Li3Mg is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Li(1) is bonded to eight equivalent Li(1) and four equivalent Mg(1) atoms to form LiLi8Mg4 cuboctahedra that share corners with four equivalent Mg(1)Li12 cuboctahedra, corners with fourteen equivalent Li(1)Li8Mg4 cuboctahedra, edges with six equivalent Mg(1)Li12 cuboctahedra, edges with twelve equivalent Li(1)Li8Mg4 cuboctahedra, faces with four equivalent Mg(1)Li12 cuboctahedra, and faces with sixteen equivalent Li(1)Li8Mg4 cuboctahedra. Mg(1) is bonded to twelve equivalent Li(1) atoms to form MgLi12 cuboctahedra that share corners with six equivalent Mg(1)Li12 cuboctahedra, corners with twelve equivalent Li(1)Li8Mg4 cuboctahedra, edges with eighteen equivalent Li(1)Li8Mg4 cuboctahedra, faces with eight equivalent Mg(1)Li12 cuboctahedra, and faces with twelve equivalent Li(1)Li8Mg4 cuboctahedra.
Li3Mg is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Li(1) is bonded to eight equivalent Li(1) and four equivalent Mg(1) atoms to form LiLi8Mg4 cuboctahedra that share corners with four equivalent Mg(1)Li12 cuboctahedra, corners with fourteen equivalent Li(1)Li8Mg4 cuboctahedra, edges with six equivalent Mg(1)Li12 cuboctahedra, edges with twelve equivalent Li(1)Li8Mg4 cuboctahedra, faces with four equivalent Mg(1)Li12 cuboctahedra, and faces with sixteen equivalent Li(1)Li8Mg4 cuboctahedra. There are a spread of Li(1)-Li(1) bond distances ranging from 3.04-3.06 Å. There are two shorter (3.05 Å) and two longer (3.06 Å) Li(1)-Mg(1) bond lengths. Mg(1) is bonded to twelve equivalent Li(1) atoms to form MgLi12 cuboctahedra that share corners with six equivalent Mg(1)Li12 cuboctahedra, corners with twelve equivalent Li(1)Li8Mg4 cuboctahedra, edges with eighteen equivalent Li(1)Li8Mg4 cuboctahedra, faces with eight equivalent Mg(1)Li12 cuboctahedra, and faces with twelve equivalent Li(1)Li8Mg4 cuboctahedra.