ThTb crystallizes in the trigonal R-3m space group. Th(1) is bonded to six equivalent Th(1) and six equivalent Tb(1) atoms to form ThTb6Th6 cuboctahedra that share corners with twelve equivalent Th(1)Tb6Th6 cuboctahedra, edges with twelve equivalent Th(1)Tb6Th6 cuboctahedra, edges with twelve equivalent Tb(1)Tb6Th6 cuboctahedra, faces with six equivalent Th(1)Tb6Th6 cuboctahedra, and faces with twelve equivalent Tb(1)Tb6Th6 cuboctahedra. Tb(1) is bonded to six equivalent Th(1) and six equivalent Tb(1) atoms to form TbTb6Th6 cuboctahedra that share corners with twelve equivalent Tb(1)Tb6Th6 cuboctahedra, edges with twelve equivalent Th(1)Tb6Th6 cuboctahedra, edges with twelve equivalent Tb(1)Tb6Th6 cuboctahedra, faces with six equivalent Tb(1)Tb6Th6 cuboctahedra, and faces with twelve equivalent Th(1)Tb6Th6 cuboctahedra.
ThTb crystallizes in the trigonal R-3m space group. Th(1) is bonded to six equivalent Th(1) and six equivalent Tb(1) atoms to form ThTb6Th6 cuboctahedra that share corners with twelve equivalent Th(1)Tb6Th6 cuboctahedra, edges with twelve equivalent Th(1)Tb6Th6 cuboctahedra, edges with twelve equivalent Tb(1)Tb6Th6 cuboctahedra, faces with six equivalent Th(1)Tb6Th6 cuboctahedra, and faces with twelve equivalent Tb(1)Tb6Th6 cuboctahedra. All Th(1)-Th(1) bond lengths are 3.58 Å. All Th(1)-Tb(1) bond lengths are 3.54 Å. Tb(1) is bonded to six equivalent Th(1) and six equivalent Tb(1) atoms to form TbTb6Th6 cuboctahedra that share corners with twelve equivalent Tb(1)Tb6Th6 cuboctahedra, edges with twelve equivalent Th(1)Tb6Th6 cuboctahedra, edges with twelve equivalent Tb(1)Tb6Th6 cuboctahedra, faces with six equivalent Tb(1)Tb6Th6 cuboctahedra, and faces with twelve equivalent Th(1)Tb6Th6 cuboctahedra. All Tb(1)-Tb(1) bond lengths are 3.58 Å.