Mg2La crystallizes in the hexagonal P-62m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 8-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), and four equivalent La(1) atoms. In the second Mg site, Mg(2) is bonded to six equivalent Mg(1) and six equivalent La(1) atoms to form MgLa6Mg6 cuboctahedra that share corners with eighteen equivalent La(1)La3Mg9 cuboctahedra, edges with six equivalent Mg(2)La6Mg6 cuboctahedra, faces with two equivalent Mg(2)La6Mg6 cuboctahedra, and faces with six equivalent La(1)La3Mg9 cuboctahedra. La(1) is bonded to three equivalent Mg(2), six equivalent Mg(1), and three equivalent La(1) atoms to form LaLa3Mg9 cuboctahedra that share corners with nine equivalent Mg(2)La6Mg6 cuboctahedra, corners with nine equivalent La(1)La3Mg9 cuboctahedra, edges with six equivalent La(1)La3Mg9 cuboctahedra, faces with three equivalent Mg(2)La6Mg6 cuboctahedra, and faces with five equivalent La(1)La3Mg9 cuboctahedra.
Mg2La crystallizes in the hexagonal P-62m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 8-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), and four equivalent La(1) atoms. Both Mg(1)-Mg(1) bond lengths are 3.16 Å. Both Mg(1)-Mg(2) bond lengths are 3.24 Å. All Mg(1)-La(1) bond lengths are 3.42 Å. In the second Mg site, Mg(2) is bonded to six equivalent Mg(1) and six equivalent La(1) atoms to form MgLa6Mg6 cuboctahedra that share corners with eighteen equivalent La(1)La3Mg9 cuboctahedra, edges with six equivalent Mg(2)La6Mg6 cuboctahedra, faces with two equivalent Mg(2)La6Mg6 cuboctahedra, and faces with six equivalent La(1)La3Mg9 cuboctahedra. All Mg(2)-La(1) bond lengths are 3.51 Å. La(1) is bonded to three equivalent Mg(2), six equivalent Mg(1), and three equivalent La(1) atoms to form LaLa3Mg9 cuboctahedra that share corners with nine equivalent Mg(2)La6Mg6 cuboctahedra, corners with nine equivalent La(1)La3Mg9 cuboctahedra, edges with six equivalent La(1)La3Mg9 cuboctahedra, faces with three equivalent Mg(2)La6Mg6 cuboctahedra, and faces with five equivalent La(1)La3Mg9 cuboctahedra. All La(1)-La(1) bond lengths are 3.51 Å.