CTh5 crystallizes in the trigonal R-3m space group. There are three inequivalent Th sites. In the first Th site, Th(1) is bonded to three equivalent Th(2), three equivalent Th(3), and six equivalent Th(1) atoms to form ThTh12 cuboctahedra that share corners with nine equivalent Th(1)Th12 cuboctahedra, corners with six equivalent C(1)Th6 octahedra, edges with six equivalent Th(2)Th12 cuboctahedra, edges with nine equivalent Th(1)Th12 cuboctahedra, faces with six equivalent Th(1)Th12 cuboctahedra, faces with six equivalent Th(2)Th12 cuboctahedra, and  a faceface with one C(1)Th6 octahedra. The corner-sharing octahedral tilt angles are 45°. In the second Th site, Th(2) is bonded to six equivalent Th(1) and six equivalent Th(2) atoms to form a mixture of edge, corner, and face-sharing ThTh12 cuboctahedra. In the third Th site, Th(3) is bonded in a distorted T-shaped geometry to three equivalent Th(1) and three equivalent C(1) atoms. C(1) is bonded to six equivalent Th(3) atoms to form CTh6 octahedra that share corners with twelve equivalent Th(1)Th12 cuboctahedra, edges with six equivalent C(1)Th6 octahedra, and faces with two equivalent Th(1)Th12 cuboctahedra.
CTh5 crystallizes in the trigonal R-3m space group. There are three inequivalent Th sites. In the first Th site, Th(1) is bonded to three equivalent Th(2), three equivalent Th(3), and six equivalent Th(1) atoms to form ThTh12 cuboctahedra that share corners with nine equivalent Th(1)Th12 cuboctahedra, corners with six equivalent C(1)Th6 octahedra, edges with six equivalent Th(2)Th12 cuboctahedra, edges with nine equivalent Th(1)Th12 cuboctahedra, faces with six equivalent Th(1)Th12 cuboctahedra, faces with six equivalent Th(2)Th12 cuboctahedra, and  a faceface with one C(1)Th6 octahedra. The corner-sharing octahedral tilt angles are 45°. All Th(1)-Th(2) bond lengths are 3.57 Å. All Th(1)-Th(3) bond lengths are 3.73 Å. All Th(1)-Th(1) bond lengths are 3.61 Å. In the second Th site, Th(2) is bonded to six equivalent Th(1) and six equivalent Th(2) atoms to form a mixture of edge, corner, and face-sharing ThTh12 cuboctahedra. All Th(2)-Th(2) bond lengths are 3.61 Å. In the third Th site, Th(3) is bonded in a distorted T-shaped geometry to three equivalent Th(1) and three equivalent C(1) atoms. All Th(3)-C(1) bond lengths are 2.57 Å. C(1) is bonded to six equivalent Th(3) atoms to form CTh6 octahedra that share corners with twelve equivalent Th(1)Th12 cuboctahedra, edges with six equivalent C(1)Th6 octahedra, and faces with two equivalent Th(1)Th12 cuboctahedra.