U2Re2C3 crystallizes in the monoclinic C2/m space group. U(1) is bonded to two equivalent C(2) and three equivalent C(1) atoms to form distorted UC5 square pyramids that share corners with two equivalent U(1)C5 square pyramids, corners with seven equivalent Re(1)C4 trigonal pyramids, edges with five equivalent U(1)C5 square pyramids, and edges with three equivalent Re(1)C4 trigonal pyramids. Re(1) is bonded to one C(2) and three equivalent C(1) atoms to form distorted ReC4 trigonal pyramids that share corners with seven equivalent U(1)C5 square pyramids, corners with three equivalent Re(1)C4 trigonal pyramids, edges with three equivalent U(1)C5 square pyramids, and edges with two equivalent Re(1)C4 trigonal pyramids. There are two inequivalent C sites. In the first C site, C(1) is bonded to three equivalent U(1) and three equivalent Re(1) atoms to form CU3Re3 octahedra that share corners with three equivalent C(2)U4Re2 octahedra, edges with three equivalent C(2)U4Re2 octahedra, and edges with six equivalent C(1)U3Re3 octahedra. The corner-sharing octahedral tilt angles range from 18-27°. In the second C site, C(2) is bonded to four equivalent U(1) and two equivalent Re(1) atoms to form CU4Re2 octahedra that share corners with six equivalent C(1)U3Re3 octahedra, edges with two equivalent C(2)U4Re2 octahedra, and edges with six equivalent C(1)U3Re3 octahedra. The corner-sharing octahedral tilt angles range from 18-27°.
U2Re2C3 crystallizes in the monoclinic C2/m space group. U(1) is bonded to two equivalent C(2) and three equivalent C(1) atoms to form distorted UC5 square pyramids that share corners with two equivalent U(1)C5 square pyramids, corners with seven equivalent Re(1)C4 trigonal pyramids, edges with five equivalent U(1)C5 square pyramids, and edges with three equivalent Re(1)C4 trigonal pyramids. Both U(1)-C(2) bond lengths are 2.47 Å. There is one shorter (2.41 Å) and two longer (2.45 Å) U(1)-C(1) bond lengths. Re(1) is bonded to one C(2) and three equivalent C(1) atoms to form distorted ReC4 trigonal pyramids that share corners with seven equivalent U(1)C5 square pyramids, corners with three equivalent Re(1)C4 trigonal pyramids, edges with three equivalent U(1)C5 square pyramids, and edges with two equivalent Re(1)C4 trigonal pyramids. The Re(1)-C(2) bond length is 2.06 Å. There are two shorter (2.11 Å) and one longer (2.16 Å) Re(1)-C(1) bond length. There are two inequivalent C sites. In the first C site, C(1) is bonded to three equivalent U(1) and three equivalent Re(1) atoms to form CU3Re3 octahedra that share corners with three equivalent C(2)U4Re2 octahedra, edges with three equivalent C(2)U4Re2 octahedra, and edges with six equivalent C(1)U3Re3 octahedra. The corner-sharing octahedral tilt angles range from 18-27°. In the second C site, C(2) is bonded to four equivalent U(1) and two equivalent Re(1) atoms to form CU4Re2 octahedra that share corners with six equivalent C(1)U3Re3 octahedra, edges with two equivalent C(2)U4Re2 octahedra, and edges with six equivalent C(1)U3Re3 octahedra. The corner-sharing octahedral tilt angles range from 18-27°.