Mg6LaY crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 8-coordinate geometry to two equivalent Mg(3), two equivalent Mg(4), two equivalent La(1), and two equivalent Y(1) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to two equivalent Mg(3), two equivalent Mg(4), two equivalent La(1), and two equivalent Y(1) atoms. In the third Mg site, Mg(3) is bonded to four equivalent Mg(1), four equivalent Mg(2), two equivalent La(1), and two equivalent Y(1) atoms to form MgLa2Y2Mg8 cuboctahedra that share corners with four equivalent Mg(3)La2Y2Mg8 cuboctahedra, corners with eight equivalent Mg(4)La2Y2Mg8 cuboctahedra, edges with four equivalent La(1)Mg12 cuboctahedra, edges with four equivalent Y(1)Mg12 cuboctahedra, faces with two equivalent Mg(3)La2Y2Mg8 cuboctahedra, faces with two equivalent La(1)Mg12 cuboctahedra, faces with two equivalent Y(1)Mg12 cuboctahedra, and faces with four equivalent Mg(4)La2Y2Mg8 cuboctahedra. In the fourth Mg site, Mg(4) is bonded to four equivalent Mg(1), four equivalent Mg(2), two equivalent La(1), and two equivalent Y(1) atoms to form MgLa2Y2Mg8 cuboctahedra that share corners with four equivalent Mg(4)La2Y2Mg8 cuboctahedra, corners with eight equivalent Mg(3)La2Y2Mg8 cuboctahedra, edges with four equivalent La(1)Mg12 cuboctahedra, edges with four equivalent Y(1)Mg12 cuboctahedra, faces with two equivalent Mg(4)La2Y2Mg8 cuboctahedra, faces with two equivalent La(1)Mg12 cuboctahedra, faces with two equivalent Y(1)Mg12 cuboctahedra, and faces with four equivalent Mg(3)La2Y2Mg8 cuboctahedra. La(1) is bonded to two equivalent Mg(3), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted LaMg12 cuboctahedra that share corners with four equivalent La(1)Mg12 cuboctahedra, corners with eight equivalent Y(1)Mg12 cuboctahedra, edges with four equivalent Mg(3)La2Y2Mg8 cuboctahedra, edges with four equivalent Mg(4)La2Y2Mg8 cuboctahedra, faces with two equivalent Mg(3)La2Y2Mg8 cuboctahedra, faces with two equivalent Mg(4)La2Y2Mg8 cuboctahedra, faces with two equivalent La(1)Mg12 cuboctahedra, and faces with four equivalent Y(1)Mg12 cuboctahedra. Y(1) is bonded to two equivalent Mg(3), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted YMg12 cuboctahedra that share corners with four equivalent Y(1)Mg12 cuboctahedra, corners with eight equivalent La(1)Mg12 cuboctahedra, edges with four equivalent Mg(3)La2Y2Mg8 cuboctahedra, edges with four equivalent Mg(4)La2Y2Mg8 cuboctahedra, faces with two equivalent Mg(3)La2Y2Mg8 cuboctahedra, faces with two equivalent Mg(4)La2Y2Mg8 cuboctahedra, faces with two equivalent Y(1)Mg12 cuboctahedra, and faces with four equivalent La(1)Mg12 cuboctahedra.
Mg6LaY crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 8-coordinate geometry to two equivalent Mg(3), two equivalent Mg(4), two equivalent La(1), and two equivalent Y(1) atoms. Both Mg(1)-Mg(3) bond lengths are 3.31 Å. Both Mg(1)-Mg(4) bond lengths are 3.24 Å. Both Mg(1)-La(1) bond lengths are 3.28 Å. There is one shorter (3.27 Å) and one longer (3.30 Å) Mg(1)-Y(1) bond length. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to two equivalent Mg(3), two equivalent Mg(4), two equivalent La(1), and two equivalent Y(1) atoms. There is one shorter (3.25 Å) and one longer (3.31 Å) Mg(2)-Mg(3) bond length. There is one shorter (3.17 Å) and one longer (3.39 Å) Mg(2)-Mg(4) bond length. Both Mg(2)-La(1) bond lengths are 3.34 Å. Both Mg(2)-Y(1) bond lengths are 3.22 Å. In the third Mg site, Mg(3) is bonded to four equivalent Mg(1), four equivalent Mg(2), two equivalent La(1), and two equivalent Y(1) atoms to form MgLa2Y2Mg8 cuboctahedra that share corners with four equivalent Mg(3)La2Y2Mg8 cuboctahedra, corners with eight equivalent Mg(4)La2Y2Mg8 cuboctahedra, edges with four equivalent La(1)Mg12 cuboctahedra, edges with four equivalent Y(1)Mg12 cuboctahedra, faces with two equivalent Mg(3)La2Y2Mg8 cuboctahedra, faces with two equivalent La(1)Mg12 cuboctahedra, faces with two equivalent Y(1)Mg12 cuboctahedra, and faces with four equivalent Mg(4)La2Y2Mg8 cuboctahedra. Both Mg(3)-La(1) bond lengths are 3.55 Å. Both Mg(3)-Y(1) bond lengths are 3.51 Å. In the fourth Mg site, Mg(4) is bonded to four equivalent Mg(1), four equivalent Mg(2), two equivalent La(1), and two equivalent Y(1) atoms to form MgLa2Y2Mg8 cuboctahedra that share corners with four equivalent Mg(4)La2Y2Mg8 cuboctahedra, corners with eight equivalent Mg(3)La2Y2Mg8 cuboctahedra, edges with four equivalent La(1)Mg12 cuboctahedra, edges with four equivalent Y(1)Mg12 cuboctahedra, faces with two equivalent Mg(4)La2Y2Mg8 cuboctahedra, faces with two equivalent La(1)Mg12 cuboctahedra, faces with two equivalent Y(1)Mg12 cuboctahedra, and faces with four equivalent Mg(3)La2Y2Mg8 cuboctahedra. Both Mg(4)-La(1) bond lengths are 3.57 Å. Both Mg(4)-Y(1) bond lengths are 3.59 Å. La(1) is bonded to two equivalent Mg(3), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted LaMg12 cuboctahedra that share corners with four equivalent La(1)Mg12 cuboctahedra, corners with eight equivalent Y(1)Mg12 cuboctahedra, edges with four equivalent Mg(3)La2Y2Mg8 cuboctahedra, edges with four equivalent Mg(4)La2Y2Mg8 cuboctahedra, faces with two equivalent Mg(3)La2Y2Mg8 cuboctahedra, faces with two equivalent Mg(4)La2Y2Mg8 cuboctahedra, faces with two equivalent La(1)Mg12 cuboctahedra, and faces with four equivalent Y(1)Mg12 cuboctahedra. Y(1) is bonded to two equivalent Mg(3), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted YMg12 cuboctahedra that share corners with four equivalent Y(1)Mg12 cuboctahedra, corners with eight equivalent La(1)Mg12 cuboctahedra, edges with four equivalent Mg(3)La2Y2Mg8 cuboctahedra, edges with four equivalent Mg(4)La2Y2Mg8 cuboctahedra, faces with two equivalent Mg(3)La2Y2Mg8 cuboctahedra, faces with two equivalent Mg(4)La2Y2Mg8 cuboctahedra, faces with two equivalent Y(1)Mg12 cuboctahedra, and faces with four equivalent La(1)Mg12 cuboctahedra.