Ce2Cd17 crystallizes in the hexagonal P-6m2 space group. There are four inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 18-coordinate geometry to six equivalent Cd(1), six equivalent Cd(2), and six equivalent Cd(5) atoms. In the second Ce site, Ce(2) is bonded in a 18-coordinate geometry to six equivalent Cd(1), six equivalent Cd(2), and six equivalent Cd(6) atoms. In the third Ce site, Ce(3) is bonded to two equivalent Cd(3), six equivalent Cd(1), six equivalent Cd(5), and six equivalent Cd(7) atoms to form distorted CeCd20 hexagonal bipyramids that share corners with six equivalent Ce(4)Cd20 hexagonal bipyramids, faces with six equivalent Cd(7)Ce2Cd10 cuboctahedra, faces with six equivalent Cd(1)Ce3Cd9 cuboctahedra, and faces with twelve equivalent Cd(2)Ce3Cd9 cuboctahedra. In the fourth Ce site, Ce(4) is bonded to two equivalent Cd(4), six equivalent Cd(2), six equivalent Cd(6), and six equivalent Cd(7) atoms to form distorted CeCd20 hexagonal bipyramids that share corners with six equivalent Ce(3)Cd20 hexagonal bipyramids, faces with six equivalent Cd(7)Ce2Cd10 cuboctahedra, faces with six equivalent Cd(2)Ce3Cd9 cuboctahedra, and faces with twelve equivalent Cd(1)Ce3Cd9 cuboctahedra. There are seven inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to one Ce(1), one Ce(2), one Ce(3), one Cd(3), two equivalent Cd(2), two equivalent Cd(5), two equivalent Cd(6), and two equivalent Cd(7) atoms to form distorted CdCe3Cd9 cuboctahedra that share corners with four equivalent Cd(2)Ce3Cd9 cuboctahedra, corners with five equivalent Cd(7)Ce2Cd10 cuboctahedra, corners with six equivalent Cd(1)Ce3Cd9 cuboctahedra, edges with three equivalent Cd(7)Ce2Cd10 cuboctahedra, edges with five equivalent Cd(2)Ce3Cd9 cuboctahedra, faces with two equivalent Cd(7)Ce2Cd10 cuboctahedra, faces with two equivalent Cd(2)Ce3Cd9 cuboctahedra, faces with six equivalent Cd(1)Ce3Cd9 cuboctahedra,  a faceface with one Ce(3)Cd20 hexagonal bipyramid, and faces with two equivalent Ce(4)Cd20 hexagonal bipyramids. In the second Cd site, Cd(2) is bonded to one Ce(1), one Ce(2), one Ce(4), one Cd(4), two equivalent Cd(1), two equivalent Cd(5), two equivalent Cd(6), and two equivalent Cd(7) atoms to form distorted CdCe3Cd9 cuboctahedra that share corners with four equivalent Cd(1)Ce3Cd9 cuboctahedra, corners with five equivalent Cd(7)Ce2Cd10 cuboctahedra, corners with six equivalent Cd(2)Ce3Cd9 cuboctahedra, edges with three equivalent Cd(7)Ce2Cd10 cuboctahedra, edges with five equivalent Cd(1)Ce3Cd9 cuboctahedra, faces with two equivalent Cd(7)Ce2Cd10 cuboctahedra, faces with two equivalent Cd(1)Ce3Cd9 cuboctahedra, faces with six equivalent Cd(2)Ce3Cd9 cuboctahedra,  a faceface with one Ce(4)Cd20 hexagonal bipyramid, and faces with two equivalent Ce(3)Cd20 hexagonal bipyramids. In the third Cd site, Cd(7) is bonded to one Ce(3), one Ce(4), one Cd(3), one Cd(4), two equivalent Cd(1), two equivalent Cd(2), two equivalent Cd(5), and two equivalent Cd(6) atoms to form CdCe2Cd10 cuboctahedra that share corners with four equivalent Cd(7)Ce2Cd10 cuboctahedra, corners with five equivalent Cd(1)Ce3Cd9 cuboctahedra, corners with five equivalent Cd(2)Ce3Cd9 cuboctahedra, edges with three equivalent Cd(1)Ce3Cd9 cuboctahedra, edges with three equivalent