U3TaSb5 crystallizes in the monoclinic C2/m space group. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 9-coordinate geometry to two equivalent Sb(2), two equivalent Sb(3), two equivalent Sb(4), and three equivalent Sb(1) atoms. In the second U site, U(2) is bonded in a 9-coordinate geometry to one Sb(1), two equivalent Sb(3), two equivalent Sb(4), and four equivalent Sb(2) atoms. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to two equivalent Sb(1) and four equivalent Sb(2) atoms to form face-sharing TaSb6 octahedra. In the second Ta site, Ta(2) is bonded to two equivalent Sb(1) and four equivalent Sb(2) atoms to form face-sharing TaSb6 octahedra. There are four inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to two equivalent U(2), three equivalent U(1), one Ta(1), and one Ta(2) atom to form a mixture of distorted edge, face, and corner-sharing SbU5Ta2 pentagonal bipyramids. In the second Sb site, Sb(2) is bonded to one U(1), four equivalent U(2), one Ta(1), and one Ta(2) atom to form a mixture of distorted edge, face, and corner-sharing SbU5Ta2 pentagonal bipyramids. In the third Sb site, Sb(3) is bonded in a 8-coordinate geometry to two equivalent U(1), four equivalent U(2), and two equivalent Sb(4) atoms. In the fourth Sb site, Sb(4) is bonded in a 8-coordinate geometry to two equivalent U(1), four equivalent U(2), and two equivalent Sb(3) atoms.
U3TaSb5 crystallizes in the monoclinic C2/m space group. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 9-coordinate geometry to two equivalent Sb(2), two equivalent Sb(3), two equivalent Sb(4), and three equivalent Sb(1) atoms. Both U(1)-Sb(2) bond lengths are 3.17 Å. Both U(1)-Sb(3) bond lengths are 3.27 Å. Both U(1)-Sb(4) bond lengths are 3.27 Å. There are a spread of U(1)-Sb(1) bond distances ranging from 3.26-3.34 Å. In the second U site, U(2) is bonded in a 9-coordinate geometry to one Sb(1), two equivalent Sb(3), two equivalent Sb(4), and four equivalent Sb(2) atoms. The U(2)-Sb(1) bond length is 3.17 Å. There is one shorter (3.26 Å) and one longer (3.27 Å) U(2)-Sb(3) bond length. There is one shorter (3.26 Å) and one longer (3.28 Å) U(2)-Sb(4) bond length. There are a spread of U(2)-Sb(2) bond distances ranging from 3.17-3.33 Å. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to two equivalent Sb(1) and four equivalent Sb(2) atoms to form face-sharing TaSb6 octahedra. Both Ta(1)-Sb(1) bond lengths are 2.88 Å. All Ta(1)-Sb(2) bond lengths are 2.88 Å. In the second Ta site, Ta(2) is bonded to two equivalent Sb(1) and four equivalent Sb(2) atoms to form face-sharing TaSb6 octahedra. Both Ta(2)-Sb(1) bond lengths are 2.88 Å. All Ta(2)-Sb(2) bond lengths are 2.88 Å. There are four inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to two equivalent U(2), three equivalent U(1), one Ta(1), and one Ta(2) atom to form a mixture of distorted edge, face, and corner-sharing SbU5Ta2 pentagonal bipyramids. In the second Sb site, Sb(2) is bonded to one U(1), four equivalent U(2), one Ta(1), and one Ta(2) atom to form a mixture of distorted edge, face, and corner-sharing SbU5Ta2 pentagonal bipyramids. In the third Sb site, Sb(3) is bonded in a 8-coordinate geometry to two equivalent U(1), four equivalent U(2), and two equivalent Sb(4) atoms. Both Sb(3)-Sb(4) bond lengths are 3.09 Å. In the fourth Sb site, Sb(4) is bonded in a 8-coordinate geometry to two equivalent U(1), four equivalent U(2), and two equivalent Sb(3) atoms.