UNdCo10 crystallizes in the orthorhombic Pmmm space group. U(1) is bonded in a distorted hexagonal planar geometry to two equivalent Co(2), four equivalent Co(1), four equivalent Co(3), and eight equivalent Co(5) atoms. Nd(1) is bonded in a 18-coordinate geometry to two equivalent Co(1), four equivalent Co(2), four equivalent Co(4), and eight equivalent Co(5) atoms. There are five inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent U(1), one Nd(1), one Co(1), two equivalent Co(2), two equivalent Co(3), and four equivalent Co(5) atoms to form distorted CoNdU2Co9 cuboctahedra that share corners with four equivalent Co(3)U4Co8 cuboctahedra, corners with five equivalent Co(1)NdU2Co9 cuboctahedra, corners with eight equivalent Co(5)Nd2U2Co8 cuboctahedra, edges with two equivalent Co(1)NdU2Co9 cuboctahedra, faces with two equivalent Co(3)U4Co8 cuboctahedra, faces with three equivalent Co(1)NdU2Co9 cuboctahedra, faces with four equivalent Co(4)Nd4Co8 cuboctahedra, and faces with twelve equivalent Co(5)Nd2U2Co8 cuboctahedra. In the second Co site, Co(2) is bonded in a 11-coordinate geometry to one U(1), two equivalent Nd(1), two equivalent Co(1), two equivalent Co(4), and four equivalent Co(5) atoms. In the third Co site, Co(3) is bonded to four equivalent U(1), four equivalent Co(1), and four equivalent Co(5) atoms to form CoU4Co8 cuboctahedra that share corners with four equivalent Co(4)Nd4Co8 cuboctahedra, corners with four equivalent Co(3)U4Co8 cuboctahedra, corners with eight equivalent Co(5)Nd2U2Co8 cuboctahedra, corners with eight equivalent Co(1)NdU2Co9 cuboctahedra, edges with two equivalent Co(3)U4Co8 cuboctahedra, edges with eight equivalent Co(5)Nd2U2Co8 cuboctahedra, faces with two equivalent Co(3)U4Co8 cuboctahedra, faces with four equivalent Co(1)NdU2Co9 cuboctahedra, and faces with eight equivalent Co(5)Nd2U2Co8 cuboctahedra. In the fourth Co site, Co(4) is bonded to four equivalent Nd(1), four equivalent Co(2), and four equivalent Co(5) atoms to form CoNd4Co8 cuboctahedra that share corners with four equivalent Co(4)Nd4Co8 cuboctahedra, corners with four equivalent Co(3)U4Co8 cuboctahedra, corners with eight equivalent Co(5)Nd2U2Co8 cuboctahedra, edges with two equivalent Co(4)Nd4Co8 cuboctahedra, edges with eight equivalent Co(5)Nd2U2Co8 cuboctahedra, faces with two equivalent Co(4)Nd4Co8 cuboctahedra, faces with eight equivalent Co(5)Nd2U2Co8 cuboctahedra, and faces with eight equivalent Co(1)NdU2Co9 cuboctahedra. In the fifth Co site, Co(5) is bonded to two equivalent U(1), two equivalent Nd(1), one Co(3), one Co(4), two equivalent Co(1), two equivalent Co(2), and two equivalent Co(5) atoms to form CoNd2U2Co8 cuboctahedra that share corners with two equivalent Co(4)Nd4Co8 cuboctahedra, corners with two equivalent Co(3)U4Co8 cuboctahedra, corners with four equivalent Co(1)NdU2Co9 cuboctahedra, corners with twelve equivalent Co(5)Nd2U2Co8 cuboctahedra, edges with two equivalent Co(4)Nd4Co8 cuboctahedra, edges with two equivalent Co(3)U4Co8 cuboctahedra, edges with six equivalent Co(5)Nd2U2Co8 cuboctahedra, faces with two equivalent Co(4)Nd4Co8 cuboctahedra, faces with two equivalent Co(3)U4Co8 cuboctahedra, faces with six equivalent Co(5)Nd2U2Co8 cuboctahedra, and faces with six equivalent Co(1)NdU2Co9 cuboctahedra.
