Lu5Sb3 crystallizes in the orthorhombic Pnma space group. There are four inequivalent Lu sites. In the first Lu site, Lu(1) is bonded in a 5-coordinate geometry to two equivalent Sb(2) and three equivalent Sb(1) atoms. In the second Lu site, Lu(2) is bonded to one Sb(2) and four equivalent Sb(1) atoms to form distorted edge-sharing LuSb5 square pyramids. In the third Lu site, Lu(3) is bonded in a 6-coordinate geometry to two equivalent Sb(2) and four equivalent Sb(1) atoms. In the fourth Lu site, Lu(4) is bonded in a 5-coordinate geometry to one Sb(2) and four equivalent Sb(1) atoms. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 9-coordinate geometry to two equivalent Lu(2), two equivalent Lu(3), two equivalent Lu(4), and three equivalent Lu(1) atoms. In the second Sb site, Sb(2) is bonded in a 8-coordinate geometry to one Lu(2), one Lu(4), two equivalent Lu(3), and four equivalent Lu(1) atoms.
Lu5Sb3 crystallizes in the orthorhombic Pnma space group. There are four inequivalent Lu sites. In the first Lu site, Lu(1) is bonded in a 5-coordinate geometry to two equivalent Sb(2) and three equivalent Sb(1) atoms. There is one shorter (2.97 Å) and one longer (3.05 Å) Lu(1)-Sb(2) bond length. There are a spread of Lu(1)-Sb(1) bond distances ranging from 3.26-3.36 Å. In the second Lu site, Lu(2) is bonded to one Sb(2) and four equivalent Sb(1) atoms to form distorted edge-sharing LuSb5 square pyramids. The Lu(2)-Sb(2) bond length is 3.04 Å. There are two shorter (3.06 Å) and two longer (3.10 Å) Lu(2)-Sb(1) bond lengths. In the third Lu site, Lu(3) is bonded in a 6-coordinate geometry to two equivalent Sb(2) and four equivalent Sb(1) atoms. There is one shorter (3.00 Å) and one longer (3.31 Å) Lu(3)-Sb(2) bond length. There are two shorter (3.07 Å) and two longer (3.29 Å) Lu(3)-Sb(1) bond lengths. In the fourth Lu site, Lu(4) is bonded in a 5-coordinate geometry to one Sb(2) and four equivalent Sb(1) atoms. The Lu(4)-Sb(2) bond length is 2.98 Å. There are two shorter (3.07 Å) and two longer (3.24 Å) Lu(4)-Sb(1) bond lengths. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 9-coordinate geometry to two equivalent Lu(2), two equivalent Lu(3), two equivalent Lu(4), and three equivalent Lu(1) atoms. In the second Sb site, Sb(2) is bonded in a 8-coordinate geometry to one Lu(2), one Lu(4), two equivalent Lu(3), and four equivalent Lu(1) atoms.