Mg2La crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), four equivalent Mg(1), and six equivalent La(1) atoms to form distorted MgLa6Mg6 cuboctahedra that share corners with six equivalent Mg(2)La4Mg8 cuboctahedra, corners with six equivalent Mg(1)La6Mg6 cuboctahedra, corners with six equivalent La(1)La2Mg10 cuboctahedra, edges with seven equivalent La(1)La2Mg10 cuboctahedra, edges with eleven equivalent Mg(2)La4Mg8 cuboctahedra, faces with four equivalent Mg(2)La4Mg8 cuboctahedra, faces with six equivalent La(1)La2Mg10 cuboctahedra, and faces with ten equivalent Mg(1)La6Mg6 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), six equivalent Mg(2), and four equivalent La(1) atoms to form distorted MgLa4Mg8 cuboctahedra that share corners with six equivalent Mg(2)La4Mg8 cuboctahedra, corners with six equivalent Mg(1)La6Mg6 cuboctahedra, corners with six equivalent La(1)La2Mg10 cuboctahedra, edges with three equivalent La(1)La2Mg10 cuboctahedra, edges with four equivalent Mg(2)La4Mg8 cuboctahedra, edges with eleven equivalent Mg(1)La6Mg6 cuboctahedra, faces with four equivalent Mg(1)La6Mg6 cuboctahedra, faces with eight equivalent Mg(2)La4Mg8 cuboctahedra, and faces with eight equivalent La(1)La2Mg10 cuboctahedra. La(1) is bonded to four equivalent Mg(2), six equivalent Mg(1), and two equivalent La(1) atoms to form LaLa2Mg10 cuboctahedra that share corners with six equivalent Mg(2)La4Mg8 cuboctahedra, corners with six equivalent Mg(1)La6Mg6 cuboctahedra, corners with six equivalent La(1)La2Mg10 cuboctahedra, edges with three equivalent Mg(2)La4Mg8 cuboctahedra, edges with seven equivalent Mg(1)La6Mg6 cuboctahedra, edges with eight equivalent La(1)La2Mg10 cuboctahedra, faces with six equivalent Mg(1)La6Mg6 cuboctahedra, faces with six equivalent La(1)La2Mg10 cuboctahedra, and faces with eight equivalent Mg(2)La4Mg8 cuboctahedra.
Mg2La crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), four equivalent Mg(1), and six equivalent La(1) atoms to form distorted MgLa6Mg6 cuboctahedra that share corners with six equivalent Mg(2)La4Mg8 cuboctahedra, corners with six equivalent Mg(1)La6Mg6 cuboctahedra, corners with six equivalent La(1)La2Mg10 cuboctahedra, edges with seven equivalent La(1)La2Mg10 cuboctahedra, edges with eleven equivalent Mg(2)La4Mg8 cuboctahedra, faces with four equivalent Mg(2)La4Mg8 cuboctahedra, faces with six equivalent La(1)La2Mg10 cuboctahedra, and faces with ten equivalent Mg(1)La6Mg6 cuboctahedra. Both Mg(1)-Mg(2) bond lengths are 3.38 Å. There are two shorter (3.39 Å) and two longer (3.48 Å) Mg(1)-Mg(1) bond lengths. All Mg(1)-La(1) bond lengths are 3.43 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), six equivalent Mg(2), and four equivalent La(1) atoms to form distorted MgLa4Mg8 cuboctahedra that share corners with six equivalent Mg(2)La4Mg8 cuboctahedra, corners with six equivalent Mg(1)La6Mg6 cuboctahedra, corners with six equivalent La(1)La2Mg10 cuboctahedra, edges with three equivalent La(1)La2Mg10 cuboctahedra, edges with four equivalent Mg(2)La4Mg8 cuboctahedra, edges with eleven equivalent Mg(1)La6Mg6 cuboctahedra, faces with four equivalent Mg(1)La6Mg6 cuboctahedra, faces with eight equivalent Mg(2)La4Mg8 cuboctahedra, and faces with eight equivalent La(1)La2Mg10 cuboctahedra. There are two shorter (3.39 Å) and four longer (3.47 Å) Mg(2)-Mg(2) bond lengths. There are two shorter (3.45 Å) and two longer (3.50 Å) Mg(2)-La(1) bond lengths. La(1) is bonded to four equivalent Mg(2), six equivalent Mg(1), and two equivalent La(1) atoms to form LaLa2Mg10 cuboctahedra that share corners with six equivalent Mg(2)La4Mg8 cuboctahedra, corners with six equivalent Mg(1)La6Mg6 cuboctahedra, corners with six equivalent La(1)La2Mg10 cuboctahedra, edges with three equivalent Mg(2)La4Mg8 cuboctahedra, edges with seven equivalent Mg(1)La6Mg6 cuboctahedra, edges with eight equivalent La(1)La2Mg10 cuboctahedra, faces with six equivalent Mg(1)La6Mg6 cuboctahedra, faces with six equivalent La(1)La2Mg10 cuboctahedra, and faces with eight equivalent Mg(2)La4Mg8 cuboctahedra. Both La(1)-La(1) bond lengths are 3.39 Å.