Materials Data on Sm(Fe5Si)2 by Materials Project

Sm(Fe5Si)2 crystallizes in the orthorhombic Fmmm space group. The structure is three-dimensional. Sm is bonded in a 12-coordinate geometry to sixteen Fe and four equivalent Si atoms. There are a spread of Sm–Fe bond distances ranging from 2.99–3.19 Å. All Sm–Si bond lengths are 3.15 Å. There are three inequivalent Fe sites. In the first Fe site, Fe is bonded in a 10-coordinate geometry to one Sm, eleven Fe, and two equivalent Si atoms. There are a spread of Fe–Fe bond distances ranging from 2.33–2.94 Å. Both Fe–Si bond lengths are 2.55 Å. In the second Fe site, Fe is bonded to two equivalent Sm and ten Fe atoms to form FeSm2Fe10 cuboctahedra that share corners with four equivalent SiSm2Fe8Si2 cuboctahedra, corners with fourteen FeSm2Fe10 cuboctahedra, edges with four equivalent FeSm2Fe8Si2 cuboctahedra, edges with four equivalent SiSm2Fe8Si2 cuboctahedra, faces with four equivalent SiSm2Fe8Si2 cuboctahedra, and faces with ten FeSm2Fe10 cuboctahedra. There are two shorter (2.40 Å) and four longer (2.41 Å) Fe–Fe bond lengths. In the third Fe site, Fe is bonded to two equivalent Sm, eight Fe, and two equivalent Si atoms to form distorted FeSm2Fe8Si2 cuboctahedra that share corners with four equivalent SiSm2Fe8Si2 cuboctahedra, corners with fourteen FeSm2Fe10 cuboctahedra, edges with two equivalent SiSm2Fe8Si2 cuboctahedra, edges with five FeSm2Fe10 cuboctahedra, faces with four equivalent SiSm2Fe8Si2 cuboctahedra, and faces with eleven FeSm2Fe10 cuboctahedra. There are one shorter (2.65 Å) and one longer (2.66 Å) Fe–Fe bond lengths. Both Fe–Si bond lengths are 2.40 Å. Si is bonded to two equivalent Sm, eight Fe, and two equivalent Si atoms to form distorted SiSm2Fe8Si2 cuboctahedra that share corners with six equivalent SiSm2Fe8Si2 cuboctahedra, corners with twelve FeSm2Fe10 cuboctahedra, edges with eight FeSm2Fe10 cuboctahedra, faces with two equivalent SiSm2Fe8Si2 cuboctahedra, and faces with twelve FeSm2Fe10 cuboctahedra. Both Si–Si bond lengths are 2.40 Å.