AcY3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. Ac(1) is bonded to four equivalent Y(2) and eight equivalent Y(1) atoms to form AcY12 cuboctahedra that share corners with four equivalent Ac(1)Y12 cuboctahedra, corners with eight equivalent Y(2)Ac4Y8 cuboctahedra, edges with eight equivalent Ac(1)Y12 cuboctahedra, edges with sixteen equivalent Y(1)Ac4Y8 cuboctahedra, faces with four equivalent Ac(1)Y12 cuboctahedra, faces with six equivalent Y(2)Ac4Y8 cuboctahedra, and faces with eight equivalent Y(1)Ac4Y8 cuboctahedra. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to four equivalent Ac(1), four equivalent Y(1), and four equivalent Y(2) atoms to form YAc4Y8 cuboctahedra that share corners with twelve equivalent Y(1)Ac4Y8 cuboctahedra, edges with eight equivalent Ac(1)Y12 cuboctahedra, edges with eight equivalent Y(1)Ac4Y8 cuboctahedra, edges with eight equivalent Y(2)Ac4Y8 cuboctahedra, faces with four equivalent Ac(1)Y12 cuboctahedra, faces with four equivalent Y(2)Ac4Y8 cuboctahedra, and faces with ten equivalent Y(1)Ac4Y8 cuboctahedra. In the second Y site, Y(2) is bonded to four equivalent Ac(1) and eight equivalent Y(1) atoms to form YAc4Y8 cuboctahedra that share corners with four equivalent Y(2)Ac4Y8 cuboctahedra, corners with eight equivalent Ac(1)Y12 cuboctahedra, edges with eight equivalent Y(2)Ac4Y8 cuboctahedra, edges with sixteen equivalent Y(1)Ac4Y8 cuboctahedra, faces with four equivalent Y(2)Ac4Y8 cuboctahedra, faces with six equivalent Ac(1)Y12 cuboctahedra, and faces with eight equivalent Y(1)Ac4Y8 cuboctahedra.
AcY3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. Ac(1) is bonded to four equivalent Y(2) and eight equivalent Y(1) atoms to form AcY12 cuboctahedra that share corners with four equivalent Ac(1)Y12 cuboctahedra, corners with eight equivalent Y(2)Ac4Y8 cuboctahedra, edges with eight equivalent Ac(1)Y12 cuboctahedra, edges with sixteen equivalent Y(1)Ac4Y8 cuboctahedra, faces with four equivalent Ac(1)Y12 cuboctahedra, faces with six equivalent Y(2)Ac4Y8 cuboctahedra, and faces with eight equivalent Y(1)Ac4Y8 cuboctahedra. All Ac(1)-Y(2) bond lengths are 3.75 Å. All Ac(1)-Y(1) bond lengths are 3.69 Å. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to four equivalent Ac(1), four equivalent Y(1), and four equivalent Y(2) atoms to form YAc4Y8 cuboctahedra that share corners with twelve equivalent Y(1)Ac4Y8 cuboctahedra, edges with eight equivalent Ac(1)Y12 cuboctahedra, edges with eight equivalent Y(1)Ac4Y8 cuboctahedra, edges with eight equivalent Y(2)Ac4Y8 cuboctahedra, faces with four equivalent Ac(1)Y12 cuboctahedra, faces with four equivalent Y(2)Ac4Y8 cuboctahedra, and faces with ten equivalent Y(1)Ac4Y8 cuboctahedra. All Y(1)-Y(1) bond lengths are 3.75 Å. All Y(1)-Y(2) bond lengths are 3.69 Å. In the second Y site, Y(2) is bonded to four equivalent Ac(1) and eight equivalent Y(1) atoms to form YAc4Y8 cuboctahedra that share corners with four equivalent Y(2)Ac4Y8 cuboctahedra, corners with eight equivalent Ac(1)Y12 cuboctahedra, edges with eight equivalent Y(2)Ac4Y8 cuboctahedra, edges with sixteen equivalent Y(1)Ac4Y8 cuboctahedra, faces with four equivalent Y(2)Ac4Y8 cuboctahedra, faces with six equivalent Ac(1)Y12 cuboctahedra, and faces with eight equivalent Y(1)Ac4Y8 cuboctahedra.