U3NbSb5 crystallizes in the trigonal P-31m space group. U(1) is bonded in a 9-coordinate geometry to two equivalent Sb(1), two equivalent Sb(3), and five equivalent Sb(2) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to six equivalent Sb(2) atoms to form face-sharing NbSb6 octahedra. In the second Nb site, Nb(2) is bonded to six equivalent Sb(2) atoms to form face-sharing NbSb6 octahedra. There are three inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 8-coordinate geometry to six equivalent U(1) and two equivalent Sb(3) atoms. In the second Sb site, Sb(2) is bonded to five equivalent U(1), one Nb(1), and one Nb(2) atom to form a mixture of distorted corner, face, and edge-sharing SbU5Nb2 pentagonal bipyramids. In the third Sb site, Sb(3) is bonded in a 8-coordinate geometry to six equivalent U(1) and two equivalent Sb(1) atoms.
U3NbSb5 crystallizes in the trigonal P-31m space group. U(1) is bonded in a 9-coordinate geometry to two equivalent Sb(1), two equivalent Sb(3), and five equivalent Sb(2) atoms. Both U(1)-Sb(1) bond lengths are 3.28 Å. Both U(1)-Sb(3) bond lengths are 3.26 Å. There are a spread of U(1)-Sb(2) bond distances ranging from 3.17-3.32 Å. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to six equivalent Sb(2) atoms to form face-sharing NbSb6 octahedra. All Nb(1)-Sb(2) bond lengths are 2.90 Å. In the second Nb site, Nb(2) is bonded to six equivalent Sb(2) atoms to form face-sharing NbSb6 octahedra. All Nb(2)-Sb(2) bond lengths are 2.89 Å. There are three inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 8-coordinate geometry to six equivalent U(1) and two equivalent Sb(3) atoms. Both Sb(1)-Sb(3) bond lengths are 3.10 Å. In the second Sb site, Sb(2) is bonded to five equivalent U(1), one Nb(1), and one Nb(2) atom to form a mixture of distorted corner, face, and edge-sharing SbU5Nb2 pentagonal bipyramids. In the third Sb site, Sb(3) is bonded in a 8-coordinate geometry to six equivalent U(1) and two equivalent Sb(1) atoms.