KEu3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. K(1) is bonded to four equivalent Eu(2) and eight equivalent Eu(1) atoms to form KEu12 cuboctahedra that share corners with four equivalent K(1)Eu12 cuboctahedra, corners with eight equivalent Eu(2)K4Eu8 cuboctahedra, edges with eight equivalent K(1)Eu12 cuboctahedra, edges with sixteen equivalent Eu(1)K4Eu8 cuboctahedra, faces with four equivalent K(1)Eu12 cuboctahedra, faces with six equivalent Eu(2)K4Eu8 cuboctahedra, and faces with eight equivalent Eu(1)K4Eu8 cuboctahedra. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded to four equivalent K(1), four equivalent Eu(1), and four equivalent Eu(2) atoms to form EuK4Eu8 cuboctahedra that share corners with twelve equivalent Eu(1)K4Eu8 cuboctahedra, edges with eight equivalent K(1)Eu12 cuboctahedra, edges with eight equivalent Eu(1)K4Eu8 cuboctahedra, edges with eight equivalent Eu(2)K4Eu8 cuboctahedra, faces with four equivalent K(1)Eu12 cuboctahedra, faces with four equivalent Eu(2)K4Eu8 cuboctahedra, and faces with ten equivalent Eu(1)K4Eu8 cuboctahedra. In the second Eu site, Eu(2) is bonded to four equivalent K(1) and eight equivalent Eu(1) atoms to form distorted EuK4Eu8 cuboctahedra that share corners with four equivalent Eu(2)K4Eu8 cuboctahedra, corners with eight equivalent K(1)Eu12 cuboctahedra, edges with eight equivalent Eu(2)K4Eu8 cuboctahedra, edges with sixteen equivalent Eu(1)K4Eu8 cuboctahedra, faces with four equivalent Eu(2)K4Eu8 cuboctahedra, faces with six equivalent K(1)Eu12 cuboctahedra, and faces with eight equivalent Eu(1)K4Eu8 cuboctahedra.
KEu3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. K(1) is bonded to four equivalent Eu(2) and eight equivalent Eu(1) atoms to form KEu12 cuboctahedra that share corners with four equivalent K(1)Eu12 cuboctahedra, corners with eight equivalent Eu(2)K4Eu8 cuboctahedra, edges with eight equivalent K(1)Eu12 cuboctahedra, edges with sixteen equivalent Eu(1)K4Eu8 cuboctahedra, faces with four equivalent K(1)Eu12 cuboctahedra, faces with six equivalent Eu(2)K4Eu8 cuboctahedra, and faces with eight equivalent Eu(1)K4Eu8 cuboctahedra. All K(1)-Eu(2) bond lengths are 4.13 Å. All K(1)-Eu(1) bond lengths are 4.20 Å. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded to four equivalent K(1), four equivalent Eu(1), and four equivalent Eu(2) atoms to form EuK4Eu8 cuboctahedra that share corners with twelve equivalent Eu(1)K4Eu8 cuboctahedra, edges with eight equivalent K(1)Eu12 cuboctahedra, edges with eight equivalent Eu(1)K4Eu8 cuboctahedra, edges with eight equivalent Eu(2)K4Eu8 cuboctahedra, faces with four equivalent K(1)Eu12 cuboctahedra, faces with four equivalent Eu(2)K4Eu8 cuboctahedra, and faces with ten equivalent Eu(1)K4Eu8 cuboctahedra. All Eu(1)-Eu(1) bond lengths are 4.13 Å. All Eu(1)-Eu(2) bond lengths are 4.20 Å. In the second Eu site, Eu(2) is bonded to four equivalent K(1) and eight equivalent Eu(1) atoms to form distorted EuK4Eu8 cuboctahedra that share corners with four equivalent Eu(2)K4Eu8 cuboctahedra, corners with eight equivalent K(1)Eu12 cuboctahedra, edges with eight equivalent Eu(2)K4Eu8 cuboctahedra, edges with sixteen equivalent Eu(1)K4Eu8 cuboctahedra, faces with four equivalent Eu(2)K4Eu8 cuboctahedra, faces with six equivalent K(1)Eu12 cuboctahedra, and faces with eight equivalent Eu(1)K4Eu8 cuboctahedra.