Sm2VCo16 crystallizes in the trigonal R3m space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 19-coordinate geometry to one Co(5), three equivalent Co(1), three equivalent Co(4), six equivalent Co(2), and six equivalent Co(3) atoms. In the second Sm site, Sm(2) is bonded in a 19-coordinate geometry to one V(1), three equivalent Co(2), three equivalent Co(4), six equivalent Co(1), and six equivalent Co(3) atoms. V(1) is bonded in a 14-coordinate geometry to one Sm(2), one Co(5), three equivalent Co(1), three equivalent Co(4), and six equivalent Co(3) atoms. There are five inequivalent Co sites. In the first Co site, Co(1) is bonded to one Sm(1), two equivalent Sm(2), one V(1), two equivalent Co(2), two equivalent Co(4), and four equivalent Co(3) atoms to form CoSm3VCo8 cuboctahedra that share corners with two equivalent Co(1)Sm3VCo8 cuboctahedra, corners with five equivalent Co(4)Sm2VCo9 cuboctahedra, corners with eight equivalent Co(3)Sm2VCo9 cuboctahedra, corners with eight equivalent Co(2)Sm3Co9 cuboctahedra,  an edgeedge with one Co(2)Sm3Co9 cuboctahedra, edges with two equivalent Co(3)Sm2VCo9 cuboctahedra, edges with three equivalent Co(4)Sm2VCo9 cuboctahedra, edges with four equivalent Co(1)Sm3VCo8 cuboctahedra, faces with three equivalent Co(4)Sm2VCo9 cuboctahedra, faces with three equivalent Co(2)Sm3Co9 cuboctahedra, faces with four equivalent Co(1)Sm3VCo8 cuboctahedra, and faces with ten equivalent Co(3)Sm2VCo9 cuboctahedra. In the second Co site, Co(2) is bonded to one Sm(2), two equivalent Sm(1), one Co(5), two equivalent Co(1), two equivalent Co(4), and four equivalent Co(3) atoms to form CoSm3Co9 cuboctahedra that share corners with two equivalent Co(2)Sm3Co9 cuboctahedra, corners with five equivalent Co(4)Sm2VCo9 cuboctahedra, corners with eight equivalent Co(3)Sm2VCo9 cuboctahedra, corners with eight equivalent Co(1)Sm3VCo8 cuboctahedra,  an edgeedge with one Co(1)Sm3VCo8 cuboctahedra, edges with two equivalent Co(3)Sm2VCo9 cuboctahedra, edges with three equivalent Co(4)Sm2VCo9 cuboctahedra, edges with four equivalent Co(2)Sm3Co9 cuboctahedra, faces with three equivalent Co(4)Sm2VCo9 cuboctahedra, faces with three equivalent Co(1)Sm3VCo8 cuboctahedra, faces with four equivalent Co(2)Sm3Co9 cuboctahedra, and faces with ten equivalent Co(3)Sm2VCo9 cuboctahedra. In the third Co site, Co(3) is bonded to one Sm(1), one Sm(2), one V(1), one Co(5), two equivalent Co(1), two equivalent Co(2), two equivalent Co(3), and two equivalent Co(4) atoms to form distorted CoSm2VCo9 cuboctahedra that share corners with four equivalent Co(4)Sm2VCo9 cuboctahedra, corners with four equivalent Co(2)Sm3Co9 cuboctahedra, corners with four equivalent Co(1)Sm3VCo8 cuboctahedra, corners with twelve equivalent Co(3)Sm2VCo9 cuboctahedra,  an edgeedge with one Co(3)Sm2VCo9 cuboctahedra,  an edgeedge with one Co(2)Sm3Co9 cuboctahedra,  an edgeedge with one Co(1)Sm3VCo8 cuboctahedra, edges with two equivalent Co(4)Sm2VCo9 cuboctahedra, faces with four equivalent Co(4)Sm2VCo9 cuboctahedra, faces with five equivalent Co(2)Sm3Co9 cuboctahedra, faces with five equivalent Co(1)Sm3VCo8 cuboctahedra, and faces with seven equivalent Co(3)Sm2VCo9 cuboctahedra. In