K3Ac is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. K(1) is bonded to eight equivalent K(1) and four equivalent Ac(1) atoms to form KK8Ac4 cuboctahedra that share corners with four equivalent Ac(1)K12 cuboctahedra, corners with fourteen equivalent K(1)K8Ac4 cuboctahedra, edges with six equivalent Ac(1)K12 cuboctahedra, edges with twelve equivalent K(1)K8Ac4 cuboctahedra, faces with four equivalent Ac(1)K12 cuboctahedra, and faces with sixteen equivalent K(1)K8Ac4 cuboctahedra. Ac(1) is bonded to twelve equivalent K(1) atoms to form AcK12 cuboctahedra that share corners with six equivalent Ac(1)K12 cuboctahedra, corners with twelve equivalent K(1)K8Ac4 cuboctahedra, edges with eighteen equivalent K(1)K8Ac4 cuboctahedra, faces with eight equivalent Ac(1)K12 cuboctahedra, and faces with twelve equivalent K(1)K8Ac4 cuboctahedra.
K3Ac is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. K(1) is bonded to eight equivalent K(1) and four equivalent Ac(1) atoms to form KK8Ac4 cuboctahedra that share corners with four equivalent Ac(1)K12 cuboctahedra, corners with fourteen equivalent K(1)K8Ac4 cuboctahedra, edges with six equivalent Ac(1)K12 cuboctahedra, edges with twelve equivalent K(1)K8Ac4 cuboctahedra, faces with four equivalent Ac(1)K12 cuboctahedra, and faces with sixteen equivalent K(1)K8Ac4 cuboctahedra. There are two shorter (4.39 Å) and six longer (4.48 Å) K(1)-K(1) bond lengths. There are two shorter (4.44 Å) and two longer (4.46 Å) K(1)-Ac(1) bond lengths. Ac(1) is bonded to twelve equivalent K(1) atoms to form AcK12 cuboctahedra that share corners with six equivalent Ac(1)K12 cuboctahedra, corners with twelve equivalent K(1)K8Ac4 cuboctahedra, edges with eighteen equivalent K(1)K8Ac4 cuboctahedra, faces with eight equivalent Ac(1)K12 cuboctahedra, and faces with twelve equivalent K(1)K8Ac4 cuboctahedra.