Lu5Tl3 crystallizes in the orthorhombic Cmcm space group. There are three inequivalent Lu sites. In the first Lu site, Lu(1) is bonded in a 6-coordinate geometry to two equivalent Tl(1) and four equivalent Tl(2) atoms. In the second Lu site, Lu(2) is bonded in a 5-coordinate geometry to two equivalent Tl(2) and three equivalent Tl(1) atoms. In the third Lu site, Lu(3) is bonded in a 5-coordinate geometry to one Tl(1) and four equivalent Tl(2) atoms. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a 9-coordinate geometry to two equivalent Lu(3), three equivalent Lu(2), and four equivalent Lu(1) atoms. In the second Tl site, Tl(2) is bonded in a 9-coordinate geometry to one Lu(2), four equivalent Lu(1), and four equivalent Lu(3) atoms.
Lu5Tl3 crystallizes in the orthorhombic Cmcm space group. There are three inequivalent Lu sites. In the first Lu site, Lu(1) is bonded in a 6-coordinate geometry to two equivalent Tl(1) and four equivalent Tl(2) atoms. Both Lu(1)-Tl(1) bond lengths are 3.18 Å. All Lu(1)-Tl(2) bond lengths are 3.17 Å. In the second Lu site, Lu(2) is bonded in a 5-coordinate geometry to two equivalent Tl(2) and three equivalent Tl(1) atoms. Both Lu(2)-Tl(2) bond lengths are 3.03 Å. There is one shorter (3.17 Å) and two longer (3.51 Å) Lu(2)-Tl(1) bond lengths. In the third Lu site, Lu(3) is bonded in a 5-coordinate geometry to one Tl(1) and four equivalent Tl(2) atoms. The Lu(3)-Tl(1) bond length is 3.03 Å. There are a spread of Lu(3)-Tl(2) bond distances ranging from 3.02-3.51 Å. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a 9-coordinate geometry to two equivalent Lu(3), three equivalent Lu(2), and four equivalent Lu(1) atoms. In the second Tl site, Tl(2) is bonded in a 9-coordinate geometry to one Lu(2), four equivalent Lu(1), and four equivalent Lu(3) atoms.