Cs6K3AlSb4 crystallizes in the hexagonal P6_3/mmc space group. Cs(1) is bonded in a 3-coordinate geometry to one Sb(1) and four equivalent Sb(2) atoms. K(1) is bonded in a 4-coordinate geometry to two equivalent Sb(1) and two equivalent Sb(2) atoms. Al(1) is bonded in a trigonal planar geometry to three equivalent Sb(2) atoms. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to six equivalent Cs(1) and six equivalent K(1) atoms to form face-sharing SbCs6K6 cuboctahedra. In the second Sb site, Sb(2) is bonded in a 11-coordinate geometry to eight equivalent Cs(1), two equivalent K(1), and one Al(1) atom.
Cs6K3AlSb4 crystallizes in the hexagonal P6_3/mmc space group. Cs(1) is bonded in a 3-coordinate geometry to one Sb(1) and four equivalent Sb(2) atoms. The Cs(1)-Sb(1) bond length is 4.08 Å. There are two shorter (4.09 Å) and two longer (4.29 Å) Cs(1)-Sb(2) bond lengths. K(1) is bonded in a 4-coordinate geometry to two equivalent Sb(1) and two equivalent Sb(2) atoms. Both K(1)-Sb(1) bond lengths are 3.73 Å. Both K(1)-Sb(2) bond lengths are 3.64 Å. Al(1) is bonded in a trigonal planar geometry to three equivalent Sb(2) atoms. All Al(1)-Sb(2) bond lengths are 2.69 Å. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to six equivalent Cs(1) and six equivalent K(1) atoms to form face-sharing SbCs6K6 cuboctahedra. In the second Sb site, Sb(2) is bonded in a 11-coordinate geometry to eight equivalent Cs(1), two equivalent K(1), and one Al(1) atom.