Mg6LaSb crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent La(1), and two equivalent Sb(1) atoms to form distorted MgLa2Mg8Sb2 cuboctahedra that share corners with four equivalent La(1)Mg10Sb2 cuboctahedra, corners with four equivalent Sb(1)La2Mg10 cuboctahedra, corners with ten equivalent Mg(1)La2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(1)La2Mg8Sb2 cuboctahedra, edges with two equivalent La(1)Mg10Sb2 cuboctahedra, edges with two equivalent Sb(1)La2Mg10 cuboctahedra, faces with two equivalent La(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)La2Mg10 cuboctahedra, and faces with four equivalent Mg(1)La2Mg8Sb2 cuboctahedra. In the second Mg site, Mg(2) is bonded in a 12-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent La(1), and two equivalent Sb(1) atoms. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent La(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 2-coordinate geometry to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sb(1) atoms. La(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sb(1) atoms to form distorted LaMg10Sb2 cuboctahedra that share corners with four equivalent Sb(1)La2Mg10 cuboctahedra, corners with six equivalent La(1)Mg10Sb2 cuboctahedra, corners with eight equivalent Mg(1)La2Mg8Sb2 cuboctahedra, edges with two equivalent Sb(1)La2Mg10 cuboctahedra, edges with four equivalent Mg(1)La2Mg8Sb2 cuboctahedra, faces with two equivalent La(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)La2Mg10 cuboctahedra, and faces with four equivalent Mg(1)La2Mg8Sb2 cuboctahedra. Sb(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent La(1) atoms to form SbLa2Mg10 cuboctahedra that share corners with four equivalent La(1)Mg10Sb2 cuboctahedra, corners with six equivalent Sb(1)La2Mg10 cuboctahedra, corners with eight equivalent Mg(1)La2Mg8Sb2 cuboctahedra, edges with two equivalent La(1)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(1)La2Mg8Sb2 cuboctahedra, faces with two equivalent La(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)La2Mg10 cuboctahedra, and faces with four equivalent Mg(1)La2Mg8Sb2 cuboctahedra.
Mg6LaSb crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent La(1), and two equivalent Sb(1) atoms to form distorted MgLa2Mg8Sb2 cuboctahedra that share corners with four equivalent La(1)Mg10Sb2 cuboctahedra, corners with four equivalent Sb(1)La2Mg10 cuboctahedra, corners with ten equivalent Mg(1)La2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(1)La2Mg8Sb2 cuboctahedra, edges with two equivalent La(1)Mg10Sb2 cuboctahedra, edges with two equivalent Sb(1)La2Mg10 cuboctahedra, faces with two equivalent La(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)La2Mg10 cuboctahedra, and faces with four equivalent Mg(1)La2Mg8Sb2 cuboctahedra. There is one shorter (3.17 Å) and one longer (3.24 Å) Mg(1)-Mg(1) bond length. Both Mg(1)-Mg(2) bond lengths are 3.28 Å. Both Mg(1)-Mg(3) bond lengths are 3.25 Å. Both Mg(1)-Mg(4) bond lengths are 3.28 Å. There is one shorter (3.35 Å) and one longer (3.42 Å) Mg(1)-La(1) bond length. There is one shorter (3.35 Å) and one longer (3.42 Å) Mg(1)-Sb(1) bond length. In the second Mg site, Mg(2) is bonded in a 12-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent La(1), and two equivalent Sb(1) atoms. There is one shorter (3.13 Å) and one longer (3.28 Å) Mg(2)-Mg(2) bond length. There is one shorter (3.23 Å) and one longer (3.53 Å) Mg(2)-Mg(3) bond length. There is one shorter (3.31 Å) and one longer (3.46 Å) Mg(2)-Mg(4) bond length. Both Mg(2)-La(1) bond lengths are 3.33 Å. Both Mg(2)-Sb(1) bond lengths are 3.28 Å. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent La(1) atoms. Both Mg(3)-Mg(4) bond lengths are 3.21 Å. Both Mg(3)-La(1) bond lengths are 3.35 Å. In the fourth Mg site, Mg(4) is bonded in a 2-coordinate geometry to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sb(1) atoms. Both Mg(4)-Sb(1) bond lengths are 3.36 Å. La(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sb(1) atoms to form distorted LaMg10Sb2 cuboctahedra that share corners with four equivalent Sb(1)La2Mg10 cuboctahedra, corners with six equivalent La(1)Mg10Sb2 cuboctahedra, corners with eight equivalent Mg(1)La2Mg8Sb2 cuboctahedra, edges with two equivalent Sb(1)La2Mg10 cuboctahedra, edges with four equivalent Mg(1)La2Mg8Sb2 cuboctahedra, faces with two equivalent La(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)La2Mg10 cuboctahedra, and faces with four equivalent Mg(1)La2Mg8Sb2 cuboctahedra. Both La(1)-Sb(1) bond lengths are 3.21 Å. Sb(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent La(1) atoms to form SbLa2Mg10 cuboctahedra that share corners with four equivalent La(1)Mg10Sb2 cuboctahedra, corners with six equivalent Sb(1)La2Mg10 cuboctahedra, corners with eight equivalent Mg(1)La2Mg8Sb2 cuboctahedra, edges with two equivalent La(1)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(1)La2Mg8Sb2 cuboctahedra, faces with two equivalent La(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)La2Mg10 cuboctahedra, and faces with four equivalent Mg(1)La2Mg8Sb2 cuboctahedra.