Sm2Fe12Ga5 crystallizes in the trigonal R-3m space group. Sm(1) is bonded in a 19-coordinate geometry to six equivalent Fe(1), nine equivalent Fe(2), one Ga(2), and three equivalent Ga(1) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 12-coordinate geometry to two equivalent Sm(1), two equivalent Fe(1), four equivalent Fe(2), two equivalent Ga(1), and two equivalent Ga(2) atoms. In the second Fe site, Fe(2) is bonded to three equivalent Sm(1), two equivalent Fe(2), four equivalent Fe(1), one Ga(2), and two equivalent Ga(1) atoms to form distorted FeSm3Ga3Fe6 cuboctahedra that share corners with five equivalent Ga(1)Sm2Ga2Fe8 cuboctahedra, corners with ten equivalent Fe(2)Sm3Ga3Fe6 cuboctahedra, edges with three equivalent Ga(1)Sm2Ga2Fe8 cuboctahedra, edges with five equivalent Fe(2)Sm3Ga3Fe6 cuboctahedra, faces with three equivalent Ga(1)Sm2Ga2Fe8 cuboctahedra, and faces with seven equivalent Fe(2)Sm3Ga3Fe6 cuboctahedra. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to two equivalent Sm(1), four equivalent Fe(1), four equivalent Fe(2), and two equivalent Ga(2) atoms to form distorted GaSm2Ga2Fe8 cuboctahedra that share corners with four equivalent Ga(1)Sm2Ga2Fe8 cuboctahedra, corners with ten equivalent Fe(2)Sm3Ga3Fe6 cuboctahedra, edges with six equivalent Fe(2)Sm3Ga3Fe6 cuboctahedra, faces with four equivalent Ga(1)Sm2Ga2Fe8 cuboctahedra, and faces with six equivalent Fe(2)Sm3Ga3Fe6 cuboctahedra. In the second Ga site, Ga(2) is bonded in a 14-coordinate geometry to one Sm(1), three equivalent Fe(2), six equivalent Fe(1), one Ga(2), and three equivalent Ga(1) atoms.
Sm2Fe12Ga5 crystallizes in the trigonal R-3m space group. Sm(1) is bonded in a 19-coordinate geometry to six equivalent Fe(1), nine equivalent Fe(2), one Ga(2), and three equivalent Ga(1) atoms. All Sm(1)-Fe(1) bond lengths are 3.02 Å. There are a spread of Sm(1)-Fe(2) bond distances ranging from 3.08-3.37 Å. The Sm(1)-Ga(2) bond length is 3.22 Å. All Sm(1)-Ga(1) bond lengths are 3.41 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 12-coordinate geometry to two equivalent Sm(1), two equivalent Fe(1), four equivalent Fe(2), two equivalent Ga(1), and two equivalent Ga(2) atoms. Both Fe(1)-Fe(1) bond lengths are 2.63 Å. There are two shorter (2.59 Å) and two longer (2.65 Å) Fe(1)-Fe(2) bond lengths. Both Fe(1)-Ga(1) bond lengths are 2.51 Å. Both Fe(1)-Ga(2) bond lengths are 2.91 Å. In the second Fe site, Fe(2) is bonded to three equivalent Sm(1), two equivalent Fe(2), four equivalent Fe(1), one Ga(2), and two equivalent Ga(1) atoms to form distorted FeSm3Ga3Fe6 cuboctahedra that share corners with five equivalent Ga(1)Sm2Ga2Fe8 cuboctahedra, corners with ten equivalent Fe(2)Sm3Ga3Fe6 cuboctahedra, edges with three equivalent Ga(1)Sm2Ga2Fe8 cuboctahedra, edges with five equivalent Fe(2)Sm3Ga3Fe6 cuboctahedra, faces with three equivalent Ga(1)Sm2Ga2Fe8 cuboctahedra, and faces with seven equivalent Fe(2)Sm3Ga3Fe6 cuboctahedra. Both Fe(2)-Fe(2) bond lengths are 2.47 Å. The Fe(2)-Ga(2) bond length is 2.72 Å. Both Fe(2)-Ga(1) bond lengths are 2.52 Å. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to two equivalent Sm(1), four equivalent Fe(1), four equivalent Fe(2), and two equivalent Ga(2) atoms to form distorted GaSm2Ga2Fe8 cuboctahedra that share corners with four equivalent Ga(1)Sm2Ga2Fe8 cuboctahedra, corners with ten equivalent Fe(2)Sm3Ga3Fe6 cuboctahedra, edges with six equivalent Fe(2)Sm3Ga3Fe6 cuboctahedra, faces with four equivalent Ga(1)Sm2Ga2Fe8 cuboctahedra, and faces with six equivalent Fe(2)Sm3Ga3Fe6 cuboctahedra. Both Ga(1)-Ga(2) bond lengths are 2.65 Å. In the second Ga site, Ga(2) is bonded in a 14-coordinate geometry to one Sm(1), three equivalent Fe(2), six equivalent Fe(1), one Ga(2), and three equivalent Ga(1) atoms. The Ga(2)-Ga(2) bond length is 2.45 Å.