Th2Al2C3 crystallizes in the orthorhombic Pnnm space group. Th(1) is bonded to two equivalent C(2) and four equivalent C(1) atoms to form a mixture of distorted edge and corner-sharing ThC6 octahedra. The corner-sharing octahedral tilt angles range from 0-19°. Al(1) is bonded in a trigonal non-coplanar geometry to one C(2) and two equivalent C(1) atoms. There are two inequivalent C sites. In the first C site, C(1) is bonded to four equivalent Th(1) and two equivalent Al(1) atoms to form a mixture of distorted edge and corner-sharing CTh4Al2 octahedra. The corner-sharing octahedral tilt angles range from 19-62°. In the second C site, C(2) is bonded to four equivalent Th(1) and two equivalent Al(1) atoms to form a mixture of edge and corner-sharing CTh4Al2 octahedra. The corner-sharing octahedral tilt angles range from 22-62°.
Th2Al2C3 crystallizes in the orthorhombic Pnnm space group. Th(1) is bonded to two equivalent C(2) and four equivalent C(1) atoms to form a mixture of distorted edge and corner-sharing ThC6 octahedra. The corner-sharing octahedral tilt angles range from 0-19°. Both Th(1)-C(2) bond lengths are 2.64 Å. There are a spread of Th(1)-C(1) bond distances ranging from 2.58-2.79 Å. Al(1) is bonded in a trigonal non-coplanar geometry to one C(2) and two equivalent C(1) atoms. The Al(1)-C(2) bond length is 1.97 Å. Both Al(1)-C(1) bond lengths are 2.12 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded to four equivalent Th(1) and two equivalent Al(1) atoms to form a mixture of distorted edge and corner-sharing CTh4Al2 octahedra. The corner-sharing octahedral tilt angles range from 19-62°. In the second C site, C(2) is bonded to four equivalent Th(1) and two equivalent Al(1) atoms to form a mixture of edge and corner-sharing CTh4Al2 octahedra. The corner-sharing octahedral tilt angles range from 22-62°.