the fourth Co site, Co(4) is bonded to one Sm(1), one Sm(2), one V(1), one Co(5), two equivalent Co(1), two equivalent Co(2), and four equivalent Co(3) atoms to form distorted CoSm2VCo9 cuboctahedra that share corners with four equivalent Co(4)Sm2VCo9 cuboctahedra, corners with five equivalent Co(2)Sm3Co9 cuboctahedra, corners with five equivalent Co(1)Sm3VCo8 cuboctahedra, corners with eight equivalent Co(3)Sm2VCo9 cuboctahedra, edges with three equivalent Co(2)Sm3Co9 cuboctahedra, edges with three equivalent Co(1)Sm3VCo8 cuboctahedra, edges with four equivalent Co(3)Sm2VCo9 cuboctahedra, faces with three equivalent Co(2)Sm3Co9 cuboctahedra, faces with three equivalent Co(1)Sm3VCo8 cuboctahedra, faces with four equivalent Co(4)Sm2VCo9 cuboctahedra, and faces with eight equivalent Co(3)Sm2VCo9 cuboctahedra. In the fifth Co site, Co(5) is bonded in a distorted single-bond geometry to one Sm(1), one V(1), three equivalent Co(2), three equivalent Co(4), and six equivalent Co(3) atoms.
Sm2VCo16 crystallizes in the trigonal R3m space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 19-coordinate geometry to one Co(5), three equivalent Co(1), three equivalent Co(4), six equivalent Co(2), and six equivalent Co(3) atoms. The Sm(1)-Co(5) bond length is 3.03 Å. All Sm(1)-Co(1) bond lengths are 3.02 Å. All Sm(1)-Co(4) bond lengths are 3.25 Å. There are three shorter (3.11 Å) and three longer (3.21 Å) Sm(1)-Co(2) bond lengths. All Sm(1)-Co(3) bond lengths are 2.99 Å. In the second Sm site, Sm(2) is bonded in a 19-coordinate geometry to one V(1), three equivalent Co(2), three equivalent Co(4), six equivalent Co(1), and six equivalent Co(3) atoms. The Sm(2)-V(1) bond length is 3.17 Å. All Sm(2)-Co(2) bond lengths are 2.98 Å. All Sm(2)-Co(4) bond lengths are 3.29 Å. There are three shorter (3.15 Å) and three longer (3.17 Å) Sm(2)-Co(1) bond lengths. All Sm(2)-Co(3) bond lengths are 3.01 Å. V(1) is bonded in a 14-coordinate geometry to one Sm(2), one Co(5), three equivalent Co(1), three equivalent Co(4), and six equivalent Co(3) atoms. The V(1)-Co(5) bond length is 2.28 Å. All V(1)-Co(1) bond lengths are 2.61 Å. All V(1)-Co(4) bond lengths are 2.59 Å. All V(1)-Co(3) bond lengths are 2.67 Å. There are five inequivalent Co sites. In the first Co site, Co(1) is bonded to one Sm(1), two equivalent Sm(2), one V(1), two equivalent Co(2), two equivalent Co(4), and four equivalent Co(3) atoms to form CoSm3VCo8 cuboctahedra that share corners with two equivalent Co(1)Sm3VCo8 cuboctahedra, corners with five equivalent Co(4)Sm2VCo9 cuboctahedra, corners with eight equivalent Co(3)Sm2VCo9 cuboctahedra, corners with eight equivalent Co(2)Sm3Co9 cuboctahedra,  an edgeedge with one Co(2)Sm3Co9 cuboctahedra, edges with two equivalent Co(3)Sm2VCo9 cuboctahedra, edges with three equivalent Co(4)Sm2VCo9 cuboctahedra, edges with four equivalent Co(1)Sm3VCo8 cuboctahedra, faces with three equivalent Co(4)Sm2VCo9 cuboctahedra, faces with three equivalent Co(2)Sm3Co9 cuboctahedra, faces with four equivalent Co(1)Sm3VCo8 cuboctahedra, and faces with ten equivalent Co(3)Sm2VCo9 cuboctahedra. Both Co(1)-Co(2) bond lengths are 2.48 Å. Both Co(1)-Co(4) bond lengths are 2.40 Å. There are