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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on La(FeSi)2 by Materials Project

LaFe2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. La3+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All La–Si bond lengths are 3.21 Å. Fe+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of distorted edge and corner-sharing FeSi4 tetrahedra. All Fe–Si bond lengths are 2.28 Å. Si4- is bonded in a 4-coordinate geometry to four equivalent La3+ and four equivalent Fe+2.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LaFeSi by Materials Project

LaFeSi is Matlockite structured and crystallizes in the tetragonal P4/nmm space group. The structure is two-dimensional and consists of one LaFeSi sheet oriented in the (0, 0, 1) direction. La2+ is bonded in a 4-coordinate geometry to four equivalent Si4- atoms. All La–Si bond lengths are 3.10 Å. Fe2+ is bonded to four equivalent Si4- atoms to form a mixture of edge and corner-sharing FeSi4 tetrahedra. All Fe–Si bond lengths are 2.33 Å. Si4- is bonded in a 10-coordinate geometry to four equivalent La2+ and four equivalent Fe2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LaFe9Si4 by Materials Project

LaFe9Si4 crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. La is bonded in a 8-coordinate geometry to sixteen Fe and eight equivalent Si atoms. There are eight shorter (3.25 Å) and eight longer (3.34 Å) La–Fe bond lengths. All La–Si bond lengths are 3.28 Å. There are three inequivalent Fe sites. In the first Fe site, Fe is bonded to two equivalent La, six Fe, and four equivalent Si atoms to form a mixture of distorted face and corner-sharing FeLa2Fe6Si4 cuboctahedra. There are a spread of Fe–Fe bond distances ranging from 2.36–2.61 Å. There are two shorter (2.49 Å) and two longer (2.54 Å) Fe–Si bond lengths. In the second Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent La, six Fe, and four equivalent Si atoms. There are a spread of Fe–Fe bond distances ranging from 2.47–2.66 Å. There are a spread of Fe–Si bond distances ranging from 2.39–2.47 Å. In the third Fe site, Fe is bonded to eight Fe and four equivalent Si atoms to form a mixture of face and corner-sharing FeFe8Si4 cuboctahedra. All Fe–Si bond lengths are 2.41 Å. Si is bonded in a 12-coordinate geometry to two equivalent La, nine Fe, and one Si atom. The Si–Si bond length is 2.79 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LaFeSi2 by Materials Project

LaFeSi2 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. La is bonded in a 4-coordinate geometry to four equivalent Fe and ten Si atoms. There are two shorter (3.17 Å) and two longer (3.20 Å) La–Fe bond lengths. There are a spread of La–Si bond distances ranging from 3.14–3.24 Å. Fe is bonded in a 4-coordinate geometry to four equivalent La and four equivalent Si atoms. There are two shorter (2.27 Å) and two longer (2.32 Å) Fe–Si bond lengths. There are two inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to four equivalent La, four equivalent Fe, and one Si atom. The Si–Si bond length is 2.61 Å. In the second Si site, Si is bonded in a 9-coordinate geometry to six equivalent La and three Si atoms. Both Si–Si bond lengths are 2.40 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LaFe8Si5 by Materials Project

LaFe8Si5 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. La3+ is bonded in a 10-coordinate geometry to ten Si4- atoms. There are a spread of La–Si bond distances ranging from 3.19–3.36 Å. There are seven inequivalent Fe+2.12+ sites. In the first Fe+2.12+ site, Fe+2.12+ is bonded to one Fe+2.12+ and four Si4- atoms to form distorted FeFeSi4 tetrahedra that share corners with two equivalent FeFe6Si6 cuboctahedra, corners with two equivalent FeFeSi4 tetrahedra, an edgeedge with one FeFe8Si4 cuboctahedra, an edgeedge with one FeFeSi4 tetrahedra, and a faceface with one FeFeSi4 tetrahedra. The Fe–Fe bond length is 2.48 Å. There are a spread of Fe–Si bond distances ranging from 2.34–2.40 Å. In the second Fe+2.12+ site, Fe+2.12+ is bonded in a 5-coordinate geometry to two Fe+2.12+ and five Si4- atoms. There are one shorter (2.49 Å) and one longer (2.51 Å) Fe–Fe bond lengths. There are a spread of Fe–Si bond distances ranging from 2.35–2.46 Å. In the third Fe+2.12+ site, Fe+2.12+ is bonded to six Fe+2.12+ and six Si4- atoms to form distorted corner-sharing FeFe6Si6 cuboctahedra. Both Fe–Fe bond lengths are 2.41 Å. There are two shorter (2.33 Å) and four longer (2.38 Å) Fe–Si bond lengths. In the fourth Fe+2.12+ site, Fe+2.12+ is bonded to eight Fe+2.12+ and four equivalent Si4- atoms to form distorted edge-sharing FeFe8Si4 cuboctahedra. There are two shorter (2.41 Å) and two longer (2.47 Å) Fe–Fe bond lengths. All Fe–Si bond lengths are 2.35 Å. In the fifth Fe+2.12+ site, Fe+2.12+ is bonded in a 9-coordinate geometry to three Fe+2.12+ and four Si4- atoms. There are one shorter (2.33 Å) and one longer (2.34 Å) Fe–Fe bond lengths. There are two shorter (2.47 Å) and two longer (2.53 Å) Fe–Si bond lengths. In the sixth Fe+2.12+ site, Fe+2.12+ is bonded in a 2-coordinate geometry to one Fe+2.12+ and six Si4- atoms. There are a spread of Fe–Si bond distances ranging from 2.31–2.60 Å. In the seventh Fe+2.12+ site, Fe+2.12+ is bonded in a 10-coordinate geometry to five Fe+2.12+ and five Si4- atoms. There are three shorter (2.51 Å) and two longer (2.53 Å) Fe–Si bond lengths. There are three inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 11-coordinate geometry to two equivalent La3+, eight Fe+2.12+, and one Si4- atom. The Si–Si bond length is 2.59 Å. In the second Si4- site, Si4- is bonded in a 11-coordinate geometry to two equivalent La3+, eight Fe+2.12+, and one Si4- atom. The Si–Si bond length is 2.58 Å. In the third Si4- site, Si4- is bonded in a 12-coordinate geometry to two equivalent La3+, six Fe+2.12+, and four Si4- atoms.

36 MATERIALS SCIENCE↗