Li3Mg is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to eight equivalent Li(2) and four equivalent Mg(1) atoms to form LiLi8Mg4 cuboctahedra that share corners with four equivalent Li(1)Li8Mg4 cuboctahedra, corners with eight equivalent Mg(1)Li12 cuboctahedra, edges with eight equivalent Li(1)Li8Mg4 cuboctahedra, edges with sixteen equivalent Li(2)Li8Mg4 cuboctahedra, faces with four equivalent Li(1)Li8Mg4 cuboctahedra, faces with six equivalent Mg(1)Li12 cuboctahedra, and faces with eight equivalent Li(2)Li8Mg4 cuboctahedra. In the second Li site, Li(2) is bonded to four equivalent Li(1), four equivalent Li(2), and four equivalent Mg(1) atoms to form LiLi8Mg4 cuboctahedra that share corners with twelve equivalent Li(2)Li8Mg4 cuboctahedra, edges with eight equivalent Li(1)Li8Mg4 cuboctahedra, edges with eight equivalent Li(2)Li8Mg4 cuboctahedra, edges with eight equivalent Mg(1)Li12 cuboctahedra, faces with four equivalent Li(1)Li8Mg4 cuboctahedra, faces with four equivalent Mg(1)Li12 cuboctahedra, and faces with ten equivalent Li(2)Li8Mg4 cuboctahedra. Mg(1) is bonded to four equivalent Li(1) and eight equivalent Li(2) atoms to form MgLi12 cuboctahedra that share corners with four equivalent Mg(1)Li12 cuboctahedra, corners with eight equivalent Li(1)Li8Mg4 cuboctahedra, edges with eight equivalent Mg(1)Li12 cuboctahedra, edges with sixteen equivalent Li(2)Li8Mg4 cuboctahedra, faces with four equivalent Mg(1)Li12 cuboctahedra, faces with six equivalent Li(1)Li8Mg4 cuboctahedra, and faces with eight equivalent Li(2)Li8Mg4 cuboctahedra.
Li3Mg is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to eight equivalent Li(2) and four equivalent Mg(1) atoms to form LiLi8Mg4 cuboctahedra that share corners with four equivalent Li(1)Li8Mg4 cuboctahedra, corners with eight equivalent Mg(1)Li12 cuboctahedra, edges with eight equivalent Li(1)Li8Mg4 cuboctahedra, edges with sixteen equivalent Li(2)Li8Mg4 cuboctahedra, faces with four equivalent Li(1)Li8Mg4 cuboctahedra, faces with six equivalent Mg(1)Li12 cuboctahedra, and faces with eight equivalent Li(2)Li8Mg4 cuboctahedra. All Li(1)-Li(2) bond lengths are 3.04 Å. All Li(1)-Mg(1) bond lengths are 3.05 Å. In the second Li site, Li(2) is bonded to four equivalent Li(1), four equivalent Li(2), and four equivalent Mg(1) atoms to form LiLi8Mg4 cuboctahedra that share corners with twelve equivalent Li(2)Li8Mg4 cuboctahedra, edges with eight equivalent Li(1)Li8Mg4 cuboctahedra, edges with eight equivalent Li(2)Li8Mg4 cuboctahedra, edges with eight equivalent Mg(1)Li12 cuboctahedra, faces with four equivalent Li(1)Li8Mg4 cuboctahedra, faces with four equivalent Mg(1)Li12 cuboctahedra, and faces with ten equivalent Li(2)Li8Mg4 cuboctahedra. All Li(2)-Li(2) bond lengths are 3.05 Å. All Li(2)-Mg(1) bond lengths are 3.04 Å. Mg(1) is bonded to four equivalent Li(1) and eight equivalent Li(2) atoms to form MgLi12 cuboctahedra that share corners with four equivalent Mg(1)Li12 cuboctahedra, corners with eight equivalent Li(1)Li8Mg4 cuboctahedra, edges with eight equivalent Mg(1)Li12 cuboctahedra, edges with sixteen equivalent Li(2)Li8Mg4 cuboctahedra, faces with four equivalent Mg(1)Li12 cuboctahedra, faces with six equivalent Li(1)Li8Mg4 cuboctahedra, and faces with eight equivalent Li(2)Li8Mg4 cuboctahedra.