SrMg14La crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded to two equivalent Mg(7), four equivalent Mg(3), four equivalent Mg(5), and two equivalent La(1) atoms to form SrLa2Mg10 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra; corners with six equivalent Sr(1)La2Mg10 cuboctahedra; corners with eight equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent La(1)Sr2Mg10 cuboctahedra; edges with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra; edges with four equivalent Mg(7)SrMg11 cuboctahedra; edges with eight Mg(5,5)SrLaMg10 cuboctahedra; faces with two equivalent Mg(2)Mg12 cuboctahedra; faces with two equivalent Mg(7)SrMg11 cuboctahedra; faces with two equivalent La(1)Sr2Mg10 cuboctahedra; faces with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra; faces with four equivalent Mg(5)SrLaMg10 cuboctahedra; and faces with six equivalent Mg(6)LaMg11 cuboctahedra. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(6), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Sr(1)La2Mg10 cuboctahedra; corners with six equivalent Mg(1)Mg12 cuboctahedra; corners with eight equivalent Mg(3)Sr2La2Mg8 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with four equivalent Mg(6)LaMg11 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight Mg(5,5)SrLaMg10 cuboctahedra; faces with two equivalent Mg(6)LaMg11 cuboctahedra; faces with two equivalent Mg(2)Mg12 cuboctahedra; faces with two equivalent La(1)Sr2Mg10 cuboctahedra; faces with four equivalent Mg(4)Mg12 cuboctahedra; faces with four equivalent Mg(5)SrLaMg10 cuboctahedra; and faces with six equivalent Mg(7)SrMg11 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(7), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent La(1)Sr2Mg10 cuboctahedra; corners with six equivalent Mg(2)Mg12 cuboctahedra; corners with eight equivalent Mg(3)Sr2La2Mg8 cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with four equivalent Mg(7)SrMg11 cuboctahedra; edges with eight Mg(5,5)SrLaMg10 cuboctahedra; faces with two equivalent Sr(1)La2Mg10 cuboctahedra; faces with two equivalent Mg(1)Mg12 cuboctahedra; faces with two equivalent Mg(7)SrMg11 cuboctahedra; faces with four equivalent Mg(4)Mg12 cuboctahedra; faces with four equivalent Mg(5)SrLaMg10 cuboctahedra; and faces with six equivalent Mg(6)LaMg11 cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent Sr(1), two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), and two equivalent La(1) atoms to form distorted MgSr2La2Mg8 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with four equivalent Mg(4)Mg12 cuboctahedra, corners with six equivalent Mg(3)Sr2La2Mg8 cuboctahedra, edges with two equivalent Sr(1)La2Mg10 cuboctahedra, edges with two equivalent Mg(3)Sr2La2Mg8 cuboctahedra, edges with two equivalent La(1)Sr2Mg10 cuboctahedra, edges with four equivalent Mg(6)LaMg11 cuboctahedra, edges with four equivalent Mg(5)SrLaMg10 cuboctahedra, edges with four equivalent Mg(7)SrMg11 cuboctahedra, faces with two equivalent Sr(1)La2Mg10 cuboctahedra, faces with two equivalent Mg(6)LaMg11 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Sr2La2Mg8 cuboctahedra, faces with two equivalent Mg(7)SrMg11 cuboctahedra, faces with two equivalent La(1)Sr2Mg10 cuboctahedra, and faces with eight equivalent Mg(5)SrLaMg10 cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Sr(1)La2Mg10 cuboctahedra, corners with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra, corners with four equivalent La(1)Sr2Mg10 cuboctahedra, corners with six equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(6)LaMg11 cuboctahedra, edges with four equivalent Mg(5)SrLaMg10 cuboctahedra, edges with four equivalent Mg(7)SrMg11 cuboctahedra, faces with two equivalent Mg(6)LaMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Sr2La2Mg8 cuboctahedra, faces with two equivalent Mg(7)SrMg11 cuboctahedra, and faces with eight equivalent Mg(5)SrLaMg10 cuboctahedra. In the fifth Mg site, Mg(5) is bonded to one Sr(1), one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), and one La(1) atom to form distorted MgSrLaMg10 cuboctahedra that share corners with four equivalent Mg(6)LaMg11 cuboctahedra; corners with four equivalent