SrMg6La crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent La(1) atoms to form SrLa2Mg10 cuboctahedra that share corners with four equivalent Mg(4)Sr2Mg10 cuboctahedra, corners with six equivalent Sr(1)La2Mg10 cuboctahedra, edges with two equivalent Mg(4)Sr2Mg10 cuboctahedra, edges with four equivalent La(1)Sr2Mg10 cuboctahedra, faces with two equivalent Sr(1)La2Mg10 cuboctahedra, faces with two equivalent Mg(4)Sr2Mg10 cuboctahedra, faces with two equivalent La(1)Sr2Mg10 cuboctahedra, and faces with six equivalent Mg(2)La2Mg10 cuboctahedra. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 11-coordinate geometry to two equivalent Sr(1), one Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and two equivalent La(1) atoms. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent La(1) atoms to form MgLa2Mg10 cuboctahedra that share corners with four equivalent La(1)Sr2Mg10 cuboctahedra, corners with six equivalent Mg(2)La2Mg10 cuboctahedra, edges with two equivalent La(1)Sr2Mg10 cuboctahedra, edges with four equivalent Mg(4)Sr2Mg10 cuboctahedra, faces with two equivalent Mg(2)La2Mg10 cuboctahedra, faces with two equivalent Mg(4)Sr2Mg10 cuboctahedra, faces with two equivalent La(1)Sr2Mg10 cuboctahedra, and faces with six equivalent Sr(1)La2Mg10 cuboctahedra. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to two equivalent Sr(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), and two equivalent La(1) atoms. In the fourth Mg site, Mg(4) is bonded to two equivalent Sr(1), two equivalent Mg(2), four equivalent Mg(1), and four equivalent Mg(3) atoms to form MgSr2Mg10 cuboctahedra that share corners with four equivalent Sr(1)La2Mg10 cuboctahedra, corners with six equivalent Mg(4)Sr2Mg10 cuboctahedra, edges with two equivalent Sr(1)La2Mg10 cuboctahedra, edges with four equivalent Mg(2)La2Mg10 cuboctahedra, faces with two equivalent Sr(1)La2Mg10 cuboctahedra, faces with two equivalent Mg(2)La2Mg10 cuboctahedra, faces with two equivalent Mg(4)Sr2Mg10 cuboctahedra, and faces with six equivalent La(1)Sr2Mg10 cuboctahedra. La(1) is bonded to two equivalent Sr(1), two equivalent Mg(2), four equivalent Mg(1), and four equivalent Mg(3) atoms to form LaSr2Mg10 cuboctahedra that share corners with four equivalent Mg(2)La2Mg10 cuboctahedra, corners with six equivalent La(1)Sr2Mg10 cuboctahedra, edges with two equivalent Mg(2)La2Mg10 cuboctahedra, edges with four equivalent Sr(1)La2Mg10 cuboctahedra, faces with two equivalent Sr(1)La2Mg10 cuboctahedra, faces with two equivalent Mg(2)La2Mg10 cuboctahedra, faces with two equivalent La(1)Sr2Mg10 cuboctahedra, and faces with six equivalent Mg(4)Sr2Mg10 cuboctahedra.
SrMg6La crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent La(1) atoms to form SrLa2Mg10 cuboctahedra that share corners with four equivalent Mg(4)Sr2Mg10 cuboctahedra, corners with six equivalent Sr(1)La2Mg10 cuboctahedra, edges with two equivalent Mg(4)Sr2Mg10 cuboctahedra, edges with four equivalent La(1)Sr2Mg10 cuboctahedra, faces with two equivalent Sr(1)La2Mg10 cuboctahedra, faces with two equivalent Mg(4)Sr2Mg10 cuboctahedra, faces with two equivalent La(1)Sr2Mg10 cuboctahedra, and faces with six equivalent Mg(2)La2Mg10 cuboctahedra. Both Sr(1)-Mg(4) bond lengths are 3.59 Å. All Sr(1)-Mg(1) bond lengths are 3.37 Å. There are two shorter (3.33 Å) and two longer (3.52 Å) Sr(1)-Mg(3) bond lengths. Both Sr(1)-La(1) bond lengths are 3.57 Å. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 11-coordinate geometry to two equivalent Sr(1), one Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and two equivalent La(1) atoms. The Mg(1)-Mg(1) bond length is 3.52 Å. There is one shorter (3.38 Å) and one longer (3.47 Å) Mg(1)-Mg(2) bond length. Both Mg(1)-Mg(3) bond lengths are 3.39 Å. Both Mg(1)-Mg(4) bond lengths are 3.36 Å. There is one shorter (3.27 Å) and one longer (3.58 Å) Mg(1)-La(1) bond length. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent La(1) atoms to form MgLa2Mg10 cuboctahedra that share corners with four equivalent La(1)Sr2Mg10 cuboctahedra, corners with six equivalent Mg(2)La2Mg10 cuboctahedra, edges with two equivalent La(1)Sr2Mg10 cuboctahedra, edges with four equivalent Mg(4)Sr2Mg10 cuboctahedra, faces with two equivalent Mg(2)La2Mg10 cuboctahedra, faces with two equivalent Mg(4)Sr2Mg10 cuboctahedra, faces with two equivalent La(1)Sr2Mg10 cuboctahedra, and faces with six equivalent Sr(1)La2Mg10 cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.45 Å. All Mg(2)-Mg(3) bond lengths are 3.38 Å. Both Mg(2)-La(1) bond lengths are 3.59 Å. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to two equivalent Sr(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), and two equivalent La(1) atoms. There is one shorter (3.38 Å) and one longer (3.47 Å) Mg(3)-Mg(4) bond length. Both Mg(3)-La(1) bond lengths are 3.34 Å. In the fourth Mg site, Mg(4) is bonded to two equivalent Sr(1), two equivalent Mg(2), four equivalent Mg(1), and four equivalent Mg(3) atoms to form MgSr2Mg10 cuboctahedra that share corners with four equivalent Sr(1)La2Mg10 cuboctahedra, corners with six equivalent Mg(4)Sr2Mg10 cuboctahedra, edges with two equivalent Sr(1)La2Mg10 cuboctahedra, edges with four equivalent Mg(2)La2Mg10 cuboctahedra, faces with two equivalent Sr(1)La2Mg10 cuboctahedra, faces with two equivalent Mg(2)La2Mg10 cuboctahedra, faces with two equivalent Mg(4)Sr2Mg10 cuboctahedra, and faces with six equivalent La(1)Sr2Mg10 cuboctahedra. La(1) is bonded to two equivalent Sr(1), two equivalent Mg(2), four equivalent Mg(1), and four equivalent Mg(3) atoms to form LaSr2Mg10 cuboctahedra that share corners with four equivalent Mg(2)La2Mg10 cuboctahedra, corners with six equivalent La(1)Sr2Mg10 cuboctahedra, edges with two equivalent Mg(2)La2Mg10 cuboctahedra, edges with four equivalent Sr(1)La2Mg10 cuboctahedra, faces with two equivalent Sr(1)La2Mg10 cuboctahedra, faces with two equivalent Mg(2)La2Mg10 cuboctahedra, faces with two equivalent La(1)Sr2Mg10 cuboctahedra, and faces with six equivalent Mg(4)Sr2Mg10 cuboctahedra.