U2Re2C3 crystallizes in the monoclinic C2/m space group. U(1) is bonded in a distorted pentagonal planar geometry to two equivalent C(1) and three equivalent C(2) atoms. Re(1) is bonded to one C(1) and three equivalent C(2) atoms to form a mixture of distorted edge and corner-sharing ReC4 trigonal pyramids. There are two inequivalent C sites. In the first C site, C(1) is bonded to four equivalent U(1) and two equivalent Re(1) atoms to form CU4Re2 octahedra that share corners with twelve equivalent C(2)U3Re3 octahedra, edges with two equivalent C(1)U4Re2 octahedra, and faces with two equivalent C(2)U3Re3 octahedra. The corner-sharing octahedral tilt angles range from 39-60°. In the second C site, C(2) is bonded to three equivalent U(1) and three equivalent Re(1) atoms to form CU3Re3 octahedra that share corners with six equivalent C(1)U4Re2 octahedra, edges with six equivalent C(2)U3Re3 octahedra, and  a faceface with one C(1)U4Re2 octahedra. The corner-sharing octahedral tilt angles range from 39-60°.
U2Re2C3 crystallizes in the monoclinic C2/m space group. U(1) is bonded in a distorted pentagonal planar geometry to two equivalent C(1) and three equivalent C(2) atoms. Both U(1)-C(1) bond lengths are 2.43 Å. There are two shorter (2.42 Å) and one longer (2.47 Å) U(1)-C(2) bond length. Re(1) is bonded to one C(1) and three equivalent C(2) atoms to form a mixture of distorted edge and corner-sharing ReC4 trigonal pyramids. The Re(1)-C(1) bond length is 2.10 Å. There are two shorter (2.09 Å) and one longer (2.18 Å) Re(1)-C(2) bond length. There are two inequivalent C sites. In the first C site, C(1) is bonded to four equivalent U(1) and two equivalent Re(1) atoms to form CU4Re2 octahedra that share corners with twelve equivalent C(2)U3Re3 octahedra, edges with two equivalent C(1)U4Re2 octahedra, and faces with two equivalent C(2)U3Re3 octahedra. The corner-sharing octahedral tilt angles range from 39-60°. In the second C site, C(2) is bonded to three equivalent U(1) and three equivalent Re(1) atoms to form CU3Re3 octahedra that share corners with six equivalent C(1)U4Re2 octahedra, edges with six equivalent C(2)U3Re3 octahedra, and  a faceface with one C(1)U4Re2 octahedra. The corner-sharing octahedral tilt angles range from 39-60°.