TaFe4Si crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Ta is bonded in a 1-coordinate geometry to twelve Fe and one Si atom. There are a spread of Ta–Fe bond distances ranging from 2.74–2.86 Å. The Ta–Si bond length is 2.73 Å. There are three inequivalent Fe sites. In the first Fe site, Fe is bonded to six equivalent Fe and six equivalent Si atoms to form FeFe6Si6 cuboctahedra that share corners with twelve equivalent FeTa3Fe6Si3 cuboctahedra, edges with six equivalent FeFe6Si6 cuboctahedra, and faces with twenty FeTa6Fe6 cuboctahedra. All Fe–Fe bond lengths are 2.32 Å. All Fe–Si bond lengths are 2.80 Å. In the second Fe site, Fe is bonded to six equivalent Ta and six equivalent Fe atoms to form FeTa6Fe6 cuboctahedra that share corners with twelve equivalent FeTa3Fe6Si3 cuboctahedra, edges with six equivalent FeTa6Fe6 cuboctahedra, and faces with twenty FeFe6Si6 cuboctahedra. All Fe–Fe bond lengths are 2.39 Å. In the third Fe site, Fe is bonded to three equivalent Ta, six Fe, and three equivalent Si atoms to form FeTa3Fe6Si3 cuboctahedra that share corners with eighteen FeFe6Si6 cuboctahedra, edges with six equivalent FeTa3Fe6Si3 cuboctahedra, and faces with eighteen FeFe6Si6 cuboctahedra. There are two shorter (2.34 Å) and two longer (2.45 Å) Fe–Fe bond lengths. There are one shorter (2.64 Å) and two longer (2.77 Å) Fe–Si bond lengths. Si is bonded in a 1-coordinate geometry to one Ta and twelve Fe atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta4Fe4Si7 by Materials Project

Ta4Fe4Si7 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Ta3+ sites. In the first Ta3+ site, Ta3+ is bonded to seven Si+2.86- atoms to form a mixture of face, edge, and corner-sharing TaSi7 pentagonal bipyramids. There are a spread of Ta–Si bond distances ranging from 2.66–2.83 Å. In the second Ta3+ site, Ta3+ is bonded to seven Si+2.86- atoms to form a mixture of face, edge, and corner-sharing TaSi7 pentagonal bipyramids. There are a spread of Ta–Si bond distances ranging from 2.63–2.83 Å. Fe2+ is bonded in a 6-coordinate geometry to six Si+2.86- atoms. There are a spread of Fe–Si bond distances ranging from 2.29–2.37 Å. There are four inequivalent Si+2.86- sites. In the first Si+2.86- site, Si+2.86- is bonded in a 9-coordinate geometry to five Ta3+ and four equivalent Fe2+ atoms. In the second Si+2.86- site, Si+2.86- is bonded in a 12-coordinate geometry to four Ta3+ and four equivalent Fe2+ atoms. In the third Si+2.86- site, Si+2.86- is bonded in a 6-coordinate geometry to one Ta3+, four equivalent Fe2+, and one Si+2.86- atom. The Si–Si bond length is 2.36 Å. In the fourth Si+2.86- site, Si+2.86- is bonded in a 10-coordinate geometry to eight Ta3+ and two equivalent Si+2.86- atoms. There are one shorter (2.50 Å) and one longer (2.51 Å) Si–Si bond lengths.

36 MATERIALS SCIENCE↗