Ce2Mn17C2 crystallizes in the monoclinic C2/m space group. Ce(1) is bonded in a distorted bent 120 degrees geometry to one Mn(1), one Mn(6), two equivalent Mn(2), two equivalent Mn(7), three equivalent Mn(5), and two equivalent C(1) atoms. There are seven inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 14-coordinate geometry to one Ce(1), one Mn(1), one Mn(5), one Mn(6), two equivalent Mn(2), two equivalent Mn(4), two equivalent Mn(7), and four equivalent Mn(3) atoms. In the second Mn site, Mn(2) is bonded to two equivalent Ce(1), two equivalent Mn(1), two equivalent Mn(3), two equivalent Mn(4), two equivalent Mn(5), and two equivalent Mn(7) atoms to form distorted MnCe2Mn10 cuboctahedra that share corners with two equivalent Mn(2)Ce2Mn10 cuboctahedra, corners with two equivalent Mn(6)Ce2Mn10 cuboctahedra, corners with two equivalent Mn(7)Ce2Mn10 cuboctahedra, corners with two equivalent Mn(5)Ce3Mn9 cuboctahedra, corners with four equivalent C(1)Ce2Mn4 octahedra,  an edgeedge with one Mn(2)Ce2Mn10 cuboctahedra, edges with two equivalent Mn(7)Ce2Mn10 cuboctahedra, edges with two equivalent C(1)Ce2Mn4 octahedra,  a faceface with one Mn(2)Ce2Mn10 cuboctahedra, faces with two equivalent Mn(6)Ce2Mn10 cuboctahedra, faces with two equivalent Mn(7)Ce2Mn10 cuboctahedra, and faces with four equivalent Mn(5)Ce3Mn9 cuboctahedra. The corner-sharing octahedral tilt angles range from 21-28°. In the third Mn site, Mn(3) is bonded in a single-bond geometry to one Mn(2), one Mn(5), one Mn(6), one Mn(7), two equivalent Mn(1), and one C(1) atom. In the fourth Mn site, Mn(4) is bonded in a single-bond geometry to one Mn(1), one Mn(2), one Mn(5), one Mn(6), one Mn(7), and one C(1) atom. In the fifth Mn site, Mn(5) is bonded to three equivalent Ce(1), one Mn(1), two equivalent Mn(2), two equivalent Mn(3), two equivalent Mn(4), and two equivalent Mn(7) atoms to form distorted MnCe3Mn9 cuboctahedra that share corners with two equivalent Mn(2)Ce2Mn10 cuboctahedra, corners with two equivalent Mn(7)Ce2Mn10 cuboctahedra, corners with three equivalent Mn(6)Ce2Mn10 cuboctahedra, corners with four equivalent Mn(5)Ce3Mn9 cuboctahedra, corners with four equivalent C(1)Ce2Mn4 octahedra,  an edgeedge with one Mn(6)Ce2Mn10 cuboctahedra,  an edgeedge with one Mn(5)Ce3Mn9 cuboctahedra, edges with two equivalent Mn(7)Ce2Mn10 cuboctahedra,  a faceface with one Mn(6)Ce2Mn10 cuboctahedra,  a faceface with one Mn(5)Ce3Mn9 cuboctahedra, faces with two equivalent Mn(7)Ce2Mn10 cuboctahedra, faces with four equivalent Mn(2)Ce2Mn10 cuboctahedra, and faces with two equivalent C(1)Ce2Mn4 octahedra. The corner-sharing octahedral tilt angles range from 61-70°. In the sixth Mn site, Mn(6) is bonded to two equivalent Ce(1), two equivalent Mn(1), four equivalent Mn(3), and four equivalent Mn(4) atoms to form distorted MnCe2Mn10 cuboctahedra that share corners with four equivalent Mn(2)Ce2Mn10 cuboctahedra, corners with four equivalent Mn(7)Ce2Mn10 cuboctahedra, corners with six equivalent Mn(5)Ce3Mn9 cuboctahedra, edges with two equivalent Mn(5)Ce3Mn9 cuboctahedra, faces with two equivalent Mn(5)Ce3Mn9 cuboctahedra, faces with four equivalent Mn(2)Ce2Mn10 cuboctahedra, faces with four equivalent Mn(7)Ce2Mn10 cuboctahedra, and faces with four equivalent C(1)Ce2Mn4 octahedra. In the seventh Mn site, Mn(7) is bonded to two equivalent Ce(1), two equivalent Mn(1), two equivalent Mn(2), two equivalent Mn(3), two equivalent Mn(4), and two equivalent Mn(5) atoms to form distorted MnCe2Mn10 cuboctahedra that share corners with two equivalent Mn(2)Ce2Mn10 cuboctahedra, corners with