Sm12(MnC3)5 crystallizes in the hexagonal P-62m space group. There are three inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a rectangular see-saw-like geometry to two equivalent C(2) and two equivalent C(4) atoms. In the second Sm site, Sm(2) is bonded to one C(1), one C(2), two equivalent C(3), and two equivalent C(4) atoms to form distorted SmC6 square pyramids that share corners with six equivalent Sm(2)C6 square pyramids, edges with two equivalent Sm(3)C8 hexagonal bipyramids, edges with two equivalent Sm(2)C6 square pyramids, and faces with two equivalent Sm(3)C8 hexagonal bipyramids. In the third Sm site, Sm(3) is bonded to two equivalent C(1), two equivalent C(3), and four equivalent C(4) atoms to form distorted SmC8 hexagonal bipyramids that share corners with four equivalent Sm(3)C8 hexagonal bipyramids, edges with two equivalent Sm(3)C8 hexagonal bipyramids, edges with four equivalent Sm(2)C6 square pyramids, and faces with four equivalent Sm(2)C6 square pyramids. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a distorted trigonal non-coplanar geometry to one C(1) and two equivalent C(2) atoms. In the second Mn site, Mn(2) is bonded in a trigonal planar geometry to three equivalent C(4) atoms. There are four inequivalent C sites. In the first C site, C(1) is bonded in a 6-coordinate geometry to two equivalent Sm(2), two equivalent Sm(3), one Mn(1), and one C(3) atom. In the second C site, C(2) is bonded to two equivalent Sm(1), two equivalent Sm(2), and two equivalent Mn(1) atoms to form CSm4Mn2 octahedra that share corners with four equivalent C(2)Sm4Mn2 octahedra and edges with four equivalent C(4)Sm5Mn octahedra. The corner-sharing octahedral tilt angles range from 2-33°. In the third C site, C(3) is bonded in a 7-coordinate geometry to two equivalent Sm(3), four equivalent Sm(2), and one C(1) atom. In the fourth C site, C(4) is bonded to one Sm(1), two equivalent Sm(2), two equivalent Sm(3), and one Mn(2) atom to form distorted CSm5Mn octahedra that share corners with five equivalent C(4)Sm5Mn octahedra, edges with two equivalent C(2)Sm4Mn2 octahedra, and edges with three equivalent C(4)Sm5Mn octahedra. The corner-sharing octahedral tilt angles range from 10-38°.
Sm12(MnC3)5 crystallizes in the hexagonal P-62m space group. There are three inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a rectangular see-saw-like geometry to two equivalent C(2) and two equivalent C(4) atoms. Both Sm(1)-C(2) bond lengths are 2.62 Å. Both Sm(1)-C(4) bond lengths are 2.61 Å. In the second Sm site, Sm(2) is bonded to one C(1), one C(2), two equivalent C(3), and two equivalent C(4) atoms to form distorted SmC6 square pyramids that share corners with six equivalent Sm(2)C6 square pyramids, edges with two equivalent Sm(3)C8 hexagonal bipyramids, edges with two equivalent Sm(2)C6 square pyramids, and faces with two equivalent Sm(3)C8 hexagonal bipyramids. The Sm(2)-C(1) bond length is 2.50 Å. The Sm(2)-C(2) bond length is 2.44 Å. There is one shorter (2.62 Å) and one longer (2.85 Å) Sm(2)-C(3) bond length. Both Sm(2)-C(4) bond lengths are 2.62 Å. In the third Sm site, Sm(3) is bonded to two equivalent C(1), two equivalent C(3), and four equivalent C(4) atoms to form distorted SmC8 hexagonal bipyramids that share corners with four equivalent Sm(3)C8 hexagonal bipyramids, edges with two equivalent Sm(3)C8 hexagonal bipyramids, edges with four equivalent Sm(2)C6 square pyramids, and faces with four equivalent Sm(2)C6 square pyramids. Both Sm(3)-C(1) bond lengths are 2.83 Å. Both Sm(3)-C(3) bond lengths are 2.63 Å. There are two shorter (2.74 Å) and two longer (2.78 Å) Sm(3)-C(4) bond lengths. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a distorted trigonal non-coplanar geometry to one C(1) and two equivalent C(2) atoms. The Mn(1)-C(1) bond length is 1.83 Å. Both Mn(1)-C(2) bond lengths are 1.94 Å. In the second Mn site, Mn(2) is bonded in a trigonal planar geometry to three equivalent C(4) atoms. All Mn(2)-C(4) bond lengths are 1.77 Å. There are four inequivalent C sites. In the first C site, C(1) is bonded in a 6-coordinate geometry to two equivalent Sm(2), two equivalent Sm(3), one Mn(1), and one C(3) atom. The C(1)-C(3) bond length is 1.34 Å. In the second C site, C(2) is bonded to two equivalent Sm(1), two equivalent Sm(2), and two equivalent Mn(1) atoms to form CSm4Mn2 octahedra that share corners with four equivalent C(2)Sm4Mn2 octahedra and edges with four equivalent C(4)Sm5Mn octahedra. The corner-sharing octahedral tilt angles range from 2-33°. In the third C site, C(3) is bonded in a 7-coordinate geometry to two equivalent Sm(3), four equivalent Sm(2), and one C(1) atom. In the fourth C site, C(4) is bonded to one Sm(1), two equivalent Sm(2), two equivalent Sm(3), and one Mn(2) atom to form distorted CSm5Mn octahedra that share corners with five equivalent C(4)Sm5Mn octahedra, edges with two equivalent C(2)Sm4Mn2 octahedra, and edges with three equivalent C(4)Sm5Mn octahedra. The corner-sharing octahedral tilt angles range from 10-38°.