ThYCo10 crystallizes in the orthorhombic Pmmm space group. Th(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. Y(1) is bonded in a 18-coordinate geometry to two equivalent Co(2), four equivalent Co(1), four equivalent Co(3), and eight equivalent Co(5) atoms. There are five inequivalent Co sites. In the first Co site, Co(1) is bonded in a 9-coordinate geometry to one Th(1), two equivalent Y(1), two equivalent Co(3), and four equivalent Co(5) atoms. In the second Co site, Co(2) is bonded in a 9-coordinate geometry to two equivalent Th(1), one Y(1), two equivalent Co(4), and four equivalent Co(5) atoms. In the third Co site, Co(3) is bonded to four equivalent Y(1), four equivalent Co(1), and four equivalent Co(5) atoms to form CoY4Co8 cuboctahedra that share corners with four equivalent Co(4)Th4Co8 cuboctahedra, corners with four equivalent Co(3)Y4Co8 cuboctahedra, corners with eight equivalent Co(5)Y2Th2Co8 cuboctahedra, edges with two equivalent Co(3)Y4Co8 cuboctahedra, edges with eight equivalent Co(5)Y2Th2Co8 cuboctahedra, faces with two equivalent Co(3)Y4Co8 cuboctahedra, and faces with eight equivalent Co(5)Y2Th2Co8 cuboctahedra. In the fourth Co site, Co(4) is bonded to four equivalent Th(1), four equivalent Co(2), and four equivalent Co(5) atoms to form CoTh4Co8 cuboctahedra that share corners with four equivalent Co(4)Th4Co8 cuboctahedra, corners with four equivalent Co(3)Y4Co8 cuboctahedra, corners with eight equivalent Co(5)Y2Th2Co8 cuboctahedra, edges with two equivalent Co(4)Th4Co8 cuboctahedra, edges with eight equivalent Co(5)Y2Th2Co8 cuboctahedra, faces with two equivalent Co(4)Th4Co8 cuboctahedra, and faces with eight equivalent Co(5)Y2Th2Co8 cuboctahedra. In the fifth Co site, Co(5) is bonded to two equivalent Th(1), two equivalent Y(1), one Co(3), one Co(4), two equivalent Co(1), two equivalent Co(2), and two equivalent Co(5) atoms to form CoY2Th2Co8 cuboctahedra that share corners with two equivalent Co(4)Th4Co8 cuboctahedra, corners with two equivalent Co(3)Y4Co8 cuboctahedra, corners with twelve equivalent Co(5)Y2Th2Co8 cuboctahedra, edges with two equivalent Co(4)Th4Co8 cuboctahedra, edges with two equivalent Co(3)Y4Co8 cuboctahedra, edges with six equivalent Co(5)Y2Th2Co8 cuboctahedra, faces with two equivalent Co(4)Th4Co8 cuboctahedra, faces with two equivalent Co(3)Y4Co8 cuboctahedra, and faces with six equivalent Co(5)Y2Th2Co8 cuboctahedra.
ThYCo10 crystallizes in the orthorhombic Pmmm space group. Th(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 Th(1)-Co(1) bond lengths are 3.04 Å. All Th(1)-Co(2) bond lengths are 2.87 Å. All Th(1)-Co(4) bond lengths are 3.13 Å. All Th(1)-Co(5) bond lengths are 3.24 Å. Y(1) is bonded in a 18-coordinate geometry to two equivalent Co(2), four equivalent Co(1), four equivalent Co(3), and eight equivalent Co(5) atoms. Both Y(1)-Co(2) bond lengths are 2.92 Å. All Y(1)-Co(1) bond lengths are 2.81 Å. All Y(1)-Co(3) bond lengths are 3.13 Å. All Y(1)-Co(5) bond lengths are 3.14 Å. There are five inequivalent Co sites. In the first Co site, Co(1) is bonded in a 9-coordinate geometry to one Th(1), two equivalent Y(1), two equivalent Co(3), and four equivalent Co(5) atoms. Both Co(1)-Co(3) bond lengths are 2.39 Å. All Co(1)-Co(5) bond lengths are 2.44 Å. In the second Co site, Co(2) is bonded in a 9-coordinate geometry to two equivalent Th(1), one Y(1), two equivalent Co(4), and four equivalent Co(5) atoms. Both Co(2)-Co(4) bond lengths are 2.46 Å. All Co(2)-Co(5) bond lengths are 2.41 Å. In the third Co site, Co(3) is bonded to four equivalent Y(1), four equivalent Co(1), and four equivalent Co(5) atoms to form CoY4Co8 cuboctahedra that share corners with four equivalent Co(4)Th4Co8 cuboctahedra, corners with four equivalent Co(3)Y4Co8 cuboctahedra, corners with eight equivalent Co(5)Y2Th2Co8 cuboctahedra, edges with two equivalent Co(3)Y4Co8 cuboctahedra, edges with eight equivalent Co(5)Y2Th2Co8 cuboctahedra, faces with two equivalent Co(3)Y4Co8 cuboctahedra, and faces with eight equivalent Co(5)Y2Th2Co8 cuboctahedra. All Co(3)-Co(5) bond lengths are 2.49 Å. In the fourth Co site, Co(4) is bonded to four equivalent Th(1), four equivalent Co(2), and four equivalent Co(5) atoms to form CoTh4Co8 cuboctahedra that share corners with four equivalent Co(4)Th4Co8 cuboctahedra, corners with four equivalent Co(3)Y4Co8 cuboctahedra, corners with eight equivalent Co(5)Y2Th2Co8 cuboctahedra, edges with two equivalent Co(4)Th4Co8 cuboctahedra, edges with eight equivalent Co(5)Y2Th2Co8 cuboctahedra, faces with two equivalent Co(4)Th4Co8 cuboctahedra, and faces with eight equivalent Co(5)Y2Th2Co8 cuboctahedra. All Co(4)-Co(5) bond lengths are 2.56 Å. In the fifth Co site, Co(5) is bonded to two equivalent Th(1), two equivalent Y(1), one Co(3), one Co(4), two equivalent Co(1), two equivalent Co(2), and two equivalent Co(5) atoms to form CoY2Th2Co8 cuboctahedra that share corners with two equivalent Co(4)Th4Co8 cuboctahedra, corners with two equivalent Co(3)Y4Co8 cuboctahedra, corners with twelve equivalent Co(5)Y2Th2Co8 cuboctahedra, edges with two equivalent Co(4)Th4Co8 cuboctahedra, edges with two equivalent Co(3)Y4Co8 cuboctahedra, edges with six equivalent Co(5)Y2Th2Co8 cuboctahedra, faces with two equivalent Co(4)Th4Co8 cuboctahedra, faces with two equivalent Co(3)Y4Co8 cuboctahedra, and faces with six equivalent Co(5)Y2Th2Co8 cuboctahedra. There is one shorter (2.38 Å) and one longer (2.52 Å) Co(5)-Co(5) bond length.