two equivalent Mn(6)Ce2Mn10 cuboctahedra, corners with two equivalent Mn(7)Ce2Mn10 cuboctahedra, corners with two equivalent Mn(5)Ce3Mn9 cuboctahedra, corners with two equivalent C(1)Ce2Mn4 octahedra, edges with two equivalent Mn(2)Ce2Mn10 cuboctahedra, edges with two equivalent Mn(5)Ce3Mn9 cuboctahedra, faces with two equivalent Mn(2)Ce2Mn10 cuboctahedra, faces with two equivalent Mn(6)Ce2Mn10 cuboctahedra, faces with two equivalent Mn(7)Ce2Mn10 cuboctahedra, faces with two equivalent Mn(5)Ce3Mn9 cuboctahedra, and faces with two equivalent C(1)Ce2Mn4 octahedra. The corner-sharing octahedral tilt angles are 47°. C(1) is bonded to two equivalent Ce(1), two equivalent Mn(3), and two equivalent Mn(4) atoms to form CCe2Mn4 octahedra that share corners with two equivalent Mn(7)Ce2Mn10 cuboctahedra, corners with four equivalent Mn(2)Ce2Mn10 cuboctahedra, corners with four equivalent Mn(5)Ce3Mn9 cuboctahedra, corners with two equivalent C(1)Ce2Mn4 octahedra, edges with two equivalent Mn(2)Ce2Mn10 cuboctahedra, faces with two equivalent Mn(6)Ce2Mn10 cuboctahedra, faces with two equivalent Mn(7)Ce2Mn10 cuboctahedra, and faces with two equivalent Mn(5)Ce3Mn9 cuboctahedra. The corner-sharing octahedral tilt angles are 63°.
Ce2Mn17C2 crystallizes in the monoclinic C2/m space group. Ce(1) is bonded in a distorted bent 120 degrees geometry to one Mn(1), one Mn(6), two equivalent Mn(2), two equivalent Mn(7), three equivalent Mn(5), and two equivalent C(1) atoms. The Ce(1)-Mn(1) bond length is 3.11 Å. The Ce(1)-Mn(6) bond length is 3.38 Å. Both Ce(1)-Mn(2) bond lengths are 3.11 Å. Both Ce(1)-Mn(7) bond lengths are 3.34 Å. There are a spread of Ce(1)-Mn(5) bond distances ranging from 2.91-3.36 Å. Both Ce(1)-C(1) bond lengths are 2.53 Å. There are seven inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 14-coordinate geometry to one Ce(1), one Mn(1), one Mn(5), one Mn(6), two equivalent Mn(2), two equivalent Mn(4), two equivalent Mn(7), and four equivalent Mn(3) atoms. The Mn(1)-Mn(1) bond length is 2.37 Å. The Mn(1)-Mn(5) bond length is 2.64 Å. The Mn(1)-Mn(6) bond length is 2.61 Å. Both Mn(1)-Mn(2) bond lengths are 2.62 Å. Both Mn(1)-Mn(4) bond lengths are 2.59 Å. Both Mn(1)-Mn(7) bond lengths are 2.63 Å. There are two shorter (2.66 Å) and two longer (2.67 Å) Mn(1)-Mn(3) bond lengths. In the second Mn site, Mn(2) is bonded to two equivalent Ce(1), two equivalent Mn(1), two equivalent Mn(3), two equivalent Mn(4), two equivalent Mn(5), and two equivalent Mn(7) atoms to form distorted MnCe2Mn10 cuboctahedra that share corners with two equivalent Mn(2)Ce2Mn10 cuboctahedra, corners with two equivalent Mn(6)Ce2Mn10 cuboctahedra, corners with two equivalent Mn(7)Ce2Mn10 cuboctahedra, corners with two equivalent Mn(5)Ce3Mn9 cuboctahedra, corners with four equivalent C(1)Ce2Mn4 octahedra,  an edgeedge with one Mn(2)Ce2Mn10 cuboctahedra, edges with two equivalent Mn(7)Ce2Mn10 cuboctahedra, edges with two equivalent C(1)Ce2Mn4 octahedra,  a faceface with one Mn(2)Ce2Mn10 cuboctahedra, faces with two equivalent Mn(6)Ce2Mn10 cuboctahedra, faces with two equivalent Mn(7)Ce2Mn10 cuboctahedra, and faces with four equivalent Mn(5)Ce3Mn9 cuboctahedra. The corner-sharing octahedral tilt angles range from 21-28°. Both Mn(2)-Mn(3) bond lengths are 2.37 Å. Both Mn(2)-Mn(4) bond lengths are 2.53 Å. Both Mn(2)-Mn(5) bond lengths are 2.66 Å. Both Mn(2)-Mn(7) bond lengths are 2.38 Å. In the third Mn site, Mn(3) is bonded in a single-bond geometry to one Mn(2), one Mn(5), one Mn(6), one Mn(7), two equivalent Mn(1), and one C(1) atom. The Mn(3)-Mn(5) bond length