UNdCo10 crystallizes in the orthorhombic Pmmm space group. U(1) is bonded in a distorted hexagonal planar geometry to two equivalent Co(2), four equivalent Co(1), four equivalent Co(3), and eight equivalent Co(5) atoms. Both U(1)-Co(2) bond lengths are 2.55 Å. All U(1)-Co(1) bond lengths are 2.71 Å. All U(1)-Co(3) bond lengths are 3.10 Å. All U(1)-Co(5) bond lengths are 3.05 Å. Nd(1) is bonded in a 18-coordinate geometry to two equivalent Co(1), four equivalent Co(2), four equivalent Co(4), and eight equivalent Co(5) atoms. Both Nd(1)-Co(1) bond lengths are 2.91 Å. All Nd(1)-Co(2) bond lengths are 2.89 Å. All Nd(1)-Co(4) bond lengths are 3.10 Å. All Nd(1)-Co(5) bond lengths are 3.15 Å. There are five inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent U(1), one Nd(1), one Co(1), two equivalent Co(2), two equivalent Co(3), and four equivalent Co(5) atoms to form distorted CoNdU2Co9 cuboctahedra that share corners with four equivalent Co(3)U4Co8 cuboctahedra, corners with five equivalent Co(1)NdU2Co9 cuboctahedra, corners with eight equivalent Co(5)Nd2U2Co8 cuboctahedra, edges with two equivalent Co(1)NdU2Co9 cuboctahedra, faces with two equivalent Co(3)U4Co8 cuboctahedra, faces with three equivalent Co(1)NdU2Co9 cuboctahedra, faces with four equivalent Co(4)Nd4Co8 cuboctahedra, and faces with twelve equivalent Co(5)Nd2U2Co8 cuboctahedra. The Co(1)-Co(1) bond length is 2.50 Å. Both Co(1)-Co(2) bond lengths are 2.73 Å. Both Co(1)-Co(3) bond lengths are 2.33 Å. All Co(1)-Co(5) bond lengths are 2.43 Å. In the second Co site, Co(2) is bonded in a 11-coordinate geometry to one U(1), two equivalent Nd(1), two equivalent Co(1), two equivalent Co(4), and four equivalent Co(5) atoms. Both Co(2)-Co(4) bond lengths are 2.54 Å. All Co(2)-Co(5) bond lengths are 2.36 Å. In the third Co site, Co(3) is bonded to four equivalent U(1), four equivalent Co(1), and four equivalent Co(5) atoms to form CoU4Co8 cuboctahedra that share corners with four equivalent Co(4)Nd4Co8 cuboctahedra, corners with four equivalent Co(3)U4Co8 cuboctahedra, corners with eight equivalent Co(5)Nd2U2Co8 cuboctahedra, corners with eight equivalent Co(1)NdU2Co9 cuboctahedra, edges with two equivalent Co(3)U4Co8 cuboctahedra, edges with eight equivalent Co(5)Nd2U2Co8 cuboctahedra, faces with two equivalent Co(3)U4Co8 cuboctahedra, faces with four equivalent Co(1)NdU2Co9 cuboctahedra, and faces with eight equivalent Co(5)Nd2U2Co8 cuboctahedra. All Co(3)-Co(5) bond lengths are 2.35 Å. In the fourth Co site, Co(4) is bonded to four equivalent Nd(1), four equivalent Co(2), and four equivalent Co(5) atoms to form CoNd4Co8 cuboctahedra that share corners with four equivalent Co(4)Nd4Co8 cuboctahedra, corners with four equivalent Co(3)U4Co8 cuboctahedra, corners with eight equivalent Co(5)Nd2U2Co8 cuboctahedra, edges with two equivalent Co(4)Nd4Co8 cuboctahedra, edges with eight equivalent Co(5)Nd2U2Co8 cuboctahedra, faces with two equivalent Co(4)Nd4Co8 cuboctahedra, faces with eight equivalent Co(5)Nd2U2Co8 cuboctahedra, and faces with eight equivalent Co(1)NdU2Co9 cuboctahedra. All Co(4)-Co(5) bond lengths are 2.45 Å. In the fifth Co site, Co(5) is bonded to two equivalent U(1), two equivalent Nd(1), one Co(3), one Co(4), two equivalent Co(1), two equivalent Co(2), and two equivalent Co(5) atoms to form CoNd2U2Co8 cuboctahedra that share corners with two equivalent Co(4)Nd4Co8 cuboctahedra, corners with two equivalent Co(3)U4Co8 cuboctahedra, corners with four equivalent Co(1)NdU2Co9 cuboctahedra, corners with twelve equivalent Co(5)Nd2U2Co8 cuboctahedra, edges with two equivalent Co(4)Nd4Co8 cuboctahedra, edges with two equivalent Co(3)U4Co8 cuboctahedra, edges with six equivalent Co(5)Nd2U2Co8 cuboctahedra, faces with two equivalent Co(4)Nd4Co8 cuboctahedra, faces with two equivalent Co(3)U4Co8 cuboctahedra, faces with six equivalent Co(5)Nd2U2Co8 cuboctahedra, and faces with six equivalent Co(1)NdU2Co9 cuboctahedra. There is one shorter (2.37 Å) and one longer (2.43 Å) Co(5)-Co(5) bond length.