Cd(2)Ce3Cd9 cuboctahedra, faces with two equivalent Cd(1)Ce3Cd9 cuboctahedra, faces with two equivalent Cd(2)Ce3Cd9 cuboctahedra, faces with six equivalent Cd(7)Ce2Cd10 cuboctahedra,  a faceface with one Ce(3)Cd20 hexagonal bipyramid, and  a faceface with one Ce(4)Cd20 hexagonal bipyramid. In the fourth Cd site, Cd(3) is bonded in a 8-coordinate geometry to one Ce(3), one Cd(3), three equivalent Cd(1), and three equivalent Cd(7) atoms. In the fifth Cd site, Cd(4) is bonded in a 8-coordinate geometry to one Ce(4), one Cd(4), three equivalent Cd(2), and three equivalent Cd(7) atoms. In the sixth Cd site, Cd(5) is bonded in a 10-coordinate geometry to one Ce(1), one Ce(3), two equivalent Cd(1), two equivalent Cd(2), two equivalent Cd(5), and two equivalent Cd(7) atoms. In the seventh Cd site, Cd(6) is bonded in a 10-coordinate geometry to one Ce(2), one Ce(4), two equivalent Cd(1), two equivalent Cd(2), two equivalent Cd(6), and two equivalent Cd(7) atoms.
Ce2Cd17 crystallizes in the hexagonal P-6m2 space group. There are four inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 18-coordinate geometry to six equivalent Cd(1), six equivalent Cd(2), and six equivalent Cd(5) atoms. All Ce(1)-Cd(1) bond lengths are 3.89 Å. All Ce(1)-Cd(2) bond lengths are 3.96 Å. All Ce(1)-Cd(5) bond lengths are 3.55 Å. In the second Ce site, Ce(2) is bonded in a 18-coordinate geometry to six equivalent Cd(1), six equivalent Cd(2), and six equivalent Cd(6) atoms. All Ce(2)-Cd(1) bond lengths are 3.96 Å. All Ce(2)-Cd(2) bond lengths are 3.89 Å. All Ce(2)-Cd(6) bond lengths are 3.54 Å. In the third Ce site, Ce(3) is bonded to two equivalent Cd(3), six equivalent Cd(1), six equivalent Cd(5), and six equivalent Cd(7) atoms to form distorted CeCd20 hexagonal bipyramids that share corners with six equivalent Ce(4)Cd20 hexagonal bipyramids, faces with six equivalent Cd(7)Ce2Cd10 cuboctahedra, faces with six equivalent Cd(1)Ce3Cd9 cuboctahedra, and faces with twelve equivalent Cd(2)Ce3Cd9 cuboctahedra. Both Ce(3)-Cd(3) bond lengths are 3.58 Å. All Ce(3)-Cd(1) bond lengths are 4.03 Å. All Ce(3)-Cd(5) bond lengths are 3.58 Å. All Ce(3)-Cd(7) bond lengths are 3.99 Å. In the fourth Ce site, Ce(4) is bonded to two equivalent Cd(4), six equivalent Cd(2), six equivalent Cd(6), and six equivalent Cd(7) atoms to form distorted CeCd20 hexagonal bipyramids that share corners with six equivalent Ce(3)Cd20 hexagonal bipyramids, faces with six equivalent Cd(7)Ce2Cd10 cuboctahedra, faces with six equivalent Cd(2)Ce3Cd9 cuboctahedra, and faces with twelve equivalent Cd(1)Ce3Cd9 cuboctahedra. Both Ce(4)-Cd(4) bond lengths are 3.57 Å. All Ce(4)-Cd(2) bond lengths are 4.03 Å. All Ce(4)-Cd(6) bond lengths are 3.59 Å. All Ce(4)-Cd(7) bond lengths are 3.99 Å. There are seven inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to one Ce(1), one Ce(2), one Ce(3), one Cd(3), two equivalent Cd(2), two equivalent Cd(5), two equivalent Cd(6), and two equivalent Cd(7) atoms to form distorted CdCe3Cd9 cuboctahedra that share corners with four equivalent Cd(2)Ce3Cd9 cuboctahedra, corners with five equivalent Cd(7)Ce2Cd10 cuboctahedra, corners with six equivalent Cd(1)Ce3Cd9 cuboctahedra, edges with three equivalent Cd(7)Ce2Cd10 cuboctahedra, edges with five equivalent Cd(2)Ce3Cd9 