Ce2Fe12Co5 crystallizes in the trigonal R-3m space group. Ce(1) is bonded in a 19-coordinate geometry to six equivalent Fe(1), nine equivalent Fe(2), one Co(2), and three equivalent Co(1) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Ce(1), two equivalent Fe(1), four equivalent Fe(2), two equivalent Co(1), and two equivalent Co(2) atoms to form distorted FeCe2Fe6Co4 cuboctahedra that share corners with four equivalent Co(1)Ce2Fe8Co2 cuboctahedra, corners with eight equivalent Fe(2)Ce3Fe6Co3 cuboctahedra, corners with twelve equivalent Fe(1)Ce2Fe6Co4 cuboctahedra,  an edgeedge with one Fe(1)Ce2Fe6Co4 cuboctahedra, edges with two equivalent Fe(2)Ce3Fe6Co3 cuboctahedra, edges with two equivalent Co(1)Ce2Fe8Co2 cuboctahedra, faces with four equivalent Co(1)Ce2Fe8Co2 cuboctahedra, faces with seven equivalent Fe(1)Ce2Fe6Co4 cuboctahedra, and faces with ten equivalent Fe(2)Ce3Fe6Co3 cuboctahedra. In the second Fe site, Fe(2) is bonded to three equivalent Ce(1), two equivalent Fe(2), four equivalent Fe(1), one Co(2), and two equivalent Co(1) atoms to form FeCe3Fe6Co3 cuboctahedra that share corners with five equivalent Co(1)Ce2Fe8Co2 cuboctahedra, corners with eight equivalent Fe(1)Ce2Fe6Co4 cuboctahedra, corners with ten equivalent Fe(2)Ce3Fe6Co3 cuboctahedra, edges with two equivalent Fe(1)Ce2Fe6Co4 cuboctahedra, edges with three equivalent Co(1)Ce2Fe8Co2 cuboctahedra, edges with five equivalent Fe(2)Ce3Fe6Co3 cuboctahedra, faces with three equivalent Co(1)Ce2Fe8Co2 cuboctahedra, faces with seven equivalent Fe(2)Ce3Fe6Co3 cuboctahedra, and faces with ten equivalent Fe(1)Ce2Fe6Co4 cuboctahedra. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent Ce(1), four equivalent Fe(1), four equivalent Fe(2), and two equivalent Co(2) atoms to form distorted CoCe2Fe8Co2 cuboctahedra that share corners with four equivalent Co(1)Ce2Fe8Co2 cuboctahedra, corners with eight equivalent Fe(1)Ce2Fe6Co4 cuboctahedra, corners with ten equivalent Fe(2)Ce3Fe6Co3 cuboctahedra, edges with four equivalent Fe(1)Ce2Fe6Co4 cuboctahedra, edges with six equivalent Fe(2)Ce3Fe6Co3 cuboctahedra, faces with four equivalent Co(1)Ce2Fe8Co2 cuboctahedra, faces with six equivalent Fe(2)Ce3Fe6Co3 cuboctahedra, and faces with eight equivalent Fe(1)Ce2Fe6Co4 cuboctahedra. In the second Co site, Co(2) is bonded in a 14-coordinate geometry to one Ce(1), three equivalent Fe(2), six equivalent Fe(1), one Co(2), and three equivalent Co(1) atoms.
Ce2Fe12Co5 crystallizes in the trigonal R-3m space group. Ce(1) is bonded in a 19-coordinate geometry to six equivalent Fe(1), nine equivalent Fe(2), one Co(2), and three equivalent Co(1) atoms. All Ce(1)-Fe(1) bond lengths are 3.01 Å. There are a spread of Ce(1)-Fe(2) bond distances ranging from 3.07-3.21 Å. The Ce(1)-Co(2) bond length is 3.17 Å. All Ce(1)-Co(1) bond lengths are 3.30 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Ce(1), two equivalent Fe(1), four equivalent Fe(2), two equivalent Co(1), and two equivalent Co(2) atoms to form distorted FeCe2Fe6Co4 cuboctahedra that share corners with four equivalent Co(1)Ce2Fe8Co2 cuboctahedra, corners with eight equivalent Fe(2)Ce3Fe6Co3 cuboctahedra, corners with twelve equivalent Fe(1)Ce2Fe6Co4 cuboctahedra,  an edgeedge with one Fe(1)Ce2Fe6Co4 cuboctahedra, edges with two equivalent Fe(2)Ce3Fe6Co3 cuboctahedra, edges with two equivalent Co(1)Ce2Fe8Co2 cuboctahedra, faces with four equivalent Co(1)Ce2Fe8Co2 cuboctahedra, faces with seven equivalent Fe(1)Ce2Fe6Co4 cuboctahedra, and faces with ten equivalent Fe(2)Ce3Fe6Co3 cuboctahedra. Both Fe(1)-Fe(1) bond lengths are 2.44 Å. There are two shorter (2.54 Å) and two longer (2.65 Å) Fe(1)-Fe(2) bond lengths. Both Fe(1)-Co(1) bond lengths are 2.44 Å. Both Fe(1)-Co(2) bond lengths are 2.70 Å. In the second Fe site, Fe(2) is bonded to three equivalent Ce(1), two equivalent Fe(2), four equivalent Fe(1), one Co(2), and two equivalent Co(1) atoms to form FeCe3Fe6Co3 cuboctahedra that share corners with five equivalent Co(1)Ce2Fe8Co2 cuboctahedra, corners with eight equivalent Fe(1)Ce2Fe6Co4 cuboctahedra, corners with ten equivalent Fe(2)Ce3Fe6Co3 cuboctahedra, edges with two equivalent Fe(1)Ce2Fe6Co4 cuboctahedra, edges with three equivalent Co(1)Ce2Fe8Co2 cuboctahedra, edges with five equivalent Fe(2)Ce3Fe6Co3 cuboctahedra, faces with three equivalent Co(1)Ce2Fe8Co2 cuboctahedra, faces with seven equivalent Fe(2)Ce3Fe6Co3 cuboctahedra, and faces with ten equivalent Fe(1)Ce2Fe6Co4 cuboctahedra. Both Fe(2)-Fe(2) bond lengths are 2.48 Å. The Fe(2)-Co(2) bond length is 2.62 Å. Both Fe(2)-Co(1) bond lengths are 2.42 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent Ce(1), four equivalent Fe(1), four equivalent Fe(2), and two equivalent Co(2) atoms to form distorted CoCe2Fe8Co2 cuboctahedra that share corners with four equivalent Co(1)Ce2Fe8Co2 cuboctahedra, corners with eight equivalent Fe(1)Ce2Fe6Co4 cuboctahedra, corners with ten equivalent Fe(2)Ce3Fe6Co3 cuboctahedra, edges with four equivalent Fe(1)Ce2Fe6Co4 cuboctahedra, edges with six equivalent Fe(2)Ce3Fe6Co3 cuboctahedra, faces with four equivalent Co(1)Ce2Fe8Co2 cuboctahedra, faces with six equivalent Fe(2)Ce3Fe6Co3 cuboctahedra, and faces with eight equivalent Fe(1)Ce2Fe6Co4 cuboctahedra. Both Co(1)-Co(2) bond lengths are 2.60 Å. In the second Co site, Co(2) is bonded in a 14-coordinate geometry to one Ce(1), three equivalent Fe(2), six equivalent Fe(1), one Co(2), and three equivalent Co(1) atoms. The Co(2)-Co(2) bond length is 2.33 Å.