K5Sb4 crystallizes in the monoclinic C2/m space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to two equivalent Sb(1) and five equivalent Sb(2) atoms. In the second K site, K(2) is bonded in a 6-coordinate geometry to two equivalent Sb(2) and four equivalent Sb(1) atoms. In the third K site, K(3) is bonded in a distorted square co-planar geometry to 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 K(1), two equivalent K(3), four equivalent K(2), and one Sb(2) atom. In the second Sb site, Sb(2) is bonded in a 9-coordinate geometry to two equivalent K(2), five equivalent K(1), one Sb(1), and one Sb(2) atom.
K5Sb4 crystallizes in the monoclinic C2/m space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to two equivalent Sb(1) and five equivalent Sb(2) atoms. Both K(1)-Sb(1) bond lengths are 3.67 Å. There are a spread of K(1)-Sb(2) bond distances ranging from 3.66-3.75 Å. In the second K site, K(2) is bonded in a 6-coordinate geometry to two equivalent Sb(2) and four equivalent Sb(1) atoms. Both K(2)-Sb(2) bond lengths are 3.72 Å. There are a spread of K(2)-Sb(1) bond distances ranging from 3.69-3.81 Å. In the third K site, K(3) is bonded in a distorted square co-planar geometry to four equivalent Sb(1) atoms. All K(3)-Sb(1) bond lengths are 3.56 Å. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 9-coordinate geometry to two equivalent K(1), two equivalent K(3), four equivalent K(2), and one Sb(2) atom. The Sb(1)-Sb(2) bond length is 2.81 Å. In the second Sb site, Sb(2) is bonded in a 9-coordinate geometry to two equivalent K(2), five equivalent K(1), one Sb(1), and one Sb(2) atom. The Sb(2)-Sb(2) bond length is 2.85 Å.