cuboctahedra, faces with two equivalent Cd(7)Ce2Cd10 cuboctahedra, faces with two equivalent Cd(2)Ce3Cd9 cuboctahedra, faces with six equivalent Cd(1)Ce3Cd9 cuboctahedra,  a faceface with one Ce(3)Cd20 hexagonal bipyramid, and faces with two equivalent Ce(4)Cd20 hexagonal bipyramids. The Cd(1)-Cd(3) bond length is 3.32 Å. Both Cd(1)-Cd(2) bond lengths are 2.97 Å. Both Cd(1)-Cd(5) bond lengths are 3.12 Å. Both Cd(1)-Cd(6) bond lengths are 3.12 Å. Both Cd(1)-Cd(7) bond lengths are 3.10 Å. In the second Cd site, Cd(2) is bonded to one Ce(1), one Ce(2), one Ce(4), one Cd(4), two equivalent Cd(1), two equivalent Cd(5), two equivalent Cd(6), and two equivalent Cd(7) atoms to form distorted CdCe3Cd9 cuboctahedra that share corners with four equivalent Cd(1)Ce3Cd9 cuboctahedra, corners with five equivalent Cd(7)Ce2Cd10 cuboctahedra, corners with six equivalent Cd(2)Ce3Cd9 cuboctahedra, edges with three equivalent Cd(7)Ce2Cd10 cuboctahedra, edges with five equivalent Cd(1)Ce3Cd9 cuboctahedra, faces with two equivalent Cd(7)Ce2Cd10 cuboctahedra, faces with two equivalent Cd(1)Ce3Cd9 cuboctahedra, faces with six equivalent Cd(2)Ce3Cd9 cuboctahedra,  a faceface with one Ce(4)Cd20 hexagonal bipyramid, and faces with two equivalent Ce(3)Cd20 hexagonal bipyramids. The Cd(2)-Cd(4) bond length is 3.32 Å. Both Cd(2)-Cd(5) bond lengths are 3.13 Å. Both Cd(2)-Cd(6) bond lengths are 3.11 Å. Both Cd(2)-Cd(7) bond lengths are 3.10 Å. In the third Cd site, Cd(7) is bonded to one Ce(3), one Ce(4), one Cd(3), one Cd(4), two equivalent Cd(1), two equivalent Cd(2), two equivalent Cd(5), and two equivalent Cd(6) atoms to form CdCe2Cd10 cuboctahedra that share corners with four equivalent Cd(7)Ce2Cd10 cuboctahedra, corners with five equivalent Cd(1)Ce3Cd9 cuboctahedra, corners with five equivalent Cd(2)Ce3Cd9 cuboctahedra, edges with three equivalent Cd(1)Ce3Cd9 cuboctahedra, edges with three equivalent Cd(2)Ce3Cd9 cuboctahedra, faces with two equivalent Cd(1)Ce3Cd9 cuboctahedra, faces with two equivalent Cd(2)Ce3Cd9 cuboctahedra, faces with six equivalent Cd(7)Ce2Cd10 cuboctahedra,  a faceface with one Ce(3)Cd20 hexagonal bipyramid, and  a faceface with one Ce(4)Cd20 hexagonal bipyramid. The Cd(7)-Cd(3) bond length is 3.22 Å. The Cd(7)-Cd(4) bond length is 3.22 Å. Both Cd(7)-Cd(5) bond lengths are 3.10 Å. Both Cd(7)-Cd(6) bond lengths are 3.11 Å. In the fourth Cd site, Cd(3) is bonded in a 8-coordinate geometry to one Ce(3), one Cd(3), three equivalent Cd(1), and three equivalent Cd(7) atoms. The Cd(3)-Cd(3) bond length is 3.11 Å. In the fifth Cd site, Cd(4) is bonded in a 8-coordinate geometry to one Ce(4), one Cd(4), three equivalent Cd(2), and three equivalent Cd(7) atoms. The Cd(4)-Cd(4) bond length is 3.12 Å. In the sixth Cd site, Cd(5) is bonded in a 10-coordinate geometry to one Ce(1), one Ce(3), two equivalent Cd(1), two equivalent Cd(2), two equivalent Cd(5), and two equivalent Cd(7) atoms. There is one shorter (3.43 Å) and one longer (3.49 Å) Cd(5)-Cd(5) bond length. In the seventh Cd site, Cd(6) is bonded in a 10-coordinate geometry to one Ce(2), one Ce(4), two equivalent Cd(1), two equivalent Cd(2), two equivalent Cd(6), and two equivalent Cd(7) atoms. There is one shorter (3.42 Å) and one longer (3.51 Å) Cd(6)-Cd(6) bond length.