K5Bi4 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 Bi(2) and five equivalent Bi(1) atoms. In the second K site, K(2) is bonded in a 6-coordinate geometry to two equivalent Bi(1) and four equivalent Bi(2) atoms. In the third K site, K(3) is bonded in a distorted square co-planar geometry to four equivalent Bi(2) atoms. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 9-coordinate geometry to two equivalent K(2), five equivalent K(1), one Bi(1), and one Bi(2) atom. In the second Bi site, Bi(2) is bonded in a 9-coordinate geometry to two equivalent K(1), two equivalent K(3), four equivalent K(2), and one Bi(1) atom.
K5Bi4 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 Bi(2) and five equivalent Bi(1) atoms. Both K(1)-Bi(2) bond lengths are 3.75 Å. There are a spread of K(1)-Bi(1) bond distances ranging from 3.72-3.83 Å. In the second K site, K(2) is bonded in a 6-coordinate geometry to two equivalent Bi(1) and four equivalent Bi(2) atoms. Both K(2)-Bi(1) bond lengths are 3.79 Å. There are a spread of K(2)-Bi(2) bond distances ranging from 3.76-3.89 Å. In the third K site, K(3) is bonded in a distorted square co-planar geometry to four equivalent Bi(2) atoms. All K(3)-Bi(2) bond lengths are 3.59 Å. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 9-coordinate geometry to two equivalent K(2), five equivalent K(1), one Bi(1), and one Bi(2) atom. The Bi(1)-Bi(1) bond length is 3.01 Å. The Bi(1)-Bi(2) bond length is 2.98 Å. In the second Bi site, Bi(2) is bonded in a 9-coordinate geometry to two equivalent K(1), two equivalent K(3), four equivalent K(2), and one Bi(1) atom.