Ce2Co7 crystallizes in the trigonal R-3m space group. There are five inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 6-coordinate geometry to three equivalent Co(2); three equivalent Co(3); six Co(4,4,4); and six equivalent Co(5) atoms. In the second Ce site, Ce(1) is bonded in a 6-coordinate geometry to three equivalent Co(2); three equivalent Co(3); six Co(4,4,4); and six equivalent Co(5) atoms. In the third Ce site, Ce(2) is bonded in a 9-coordinate geometry to three equivalent Co(1) and nine equivalent Co(5) atoms. In the fourth Ce site, Ce(1) is bonded in a 6-coordinate geometry to three equivalent Co(2); three equivalent Co(3); six Co(4,4); and six equivalent Co(5) atoms. In the fifth Ce site, Ce(1) is bonded in a 6-coordinate geometry to three equivalent Co(2); three equivalent Co(3); six Co(4,4); and six equivalent Co(5) atoms. There are eight inequivalent Co sites. In the first Co site, Co(4) is bonded to four Ce(1,1); two equivalent Co(2); two equivalent Co(3); and four Co(4,4) atoms to form CoCe4Co8 cuboctahedra that share corners with four equivalent Co(4)Ce4Co8 cuboctahedra; corners with twelve equivalent Co(5)Ce5Co7 cuboctahedra; edges with two equivalent Co(4)Ce4Co8 cuboctahedra; edges with eight equivalent Co(5)Ce5Co7 cuboctahedra; faces with two equivalent Co(5)Ce5Co7 cuboctahedra; and faces with eight Co(4,4)Ce4Co8 cuboctahedra. In the second Co site, Co(1) is bonded to six equivalent Ce(2) and six equivalent Co(5) atoms to form CoCe6Co6 cuboctahedra that share corners with twelve equivalent Co(5)Ce5Co7 cuboctahedra, edges with six equivalent Co(1)Ce6Co6 cuboctahedra, and faces with eighteen equivalent Co(5)Ce5Co7 cuboctahedra. In the third Co site, Co(2) is bonded in a 12-coordinate geometry to three equivalent Ce(1); three equivalent Co(3); three Co(4,4,4); and three equivalent Co(5) atoms. In the fourth Co site, Co(3) is bonded in a 12-coordinate geometry to three equivalent Ce(1); three equivalent Co(2); three Co(4,4,4); and three equivalent Co(5) atoms. In the fifth Co site, Co(4) is bonded to four equivalent Ce(1); two equivalent Co(2); two equivalent Co(3); and four Co(4,4) atoms to form CoCe4Co8 cuboctahedra that share corners with four equivalent Co(4)Ce4Co8 cuboctahedra; corners with twelve equivalent Co(5)Ce5Co7 cuboctahedra; edges with two equivalent Co(4)Ce4Co8 cuboctahedra; edges with eight equivalent Co(5)Ce5Co7 cuboctahedra; faces with two equivalent Co(5)Ce5Co7 cuboctahedra; and faces with eight Co(4,4)Ce4Co8 cuboctahedra. In the sixth Co site, Co(4) is bonded to four equivalent Ce(1); two equivalent Co(2); two equivalent Co(3); and four Co(4,4) atoms to form CoCe4Co8 cuboctahedra that share corners with four equivalent Co(4)Ce4Co8 cuboctahedra; corners with twelve equivalent Co(5)Ce5Co7 cuboctahedra; edges with two equivalent Co(4)Ce4Co8 cuboctahedra; edges with eight equivalent Co(5)Ce5Co7 cuboctahedra; faces with two equivalent Co(5)Ce5Co7 cuboctahedra; and faces with eight Co(4,4)Ce4Co8 cuboctahedra. In the seventh Co site, Co(4) is bonded to four equivalent Ce(1); two equivalent Co(2); two equivalent Co(3); and four Co(4,4) atoms to form CoCe4Co8 cuboctahedra that share corners with four equivalent