U2Co3Al9 crystallizes in the orthorhombic Cmcm space group. U(1) is bonded in a 11-coordinate geometry to one Al(4), two equivalent Al(1), two equivalent Al(3), and six equivalent Al(2) atoms. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a 8-coordinate geometry to two equivalent Al(1), two equivalent Al(3), and four equivalent Al(2) atoms. In the second Co site, Co(2) is bonded in a 8-coordinate geometry to two equivalent Al(1), two equivalent Al(4), and four equivalent Al(2) atoms. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded in a 3-coordinate geometry to two equivalent U(1), one Co(2), and two equivalent Co(1) atoms. In the second Al site, Al(2) is bonded in a 3-coordinate geometry to three equivalent U(1), one Co(2), and two equivalent Co(1) atoms. In the third Al site, Al(3) is bonded in a 2-coordinate geometry to two equivalent U(1) and two equivalent Co(1) atoms. In the fourth Al site, Al(4) is bonded in a 2-coordinate geometry to two equivalent U(1) and two equivalent Co(2) atoms.
U2Co3Al9 crystallizes in the orthorhombic Cmcm space group. U(1) is bonded in a 11-coordinate geometry to one Al(4), two equivalent Al(1), two equivalent Al(3), and six equivalent Al(2) atoms. The U(1)-Al(4) bond length is 3.01 Å. Both U(1)-Al(1) bond lengths are 3.05 Å. There is one shorter (2.98 Å) and one longer (3.10 Å) U(1)-Al(3) bond length. There are a spread of U(1)-Al(2) bond distances ranging from 2.97-3.01 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a 8-coordinate geometry to two equivalent Al(1), two equivalent Al(3), and four equivalent Al(2) atoms. Both Co(1)-Al(1) bond lengths are 2.59 Å. Both Co(1)-Al(3) bond lengths are 2.48 Å. There are two shorter (2.48 Å) and two longer (2.59 Å) Co(1)-Al(2) bond lengths. In the second Co site, Co(2) is bonded in a 8-coordinate geometry to two equivalent Al(1), two equivalent Al(4), and four equivalent Al(2) atoms. Both Co(2)-Al(1) bond lengths are 2.54 Å. Both Co(2)-Al(4) bond lengths are 2.49 Å. All Co(2)-Al(2) bond lengths are 2.59 Å. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded in a 3-coordinate geometry to two equivalent U(1), one Co(2), and two equivalent Co(1) atoms. In the second Al site, Al(2) is bonded in a 3-coordinate geometry to three equivalent U(1), one Co(2), and two equivalent Co(1) atoms. In the third Al site, Al(3) is bonded in a 2-coordinate geometry to two equivalent U(1) and two equivalent Co(1) atoms. In the fourth Al site, Al(4) is bonded in a 2-coordinate geometry to two equivalent U(1) and two equivalent Co(2) atoms.