Ce2Fe17 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 18-coordinate geometry to six equivalent Fe(3) and twelve equivalent Fe(4) atoms. In the second Ce site, Ce(2) is bonded in a 20-coordinate geometry to two equivalent Fe(1), six equivalent Fe(2), six equivalent Fe(3), and six equivalent Fe(4) atoms. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 14-coordinate geometry to one Ce(2), one Fe(1), three equivalent Fe(2), three equivalent Fe(4), and six equivalent Fe(3) atoms. In the second Fe site, Fe(2) is bonded to two equivalent Ce(2), two equivalent Fe(1), four equivalent Fe(3), and four equivalent Fe(4) atoms to form FeCe2Fe10 cuboctahedra that share corners with four equivalent Fe(2)Ce2Fe10 cuboctahedra, corners with ten equivalent Fe(4)Ce3Fe9 cuboctahedra, edges with six equivalent Fe(4)Ce3Fe9 cuboctahedra, faces with four equivalent Fe(4)Ce3Fe9 cuboctahedra, and faces with six equivalent Fe(2)Ce2Fe10 cuboctahedra. In the third Fe site, Fe(3) is bonded in a 12-coordinate geometry to one Ce(1), one Ce(2), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(3), and four equivalent Fe(4) atoms. In the fourth Fe site, Fe(4) is bonded to one Ce(2), two equivalent Ce(1), one Fe(1), two equivalent Fe(2), two equivalent Fe(4), and four equivalent Fe(3) atoms to form FeCe3Fe9 cuboctahedra that share corners with five equivalent Fe(2)Ce2Fe10 cuboctahedra, corners with ten equivalent Fe(4)Ce3Fe9 cuboctahedra, edges with three equivalent Fe(2)Ce2Fe10 cuboctahedra, edges with five equivalent Fe(4)Ce3Fe9 cuboctahedra, faces with two equivalent Fe(2)Ce2Fe10 cuboctahedra, and faces with eight equivalent Fe(4)Ce3Fe9 cuboctahedra.
Ce2Fe17 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 18-coordinate geometry to six equivalent Fe(3) and twelve equivalent Fe(4) atoms. All Ce(1)-Fe(3) bond lengths are 3.01 Å. There are six shorter (3.17 Å) and six longer (3.31 Å) Ce(1)-Fe(4) bond lengths. In the second Ce site, Ce(2) is bonded in a 20-coordinate geometry to two equivalent Fe(1), six equivalent Fe(2), six equivalent Fe(3), and six equivalent Fe(4) atoms. Both Ce(2)-Fe(1) bond lengths are 3.01 Å. All Ce(2)-Fe(2) bond lengths are 3.24 Å. All Ce(2)-Fe(3) bond lengths are 3.05 Å. All Ce(2)-Fe(4) bond lengths are 3.16 Å. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 14-coordinate geometry to one Ce(2), one Fe(1), three equivalent Fe(2), three equivalent Fe(4), and six equivalent Fe(3) atoms. The Fe(1)-Fe(1) bond length is 2.39 Å. All Fe(1)-Fe(2) bond lengths are 2.62 Å. All Fe(1)-Fe(4) bond lengths are 2.66 Å. All Fe(1)-Fe(3) bond lengths are 2.77 Å. In the second Fe site, Fe(2) is bonded to two equivalent Ce(2), two equivalent Fe(1), four equivalent Fe(3), and four equivalent Fe(4) atoms to form FeCe2Fe10 cuboctahedra that share corners with four equivalent Fe(2)Ce2Fe10 cuboctahedra, corners with ten equivalent Fe(4)Ce3Fe9 cuboctahedra, edges with six equivalent Fe(4)Ce3Fe9 cuboctahedra, faces with four equivalent Fe(4)Ce3Fe9 cuboctahedra, and faces with six equivalent Fe(2)Ce2Fe10 cuboctahedra. All Fe(2)-Fe(3) bond lengths are 2.47 Å. All Fe(2)-Fe(4) bond lengths are 2.46 Å. In the third Fe site, Fe(3) is bonded in a 12-coordinate geometry to one Ce(1), one Ce(2), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(3), and four equivalent Fe(4) atoms. There is one shorter (2.45 Å) and one longer (2.54 Å) Fe(3)-Fe(3) bond length. There are two shorter (2.54 Å) and two longer (2.67 Å) Fe(3)-Fe(4) bond lengths. In the fourth Fe site, Fe(4) is bonded to one Ce(2), two equivalent Ce(1), one Fe(1), two equivalent Fe(2), two equivalent Fe(4), and four equivalent Fe(3) atoms to form FeCe3Fe9 cuboctahedra that share corners with five equivalent Fe(2)Ce2Fe10 cuboctahedra, corners with ten equivalent Fe(4)Ce3Fe9 cuboctahedra, edges with three equivalent Fe(2)Ce2Fe10 cuboctahedra, edges with five equivalent Fe(4)Ce3Fe9 cuboctahedra, faces with two equivalent Fe(2)Ce2Fe10 cuboctahedra, and faces with eight equivalent Fe(4)Ce3Fe9 cuboctahedra. Both Fe(4)-Fe(4) bond lengths are 2.48 Å.