ThTb3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. Th(1) is bonded to four equivalent Tb(2) and eight equivalent Tb(1) atoms to form ThTb12 cuboctahedra that share corners with four equivalent Th(1)Tb12 cuboctahedra, corners with eight equivalent Tb(2)Tb8Th4 cuboctahedra, edges with eight equivalent Th(1)Tb12 cuboctahedra, edges with sixteen equivalent Tb(1)Tb8Th4 cuboctahedra, faces with four equivalent Th(1)Tb12 cuboctahedra, faces with six equivalent Tb(2)Tb8Th4 cuboctahedra, and faces with eight equivalent Tb(1)Tb8Th4 cuboctahedra. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded to four equivalent Th(1), four equivalent Tb(1), and four equivalent Tb(2) atoms to form TbTb8Th4 cuboctahedra that share corners with twelve equivalent Tb(1)Tb8Th4 cuboctahedra, edges with eight equivalent Th(1)Tb12 cuboctahedra, edges with eight equivalent Tb(1)Tb8Th4 cuboctahedra, edges with eight equivalent Tb(2)Tb8Th4 cuboctahedra, faces with four equivalent Th(1)Tb12 cuboctahedra, faces with four equivalent Tb(2)Tb8Th4 cuboctahedra, and faces with ten equivalent Tb(1)Tb8Th4 cuboctahedra. In the second Tb site, Tb(2) is bonded to four equivalent Th(1) and eight equivalent Tb(1) atoms to form TbTb8Th4 cuboctahedra that share corners with four equivalent Tb(2)Tb8Th4 cuboctahedra, corners with eight equivalent Th(1)Tb12 cuboctahedra, edges with eight equivalent Tb(2)Tb8Th4 cuboctahedra, edges with sixteen equivalent Tb(1)Tb8Th4 cuboctahedra, faces with four equivalent Tb(2)Tb8Th4 cuboctahedra, faces with six equivalent Th(1)Tb12 cuboctahedra, and faces with eight equivalent Tb(1)Tb8Th4 cuboctahedra.
ThTb3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. Th(1) is bonded to four equivalent Tb(2) and eight equivalent Tb(1) atoms to form ThTb12 cuboctahedra that share corners with four equivalent Th(1)Tb12 cuboctahedra, corners with eight equivalent Tb(2)Tb8Th4 cuboctahedra, edges with eight equivalent Th(1)Tb12 cuboctahedra, edges with sixteen equivalent Tb(1)Tb8Th4 cuboctahedra, faces with four equivalent Th(1)Tb12 cuboctahedra, faces with six equivalent Tb(2)Tb8Th4 cuboctahedra, and faces with eight equivalent Tb(1)Tb8Th4 cuboctahedra. All Th(1)-Tb(2) bond lengths are 3.60 Å. All Th(1)-Tb(1) bond lengths are 3.56 Å. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded to four equivalent Th(1), four equivalent Tb(1), and four equivalent Tb(2) atoms to form TbTb8Th4 cuboctahedra that share corners with twelve equivalent Tb(1)Tb8Th4 cuboctahedra, edges with eight equivalent Th(1)Tb12 cuboctahedra, edges with eight equivalent Tb(1)Tb8Th4 cuboctahedra, edges with eight equivalent Tb(2)Tb8Th4 cuboctahedra, faces with four equivalent Th(1)Tb12 cuboctahedra, faces with four equivalent Tb(2)Tb8Th4 cuboctahedra, and faces with ten equivalent Tb(1)Tb8Th4 cuboctahedra. All Tb(1)-Tb(1) bond lengths are 3.60 Å. All Tb(1)-Tb(2) bond lengths are 3.56 Å. In the second Tb site, Tb(2) is bonded to four equivalent Th(1) and eight equivalent Tb(1) atoms to form TbTb8Th4 cuboctahedra that share corners with four equivalent Tb(2)Tb8Th4 cuboctahedra, corners with eight equivalent Th(1)Tb12 cuboctahedra, edges with eight equivalent Tb(2)Tb8Th4 cuboctahedra, edges with sixteen equivalent Tb(1)Tb8Th4 cuboctahedra, faces with four equivalent Tb(2)Tb8Th4 cuboctahedra, faces with six equivalent Th(1)Tb12 cuboctahedra, and faces with eight equivalent Tb(1)Tb8Th4 cuboctahedra.