Sm2Co15Ga2 crystallizes in the trigonal R-3m space group. Sm(1) is bonded in a 19-coordinate geometry to three equivalent Co(1), six equivalent Co(2), nine equivalent Co(3), and one Ga(1) atom. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent Sm(1), four equivalent Co(2), four equivalent Co(3), and two equivalent Ga(1) atoms to form distorted CoSm2Ga2Co8 cuboctahedra that share corners with four equivalent Co(1)Sm2Ga2Co8 cuboctahedra, corners with ten equivalent Co(3)Sm3GaCo8 cuboctahedra, edges with six equivalent Co(3)Sm3GaCo8 cuboctahedra, faces with four equivalent Co(1)Sm2Ga2Co8 cuboctahedra, and faces with six equivalent Co(3)Sm3GaCo8 cuboctahedra. In the second Co site, Co(2) is bonded in a distorted q6 geometry to two equivalent Sm(1), two equivalent Co(1), two equivalent Co(2), four equivalent Co(3), and two equivalent Ga(1) atoms. In the third Co site, Co(3) is bonded to three equivalent Sm(1), two equivalent Co(1), two equivalent Co(3), four equivalent Co(2), and one Ga(1) atom to form CoSm3GaCo8 cuboctahedra that share corners with five equivalent Co(1)Sm2Ga2Co8 cuboctahedra, corners with ten equivalent Co(3)Sm3GaCo8 cuboctahedra, edges with three equivalent Co(1)Sm2Ga2Co8 cuboctahedra, edges with five equivalent Co(3)Sm3GaCo8 cuboctahedra, faces with three equivalent Co(1)Sm2Ga2Co8 cuboctahedra, and faces with seven equivalent Co(3)Sm3GaCo8 cuboctahedra. Ga(1) is bonded in a 14-coordinate geometry to one Sm(1), three equivalent Co(1), three equivalent Co(3), six equivalent Co(2), and one Ga(1) atom.
Sm2Co15Ga2 crystallizes in the trigonal R-3m space group. Sm(1) is bonded in a 19-coordinate geometry to three equivalent Co(1), six equivalent Co(2), nine equivalent Co(3), and one Ga(1) atom. All Sm(1)-Co(1) bond lengths are 3.32 Å. All Sm(1)-Co(2) bond lengths are 3.02 Å. There are a spread of Sm(1)-Co(3) bond distances ranging from 2.93-3.19 Å. The Sm(1)-Ga(1) bond length is 3.00 Å. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent Sm(1), four equivalent Co(2), four equivalent Co(3), and two equivalent Ga(1) atoms to form distorted CoSm2Ga2Co8 cuboctahedra that share corners with four equivalent Co(1)Sm2Ga2Co8 cuboctahedra, corners with ten equivalent Co(3)Sm3GaCo8 cuboctahedra, edges with six equivalent Co(3)Sm3GaCo8 cuboctahedra, faces with four equivalent Co(1)Sm2Ga2Co8 cuboctahedra, and faces with six equivalent Co(3)Sm3GaCo8 cuboctahedra. All Co(1)-Co(2) bond lengths are 2.41 Å. All Co(1)-Co(3) bond lengths are 2.44 Å. Both Co(1)-Ga(1) bond lengths are 2.54 Å. In the second Co site, Co(2) is bonded in a distorted q6 geometry to two equivalent Sm(1), two equivalent Co(1), two equivalent Co(2), four equivalent Co(3), and two equivalent Ga(1) atoms. Both Co(2)-Co(2) bond lengths are 2.43 Å. All Co(2)-Co(3) bond lengths are 2.57 Å. Both Co(2)-Ga(1) bond lengths are 2.76 Å. In the third Co site, Co(3) is bonded to three equivalent Sm(1), two equivalent Co(1), two equivalent Co(3), four equivalent Co(2), and one Ga(1) atom to form CoSm3GaCo8 cuboctahedra that share corners with five equivalent Co(1)Sm2Ga2Co8 cuboctahedra, corners with ten equivalent Co(3)Sm3GaCo8 cuboctahedra, edges with three equivalent Co(1)Sm2Ga2Co8 cuboctahedra, edges with five equivalent Co(3)Sm3GaCo8 cuboctahedra, faces with three equivalent Co(1)Sm2Ga2Co8 cuboctahedra, and faces with seven equivalent Co(3)Sm3GaCo8 cuboctahedra. Both Co(3)-Co(3) bond lengths are 2.46 Å. The Co(3)-Ga(1) bond length is 2.60 Å. Ga(1) is bonded in a 14-coordinate geometry to one Sm(1), three equivalent Co(1), three equivalent Co(3), six equivalent Co(2), and one Ga(1) atom. The Ga(1)-Ga(1) bond length is 2.62 Å.