Materials Data on Sm2Cr(Fe8C)2 by Materials Project

Sm2Cr(Fe8C)2 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are two inequivalent Sm sites. In the first Sm site, Sm is bonded in a distorted bent 120 degrees geometry to eight Fe and two equivalent C atoms. There are a spread of Sm–Fe bond distances ranging from 3.06–3.40 Å. Both Sm–C bond lengths are 2.53 Å. In the second Sm site, Sm is bonded in a distorted bent 120 degrees geometry to one Cr, eight Fe, and two equivalent C atoms. The Sm–Cr bond length is 3.22 Å. There are a spread of Sm–Fe bond distances ranging from 3.02–3.44 Å. Both Sm–C bond lengths are 2.54 Å. Cr is bonded in a 1-coordinate geometry to one Sm and thirteen Fe atoms. There are a spread of Cr–Fe bond distances ranging from 2.31–2.74 Å. There are ten inequivalent Fe sites. In the first Fe site, Fe is bonded to three Sm, one Cr, and eight Fe atoms to form distorted FeSm3CrFe8 cuboctahedra that share corners with eleven FeSm3CrFe8 cuboctahedra, corners with four equivalent CSm2Fe4 octahedra, edges with four FeSm3Fe9 cuboctahedra, faces with eight FeSm3Fe9 cuboctahedra, and faces with two equivalent CSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 63–71°. There are a spread of Fe–Fe bond distances ranging from 2.45–2.69 Å. In the second Fe site, Fe is bonded in a single-bond geometry to one Cr, four Fe, and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.45–2.58 Å. The Fe–C bond length is 1.92 Å. In the third Fe site, Fe is bonded to three Sm and nine Fe atoms to form distorted FeSm3Fe9 cuboctahedra that share corners with eleven FeSm3CrFe8 cuboctahedra, corners with four equivalent CSm2Fe4 octahedra, edges with four FeSm3CrFe8 cuboctahedra, faces with eight FeSm3CrFe8 cuboctahedra, and faces with two equivalent CSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 62–69°. There are a spread of Fe–Fe bond distances ranging from 2.47–2.68 Å. In the fourth Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.45–2.57 Å. The Fe–C bond length is 1.92 Å. In the fifth Fe site, Fe is bonded in a single-bond geometry to one Cr, four Fe, and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.44–2.46 Å. The Fe–C bond length is 1.85 Å. In the sixth Fe site, Fe is bonded in a single-bond geometry to one Cr, four Fe, and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.43–2.48 Å. The Fe–C bond length is 1.86 Å. In the seventh Fe site, Fe is bonded to two Sm, one Cr, and nine Fe atoms to form distorted FeSm2CrFe9 cuboctahedra that share corners with eight FeSm3CrFe8 cuboctahedra, corners with four equivalent CSm2Fe4 octahedra, edges with three FeSm2CrFe9 cuboctahedra, edges with two equivalent CSm2Fe4 octahedra, and faces with nine FeSm3CrFe8 cuboctahedra. The corner-sharing octahedra tilt angles range from 22–28°. There are a spread of Fe–Fe bond distances ranging from 2.44–2.70 Å. In the eighth Fe site, Fe is bonded to two Sm, one Cr, and nine Fe atoms to form distorted FeSm2CrFe9 cuboctahedra that share corners with eight FeSm3CrFe8 cuboctahedra, corners with two equivalent CSm2Fe4 octahedra, edges with four FeSm3CrFe8 cuboctahedra, faces with eight FeSm3CrFe8 cuboctahedra, and faces with two equivalent CSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 46–48°. The Fe–Fe bond length is 2.67 Å. In the ninth Fe site, Fe is bonded to two Sm, one Cr, and nine Fe atoms to form distorted FeSm2CrFe9 cuboctahedra that share corners with fourteen FeSm3CrFe8 cuboctahedra, edges with two FeSm3Fe9 cuboctahedra, faces with ten FeSm3CrFe8 cuboctahedra, and faces with four equivalent CSm2Fe4 octahedra. The Fe–Fe bond length is 2.68 Å. In the tenth Fe site, Fe is bonded in a distorted single-bond geometry to one Cr and six Fe atoms. C is bonded to two Sm and four Fe atoms to form CSm2Fe4 octahedra that share corners with ten FeSm3CrFe8 cuboctahedra, corners with two equivalent CSm2Fe4 octahedra, edges with two equivalent FeSm2CrFe9 cuboctahedra, and faces with six FeSm3Fe9 cuboctahedra. The corner-sharing octahedra tilt angles range from 63–64°.