Co(4)Ce4Co8 cuboctahedra; corners with twelve equivalent Co(5)Ce5Co7 cuboctahedra; edges with two equivalent Co(4)Ce4Co8 cuboctahedra; edges with eight equivalent Co(5)Ce5Co7 cuboctahedra; faces with two equivalent Co(5)Ce5Co7 cuboctahedra; and faces with eight Co(4,4)Ce4Co8 cuboctahedra. In the eighth Co site, Co(5) is bonded to two equivalent Ce(1), three equivalent Ce(2), one Co(1), one Co(2), one Co(3), and four equivalent Co(5) atoms to form distorted CoCe5Co7 cuboctahedra that share corners with two equivalent Co(1)Ce6Co6 cuboctahedra; corners with six Co(4,4,4)Ce4Co8 cuboctahedra; corners with nine equivalent Co(5)Ce5Co7 cuboctahedra; edges with four Co(4,4)Ce4Co8 cuboctahedra; edges with four equivalent Co(5)Ce5Co7 cuboctahedra;  a faceface with one Co(4)Ce4Co8 cuboctahedra; faces with three equivalent Co(1)Ce6Co6 cuboctahedra; and faces with ten equivalent Co(5)Ce5Co7 cuboctahedra.
Ce2Co7 crystallizes in the trigonal R-3m space group. There are five inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 6-coordinate geometry to three equivalent Co(2); three equivalent Co(3); six Co(4,4,4); and six equivalent Co(5) atoms. All Ce(1)-Co(2) bond lengths are 2.82 Å. All Ce(1)-Co(3) bond lengths are 2.82 Å. All Ce(1)-Co(4,4,4) bond lengths are 3.10 Å. All Ce(1)-Co(5) bond lengths are 3.25 Å. In the second Ce site, Ce(1) is bonded in a 6-coordinate geometry to three equivalent Co(2); three equivalent Co(3); six Co(4,4,4); and six equivalent Co(5) atoms. All Ce(1)-Co(2) bond lengths are 2.82 Å. All Ce(1)-Co(3) bond lengths are 2.82 Å. All Ce(1)-Co(4,4,4) bond lengths are 3.10 Å. All Ce(1)-Co(5) bond lengths are 3.25 Å. In the third Ce site, Ce(2) is bonded in a 9-coordinate geometry to three equivalent Co(1) and nine equivalent Co(5) atoms. All Ce(2)-Co(1) bond lengths are 2.91 Å. There are six shorter (2.82 Å) and three longer (3.18 Å) Ce(2)-Co(5) bond lengths. In the fourth Ce site, Ce(1) is bonded in a 6-coordinate geometry to three equivalent Co(2); three equivalent Co(3); six Co(4,4); and six equivalent Co(5) atoms. All Ce(1)-Co(2) bond lengths are 2.82 Å. All Ce(1)-Co(3) bond lengths are 2.82 Å. All Ce(1)-Co(4,4) bond lengths are 3.10 Å. All Ce(1)-Co(5) bond lengths are 3.25 Å. In the fifth Ce site, Ce(1) is bonded in a 6-coordinate geometry to three equivalent Co(2); three equivalent Co(3); six Co(4,4); and six equivalent Co(5) atoms. All Ce(1)-Co(2) bond lengths are 2.82 Å. All Ce(1)-Co(3) bond lengths are 2.82 Å. All Ce(1)-Co(4,4) bond lengths are 3.10 Å. All Ce(1)-Co(5) bond lengths are 3.25 Å. There are eight inequivalent Co sites. In the first Co site, Co(4) is bonded to four Ce(1,1); two equivalent Co(2); two equivalent Co(3); and four Co(4,4) atoms to form CoCe4Co8 cuboctahedra that share corners with four equivalent Co(4)Ce4Co8 cuboctahedra; corners with twelve equivalent Co(5)Ce5Co7 cuboctahedra; edges with two equivalent Co(4)Ce4Co8 cuboctahedra; edges with eight equivalent Co(5)Ce5Co7 cuboctahedra; faces with two equivalent Co(5)Ce5Co7 cuboctahedra; and faces with eight Co(4,4)Ce4Co8 cuboctahedra. Both Co(4)-Ce(1) bond lengths are 3.10 Å. Both Co(4)-Co(2) bond lengths are 2.48 Å. Both Co(4)-Co(3) bond lengths are 2.48 