DOE OSTI2020
Gd(Fe5Si)2 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Gd is bonded in a 12-coordinate geometry to sixteen Fe and four equivalent Si atoms. There are a spread of Gd–Fe bond distances ranging from 2.95–3.18 Å. All Gd–Si bond lengths are 3.09 Å. There are four inequivalent Fe sites. In the first Fe site, Fe is bonded in a 10-coordinate geometry to one Gd, eleven Fe, and two equivalent Si atoms. There are a spread of Fe–Fe bond distances ranging from 2.32–2.90 Å. Both Fe–Si bond lengths are 2.59 Å. In the second Fe site, Fe is bonded in a 10-coordinate geometry to one Gd, eleven Fe, and two equivalent Si atoms. There are a spread of Fe–Fe bond distances ranging from 2.41–2.65 Å. Both Fe–Si bond lengths are 2.51 Å. In the third Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent Gd, eight Fe, and two equivalent Si atoms. All Fe–Fe bond lengths are 2.43 Å. Both Fe–Si bond lengths are 2.65 Å. In the fourth Fe site, Fe is bonded to two equivalent Gd, eight Fe, and two equivalent Si atoms to form distorted FeGd2Fe8Si2 cuboctahedra that share corners with four equivalent SiGd2Fe10 cuboctahedra, corners with ten equivalent FeGd2Fe8Si2 cuboctahedra, edges with two equivalent SiGd2Fe10 cuboctahedra, edges with four equivalent FeGd2Fe8Si2 cuboctahedra, faces with four equivalent SiGd2Fe10 cuboctahedra, and faces with six equivalent FeGd2Fe8Si2 cuboctahedra. Both Fe–Fe bond lengths are 2.37 Å. Both Fe–Si bond lengths are 2.39 Å. Si is bonded to two equivalent Gd and ten Fe atoms to form distorted SiGd2Fe10 cuboctahedra that share corners with six equivalent SiGd2Fe10 cuboctahedra, corners with eight equivalent FeGd2Fe8Si2 cuboctahedra, edges with three equivalent SiGd2Fe10 cuboctahedra, edges with four equivalent FeGd2Fe8Si2 cuboctahedra, a faceface with one SiGd2Fe10 cuboctahedra, and faces with eight equivalent FeGd2Fe8Si2 cuboctahedra.