K3Ba crystallizes in the tetragonal I4/mmm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to four equivalent K(1), four equivalent K(2), and four equivalent Ba(1) atoms to form distorted KK8Ba4 cuboctahedra that share corners with twelve equivalent K(1)K8Ba4 cuboctahedra, edges with eight equivalent K(1)K8Ba4 cuboctahedra, edges with eight equivalent Ba(1)K12 cuboctahedra, faces with four equivalent Ba(1)K12 cuboctahedra, and faces with ten equivalent K(1)K8Ba4 cuboctahedra. In the second K site, K(2) is bonded in a square co-planar geometry to eight equivalent K(1) and four equivalent Ba(1) atoms. Ba(1) is bonded to four equivalent K(2) and eight equivalent K(1) atoms to form BaK12 cuboctahedra that share corners with four equivalent Ba(1)K12 cuboctahedra, edges with eight equivalent Ba(1)K12 cuboctahedra, edges with sixteen equivalent K(1)K8Ba4 cuboctahedra, faces with four equivalent Ba(1)K12 cuboctahedra, and faces with eight equivalent K(1)K8Ba4 cuboctahedra.
K3Ba crystallizes in the tetragonal I4/mmm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to four equivalent K(1), four equivalent K(2), and four equivalent Ba(1) atoms to form distorted KK8Ba4 cuboctahedra that share corners with twelve equivalent K(1)K8Ba4 cuboctahedra, edges with eight equivalent K(1)K8Ba4 cuboctahedra, edges with eight equivalent Ba(1)K12 cuboctahedra, faces with four equivalent Ba(1)K12 cuboctahedra, and faces with ten equivalent K(1)K8Ba4 cuboctahedra. All K(1)-K(1) bond lengths are 4.44 Å. All K(1)-K(2) bond lengths are 4.77 Å. All K(1)-Ba(1) bond lengths are 4.77 Å. In the second K site, K(2) is bonded in a square co-planar geometry to eight equivalent K(1) and four equivalent Ba(1) atoms. All K(2)-Ba(1) bond lengths are 4.44 Å. Ba(1) is bonded to four equivalent K(2) and eight equivalent K(1) atoms to form BaK12 cuboctahedra that share corners with four equivalent Ba(1)K12 cuboctahedra, edges with eight equivalent Ba(1)K12 cuboctahedra, edges with sixteen equivalent K(1)K8Ba4 cuboctahedra, faces with four equivalent Ba(1)K12 cuboctahedra, and faces with eight equivalent K(1)K8Ba4 cuboctahedra.