Å. All Co(4)-Co(4,4) bond lengths are 2.44 Å. In the second Co site, Co(1) is bonded to six equivalent Ce(2) and six equivalent Co(5) atoms to form CoCe6Co6 cuboctahedra that share corners with twelve equivalent Co(5)Ce5Co7 cuboctahedra, edges with six equivalent Co(1)Ce6Co6 cuboctahedra, and faces with eighteen equivalent Co(5)Ce5Co7 cuboctahedra. All Co(1)-Co(5) bond lengths are 2.56 Å. In the third Co site, Co(2) is bonded in a 12-coordinate geometry to three equivalent Ce(1); three equivalent Co(3); three Co(4,4,4); and three equivalent Co(5) atoms. All Co(2)-Co(3) bond lengths are 2.82 Å. Both Co(2)-Co(4,4) bond lengths are 2.48 Å. All Co(2)-Co(5) bond lengths are 2.45 Å. In the fourth Co site, Co(3) is bonded in a 12-coordinate geometry to three equivalent Ce(1); three equivalent Co(2); three Co(4,4,4); and three equivalent Co(5) atoms. All Co(3)-Co(4,4,4) bond lengths are 2.48 Å. All Co(3)-Co(5) bond lengths are 2.46 Å. In the fifth Co site, Co(4) is bonded to four equivalent Ce(1); two equivalent Co(2); two equivalent Co(3); and four Co(4,4) atoms to form CoCe4Co8 cuboctahedra that share corners with four equivalent Co(4)Ce4Co8 cuboctahedra; corners with twelve equivalent Co(5)Ce5Co7 cuboctahedra; edges with two equivalent Co(4)Ce4Co8 cuboctahedra; edges with eight equivalent Co(5)Ce5Co7 cuboctahedra; faces with two equivalent Co(5)Ce5Co7 cuboctahedra; and faces with eight Co(4,4)Ce4Co8 cuboctahedra. Both Co(4)-Co(2) bond lengths are 2.48 Å. All Co(4)-Co(4,4) bond lengths are 2.44 Å. In the sixth Co site, Co(4) is bonded to four equivalent Ce(1); two equivalent Co(2); two equivalent Co(3); and four Co(4,4) atoms to form CoCe4Co8 cuboctahedra that share corners with four equivalent Co(4)Ce4Co8 cuboctahedra; corners with twelve equivalent Co(5)Ce5Co7 cuboctahedra; edges with two equivalent Co(4)Ce4Co8 cuboctahedra; edges with eight equivalent Co(5)Ce5Co7 cuboctahedra; faces with two equivalent Co(5)Ce5Co7 cuboctahedra; and faces with eight Co(4,4)Ce4Co8 cuboctahedra. Both Co(4)-Co(4) bond lengths are 2.44 Å. In the seventh Co site, Co(4) is bonded to four equivalent Ce(1); two equivalent Co(2); two equivalent Co(3); and four Co(4,4) atoms to form CoCe4Co8 cuboctahedra that share corners with four equivalent Co(4)Ce4Co8 cuboctahedra; corners with twelve equivalent Co(5)Ce5Co7 cuboctahedra; edges with two equivalent Co(4)Ce4Co8 cuboctahedra; edges with eight equivalent Co(5)Ce5Co7 cuboctahedra; faces with two equivalent Co(5)Ce5Co7 cuboctahedra; and faces with eight Co(4,4)Ce4Co8 cuboctahedra. In the eighth Co site, Co(5) is bonded to two equivalent Ce(1), three equivalent Ce(2), one Co(1), one Co(2), one Co(3), and four equivalent Co(5) atoms to form distorted CoCe5Co7 cuboctahedra that share corners with two equivalent Co(1)Ce6Co6 cuboctahedra; corners with six Co(4,4,4)Ce4Co8 cuboctahedra; corners with nine equivalent Co(5)Ce5Co7 cuboctahedra; edges with four Co(4,4)Ce4Co8 cuboctahedra; edges with four equivalent Co(5)Ce5Co7 cuboctahedra;  a faceface with one Co(4)Ce4Co8 cuboctahedra; faces with three equivalent Co(1)Ce6Co6 cuboctahedra; and faces with ten equivalent Co(5)Ce5Co7 cuboctahedra. All Co(5)-Co(5) bond lengths are 2.44 Å.