Sr3Lu1 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to four equivalent Sr(1), four equivalent Sr(2), and four equivalent Lu(1) atoms to form SrSr8Lu4 cuboctahedra that share corners with twelve equivalent Sr(1)Sr8Lu4 cuboctahedra, edges with eight equivalent Sr(1)Sr8Lu4 cuboctahedra, edges with eight equivalent Sr(2)Sr8Lu4 cuboctahedra, edges with eight equivalent Lu(1)Sr12 cuboctahedra, faces with four equivalent Sr(2)Sr8Lu4 cuboctahedra, faces with four equivalent Lu(1)Sr12 cuboctahedra, and faces with ten equivalent Sr(1)Sr8Lu4 cuboctahedra. In the second Sr site, Sr(2) is bonded to eight equivalent Sr(1) and four equivalent Lu(1) atoms to form SrSr8Lu4 cuboctahedra that share corners with four equivalent Sr(2)Sr8Lu4 cuboctahedra, corners with eight equivalent Lu(1)Sr12 cuboctahedra, edges with eight equivalent Sr(2)Sr8Lu4 cuboctahedra, edges with sixteen equivalent Sr(1)Sr8Lu4 cuboctahedra, faces with four equivalent Sr(2)Sr8Lu4 cuboctahedra, faces with six equivalent Lu(1)Sr12 cuboctahedra, and faces with eight equivalent Sr(1)Sr8Lu4 cuboctahedra. Lu(1) is bonded to four equivalent Sr(2) and eight equivalent Sr(1) atoms to form LuSr12 cuboctahedra that share corners with four equivalent Lu(1)Sr12 cuboctahedra, corners with eight equivalent Sr(2)Sr8Lu4 cuboctahedra, edges with eight equivalent Lu(1)Sr12 cuboctahedra, edges with sixteen equivalent Sr(1)Sr8Lu4 cuboctahedra, faces with four equivalent Lu(1)Sr12 cuboctahedra, faces with six equivalent Sr(2)Sr8Lu4 cuboctahedra, and faces with eight equivalent Sr(1)Sr8Lu4 cuboctahedra.
Sr3Lu1 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to four equivalent Sr(1), four equivalent Sr(2), and four equivalent Lu(1) atoms to form SrSr8Lu4 cuboctahedra that share corners with twelve equivalent Sr(1)Sr8Lu4 cuboctahedra, edges with eight equivalent Sr(1)Sr8Lu4 cuboctahedra, edges with eight equivalent Sr(2)Sr8Lu4 cuboctahedra, edges with eight equivalent Lu(1)Sr12 cuboctahedra, faces with four equivalent Sr(2)Sr8Lu4 cuboctahedra, faces with four equivalent Lu(1)Sr12 cuboctahedra, and faces with ten equivalent Sr(1)Sr8Lu4 cuboctahedra. All Sr(1)-Sr(1) bond lengths are 4.02 Å. All Sr(1)-Sr(2) bond lengths are 4.04 Å. All Sr(1)-Lu(1) bond lengths are 4.04 Å. In the second Sr site, Sr(2) is bonded to eight equivalent Sr(1) and four equivalent Lu(1) atoms to form SrSr8Lu4 cuboctahedra that share corners with four equivalent Sr(2)Sr8Lu4 cuboctahedra, corners with eight equivalent Lu(1)Sr12 cuboctahedra, edges with eight equivalent Sr(2)Sr8Lu4 cuboctahedra, edges with sixteen equivalent Sr(1)Sr8Lu4 cuboctahedra, faces with four equivalent Sr(2)Sr8Lu4 cuboctahedra, faces with six equivalent Lu(1)Sr12 cuboctahedra, and faces with eight equivalent Sr(1)Sr8Lu4 cuboctahedra. All Sr(2)-Lu(1) bond lengths are 4.02 Å. Lu(1) is bonded to four equivalent Sr(2) and eight equivalent Sr(1) atoms to form LuSr12 cuboctahedra that share corners with four equivalent Lu(1)Sr12 cuboctahedra, corners with eight equivalent Sr(2)Sr8Lu4 cuboctahedra, edges with eight equivalent Lu(1)Sr12 cuboctahedra, edges with sixteen equivalent Sr(1)Sr8Lu4 cuboctahedra, faces with four equivalent Lu(1)Sr12 cuboctahedra, faces with six equivalent Sr(2)Sr8Lu4 cuboctahedra, and faces with eight equivalent Sr(1)Sr8Lu4 cuboctahedra.