is 2.60 Å. The Mn(3)-Mn(6) bond length is 2.41 Å. The Mn(3)-Mn(7) bond length is 2.41 Å. The Mn(3)-C(1) bond length is 1.90 Å. In the fourth Mn site, Mn(4) is bonded in a single-bond geometry to one Mn(1), one Mn(2), one Mn(5), one Mn(6), one Mn(7), and one C(1) atom. The Mn(4)-Mn(5) bond length is 2.62 Å. The Mn(4)-Mn(6) bond length is 2.43 Å. The Mn(4)-Mn(7) bond length is 2.43 Å. The Mn(4)-C(1) bond length is 1.88 Å. In the fifth Mn site, Mn(5) is bonded to three equivalent Ce(1), one Mn(1), two equivalent Mn(2), two equivalent Mn(3), two equivalent Mn(4), and two equivalent Mn(7) atoms to form distorted MnCe3Mn9 cuboctahedra that share corners with two equivalent Mn(2)Ce2Mn10 cuboctahedra, corners with two equivalent Mn(7)Ce2Mn10 cuboctahedra, corners with three equivalent Mn(6)Ce2Mn10 cuboctahedra, corners with four equivalent Mn(5)Ce3Mn9 cuboctahedra, corners with four equivalent C(1)Ce2Mn4 octahedra,  an edgeedge with one Mn(6)Ce2Mn10 cuboctahedra,  an edgeedge with one Mn(5)Ce3Mn9 cuboctahedra, edges with two equivalent Mn(7)Ce2Mn10 cuboctahedra,  a faceface with one Mn(6)Ce2Mn10 cuboctahedra,  a faceface with one Mn(5)Ce3Mn9 cuboctahedra, faces with two equivalent Mn(7)Ce2Mn10 cuboctahedra, faces with four equivalent Mn(2)Ce2Mn10 cuboctahedra, and faces with two equivalent C(1)Ce2Mn4 octahedra. The corner-sharing octahedral tilt angles range from 61-70°. Both Mn(5)-Mn(7) bond lengths are 2.46 Å. In the sixth Mn site, Mn(6) is bonded to two equivalent Ce(1), two equivalent Mn(1), four equivalent Mn(3), and four equivalent Mn(4) atoms to form distorted MnCe2Mn10 cuboctahedra that share corners with four equivalent Mn(2)Ce2Mn10 cuboctahedra, corners with four equivalent Mn(7)Ce2Mn10 cuboctahedra, corners with six equivalent Mn(5)Ce3Mn9 cuboctahedra, edges with two equivalent Mn(5)Ce3Mn9 cuboctahedra, faces with two equivalent Mn(5)Ce3Mn9 cuboctahedra, faces with four equivalent Mn(2)Ce2Mn10 cuboctahedra, faces with four equivalent Mn(7)Ce2Mn10 cuboctahedra, and faces with four equivalent C(1)Ce2Mn4 octahedra. In the seventh Mn site, Mn(7) is bonded to two equivalent Ce(1), two equivalent Mn(1), two equivalent Mn(2), two equivalent Mn(3), two equivalent Mn(4), and two equivalent Mn(5) atoms to form distorted MnCe2Mn10 cuboctahedra that share corners with two equivalent Mn(2)Ce2Mn10 cuboctahedra, corners with two equivalent Mn(6)Ce2Mn10 cuboctahedra, corners with two equivalent Mn(7)Ce2Mn10 cuboctahedra, corners with two equivalent Mn(5)Ce3Mn9 cuboctahedra, corners with two equivalent C(1)Ce2Mn4 octahedra, edges with two equivalent Mn(2)Ce2Mn10 cuboctahedra, edges with two equivalent Mn(5)Ce3Mn9 cuboctahedra, faces with two equivalent Mn(2)Ce2Mn10 cuboctahedra, faces with two equivalent Mn(6)Ce2Mn10 cuboctahedra, faces with two equivalent Mn(7)Ce2Mn10 cuboctahedra, faces with two equivalent Mn(5)Ce3Mn9 cuboctahedra, and faces with two equivalent C(1)Ce2Mn4 octahedra. The corner-sharing octahedral tilt angles are 47°. C(1) is bonded to two equivalent Ce(1), two equivalent Mn(3), and two equivalent Mn(4) atoms to form CCe2Mn4 octahedra that share corners with two equivalent Mn(7)Ce2Mn10 cuboctahedra, corners with four equivalent Mn(2)Ce2Mn10 cuboctahedra, corners with four equivalent Mn(5)Ce3Mn9 cuboctahedra, corners with two equivalent C(1)Ce2Mn4 octahedra, edges with two equivalent Mn(2)Ce2Mn10 cuboctahedra, faces with two equivalent Mn(6)Ce2Mn10 cuboctahedra, faces with two equivalent Mn(7)Ce2Mn10 cuboctahedra, and faces with two equivalent Mn(5)Ce3Mn9 cuboctahedra. The corner-sharing octahedral tilt angles are 63°.