two shorter (2.53 Å) and two longer (2.57 Å) Co(1)-Co(3) bond lengths. In the second Co site, Co(2) is bonded to one Sm(2), two equivalent Sm(1), one Co(5), two equivalent Co(1), two equivalent Co(4), and four equivalent Co(3) atoms to form CoSm3Co9 cuboctahedra that share corners with two equivalent Co(2)Sm3Co9 cuboctahedra, corners with five equivalent Co(4)Sm2VCo9 cuboctahedra, corners with eight equivalent Co(3)Sm2VCo9 cuboctahedra, corners with eight equivalent Co(1)Sm3VCo8 cuboctahedra,  an edgeedge with one Co(1)Sm3VCo8 cuboctahedra, edges with two equivalent Co(3)Sm2VCo9 cuboctahedra, edges with three equivalent Co(4)Sm2VCo9 cuboctahedra, edges with four equivalent Co(2)Sm3Co9 cuboctahedra, faces with three equivalent Co(4)Sm2VCo9 cuboctahedra, faces with three equivalent Co(1)Sm3VCo8 cuboctahedra, faces with four equivalent Co(2)Sm3Co9 cuboctahedra, and faces with ten equivalent Co(3)Sm2VCo9 cuboctahedra. The Co(2)-Co(5) bond length is 2.58 Å. Both Co(2)-Co(4) bond lengths are 2.40 Å. There are two shorter (2.50 Å) and two longer (2.59 Å) Co(2)-Co(3) bond lengths. In the third Co site, Co(3) is bonded to one Sm(1), one Sm(2), one V(1), one Co(5), two equivalent Co(1), two equivalent Co(2), two equivalent Co(3), and two equivalent Co(4) atoms to form distorted CoSm2VCo9 cuboctahedra that share corners with four equivalent Co(4)Sm2VCo9 cuboctahedra, corners with four equivalent Co(2)Sm3Co9 cuboctahedra, corners with four equivalent Co(1)Sm3VCo8 cuboctahedra, corners with twelve equivalent Co(3)Sm2VCo9 cuboctahedra,  an edgeedge with one Co(3)Sm2VCo9 cuboctahedra,  an edgeedge with one Co(2)Sm3Co9 cuboctahedra,  an edgeedge with one Co(1)Sm3VCo8 cuboctahedra, edges with two equivalent Co(4)Sm2VCo9 cuboctahedra, faces with four equivalent Co(4)Sm2VCo9 cuboctahedra, faces with five equivalent Co(2)Sm3Co9 cuboctahedra, faces with five equivalent Co(1)Sm3VCo8 cuboctahedra, and faces with seven equivalent Co(3)Sm2VCo9 cuboctahedra. The Co(3)-Co(5) bond length is 2.68 Å. There is one shorter (2.41 Å) and one longer (2.43 Å) Co(3)-Co(3) bond length. There is one shorter (2.38 Å) and one longer (2.41 Å) Co(3)-Co(4) bond length. In the fourth Co site, Co(4) is bonded to one Sm(1), one Sm(2), one V(1), one Co(5), two equivalent Co(1), two equivalent Co(2), and four equivalent Co(3) atoms to form distorted CoSm2VCo9 cuboctahedra that share corners with four equivalent Co(4)Sm2VCo9 cuboctahedra, corners with five equivalent Co(2)Sm3Co9 cuboctahedra, corners with five equivalent Co(1)Sm3VCo8 cuboctahedra, corners with eight equivalent Co(3)Sm2VCo9 cuboctahedra, edges with three equivalent Co(2)Sm3Co9 cuboctahedra, edges with three equivalent Co(1)Sm3VCo8 cuboctahedra, edges with four equivalent Co(3)Sm2VCo9 cuboctahedra, faces with three equivalent Co(2)Sm3Co9 cuboctahedra, faces with three equivalent Co(1)Sm3VCo8 cuboctahedra, faces with four equivalent Co(4)Sm2VCo9 cuboctahedra, and faces with eight equivalent Co(3)Sm2VCo9 cuboctahedra. The Co(4)-Co(5) bond length is 2.57 Å. In the fifth Co site, Co(5) is bonded in a distorted single-bond geometry to one Sm(1), one V(1), three equivalent Co(2), three equivalent Co(4), and six equivalent Co(3) atoms.