Pu2Co17 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Pu sites. In the first Pu site, Pu(1) is bonded in a 18-coordinate geometry to six equivalent Co(1) and twelve equivalent Co(3) atoms. In the second Pu site, Pu(2) is bonded in a 20-coordinate geometry to two equivalent Co(4), six equivalent Co(1), six equivalent Co(2), and six equivalent Co(3) atoms. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded in a 12-coordinate geometry to one Pu(1), one Pu(2), two equivalent Co(1), two equivalent Co(2), two equivalent Co(4), and four equivalent Co(3) atoms. In the second Co site, Co(2) is bonded to two equivalent Pu(2), two equivalent Co(4), four equivalent Co(1), and four equivalent Co(3) atoms to form CoPu2Co10 cuboctahedra that share corners with four equivalent Co(2)Pu2Co10 cuboctahedra, corners with ten equivalent Co(3)Pu3Co9 cuboctahedra, edges with six equivalent Co(3)Pu3Co9 cuboctahedra, faces with four equivalent Co(3)Pu3Co9 cuboctahedra, and faces with six equivalent Co(2)Pu2Co10 cuboctahedra. In the third Co site, Co(3) is bonded to one Pu(2), two equivalent Pu(1), one Co(4), two equivalent Co(2), two equivalent Co(3), and four equivalent Co(1) atoms to form distorted CoPu3Co9 cuboctahedra that share corners with five equivalent Co(2)Pu2Co10 cuboctahedra, corners with ten equivalent Co(3)Pu3Co9 cuboctahedra, edges with three equivalent Co(2)Pu2Co10 cuboctahedra, edges with five equivalent Co(3)Pu3Co9 cuboctahedra, faces with two equivalent Co(2)Pu2Co10 cuboctahedra, and faces with eight equivalent Co(3)Pu3Co9 cuboctahedra. In the fourth Co site, Co(4) is bonded in a 14-coordinate geometry to one Pu(2), one Co(4), three equivalent Co(2), three equivalent Co(3), and six equivalent Co(1) atoms.
Pu2Co17 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Pu sites. In the first Pu site, Pu(1) is bonded in a 18-coordinate geometry to six equivalent Co(1) and twelve equivalent Co(3) atoms. All Pu(1)-Co(1) bond lengths are 2.93 Å. There are six shorter (3.03 Å) and six longer (3.27 Å) Pu(1)-Co(3) bond lengths. In the second Pu site, Pu(2) is bonded in a 20-coordinate geometry to two equivalent Co(4), six equivalent Co(1), six equivalent Co(2), and six equivalent Co(3) atoms. Both Pu(2)-Co(4) bond lengths are 2.87 Å. All Pu(2)-Co(1) bond lengths are 2.98 Å. All Pu(2)-Co(2) bond lengths are 3.13 Å. All Pu(2)-Co(3) bond lengths are 3.00 Å. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded in a 12-coordinate geometry to one Pu(1), one Pu(2), two equivalent Co(1), two equivalent Co(2), two equivalent Co(4), and four equivalent Co(3) atoms. There is one shorter (2.36 Å) and one longer (2.46 Å) Co(1)-Co(1) bond length. Both Co(1)-Co(2) bond lengths are 2.39 Å. Both Co(1)-Co(4) bond lengths are 2.68 Å. All Co(1)-Co(3) bond lengths are 2.52 Å. In the second Co site, Co(2) is bonded to two equivalent Pu(2), two equivalent Co(4), four equivalent Co(1), and four equivalent Co(3) atoms to form CoPu2Co10 cuboctahedra that share corners with four equivalent Co(2)Pu2Co10 cuboctahedra, corners with ten equivalent Co(3)Pu3Co9 cuboctahedra, edges with six equivalent Co(3)Pu3Co9 cuboctahedra, faces with four equivalent Co(3)Pu3Co9 cuboctahedra, and faces with six equivalent Co(2)Pu2Co10 cuboctahedra. Both Co(2)-Co(4) bond lengths are 2.54 Å. All Co(2)-Co(3) bond lengths are 2.39 Å. In the third Co site, Co(3) is bonded to one Pu(2), two equivalent Pu(1), one Co(4), two equivalent Co(2), two equivalent Co(3), and four equivalent Co(1) atoms to form distorted CoPu3Co9 cuboctahedra that share corners with five equivalent Co(2)Pu2Co10 cuboctahedra, corners with ten equivalent Co(3)Pu3Co9 cuboctahedra, edges with three equivalent Co(2)Pu2Co10 cuboctahedra, edges with five equivalent Co(3)Pu3Co9 cuboctahedra, faces with two equivalent Co(2)Pu2Co10 cuboctahedra, and faces with eight equivalent Co(3)Pu3Co9 cuboctahedra. The Co(3)-Co(4) bond length is 2.59 Å. Both Co(3)-Co(3) bond lengths are 2.44 Å. In the fourth Co site, Co(4) is bonded in a 14-coordinate geometry to one Pu(2), one Co(4), three equivalent Co(2), three equivalent Co(3), and six equivalent Co(1) atoms. The Co(4)-Co(4) bond length is 2.35 Å.