Mg(7)SrMg11 cuboctahedra; corners with ten Mg(5,5)SrLaMg10 cuboctahedra; edges with two equivalent Sr(1)La2Mg10 cuboctahedra; edges with two equivalent Mg(6)LaMg11 cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Mg(3)Sr2La2Mg8 cuboctahedra; edges with two equivalent Mg(5)SrLaMg10 cuboctahedra; edges with two equivalent Mg(7)SrMg11 cuboctahedra; edges with two equivalent La(1)Sr2Mg10 cuboctahedra;  a faceface with one Sr(1)La2Mg10 cuboctahedra;  a faceface with one Mg(1)Mg12 cuboctahedra;  a faceface with one Mg(2)Mg12 cuboctahedra;  a faceface with one La(1)Sr2Mg10 cuboctahedra; faces with two equivalent Mg(6)LaMg11 cuboctahedra; faces with two equivalent Mg(7)SrMg11 cuboctahedra; faces with four equivalent Mg(4)Mg12 cuboctahedra; faces with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra; and faces with four equivalent Mg(5)SrLaMg10 cuboctahedra. In the sixth Mg site, Mg(6) is bonded to one Mg(1); two equivalent Mg(3); two equivalent Mg(4); two equivalent Mg(7); four Mg(5,5); and one La(1) atom to form distorted MgLaMg11 cuboctahedra that share corners with four equivalent Mg(7)SrMg11 cuboctahedra; corners with six equivalent Mg(6)LaMg11 cuboctahedra; corners with eight Mg(5,5)SrLaMg10 cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mg(7)SrMg11 cuboctahedra; edges with two equivalent La(1)Sr2Mg10 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra; edges with four Mg(5,5)SrLaMg10 cuboctahedra;  a faceface with one Mg(1)Mg12 cuboctahedra;  a faceface with one La(1)Sr2Mg10 cuboctahedra; faces with two equivalent Mg(6)LaMg11 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(3)Sr2La2Mg8 cuboctahedra; faces with two equivalent Mg(7)SrMg11 cuboctahedra; faces with three equivalent Sr(1)La2Mg10 cuboctahedra; faces with three equivalent Mg(2)Mg12 cuboctahedra; and faces with four Mg(5,5)SrLaMg10 cuboctahedra. In the seventh Mg site, Mg(7) is bonded to one Sr(1); one Mg(2); two equivalent Mg(3); two equivalent Mg(4); two equivalent Mg(6); and four Mg(5,5) atoms to form distorted MgSrMg11 cuboctahedra that share corners with four equivalent Mg(6)LaMg11 cuboctahedra; corners with six equivalent Mg(7)SrMg11 cuboctahedra; corners with eight Mg(5,5)SrLaMg10 cuboctahedra; edges with two equivalent Sr(1)La2Mg10 cuboctahedra; edges with two equivalent Mg(6)LaMg11 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra; edges with four Mg(5,5)SrLaMg10 cuboctahedra;  a faceface with one Sr(1)La2Mg10 cuboctahedra;  a faceface with one Mg(2)Mg12 cuboctahedra; faces with two equivalent Mg(6)LaMg11 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(3)Sr2La2Mg8 cuboctahedra; faces with two equivalent Mg(7)SrMg11 cuboctahedra; faces with three equivalent Mg(1)Mg12 cuboctahedra; faces with three equivalent La(1)Sr2Mg10 cuboctahedra; and faces with four Mg(5,5)SrLaMg10 cuboctahedra. In the eighth Mg site, Mg(5) is bonded to one Sr(1), one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), and one La(1) atom to form distorted MgSrLaMg10 cuboctahedra that share corners with four equivalent Mg(6)LaMg11 cuboctahedra; corners with four equivalent Mg(7)SrMg11 cuboctahedra; corners with ten Mg(5,5)SrLaMg10 cuboctahedra; edges with two equivalent Sr(1)La2Mg10 cuboctahedra; edges with two equivalent Mg(6)LaMg11 cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Mg(3)Sr2La2Mg8 cuboctahedra; edges with two equivalent Mg(5)SrLaMg10 cuboctahedra; edges with two equivalent Mg(7)SrMg11 cuboctahedra; edges with two equivalent La(1)Sr2Mg10 cuboctahedra;  a faceface with one Sr(1)La2Mg10 cuboctahedra;  a faceface with one Mg(1)Mg12 cuboctahedra;  a faceface with one Mg(2)Mg12 cuboctahedra;  a faceface with one La(1)Sr2Mg10 cuboctahedra; faces with two equivalent Mg(6)LaMg11 cuboctahedra; faces with two equivalent Mg(7)SrMg11 cuboctahedra; faces with four equivalent Mg(4)Mg12 cuboctahedra; faces with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra; and faces with four Mg(5,5)SrLaMg10 cuboctahedra. La(1) is bonded to two equivalent Sr(1), two equivalent Mg(6), four equivalent Mg(3), and four equivalent Mg(5) atoms to form LaSr2Mg10 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra; corners with six equivalent La(1)Sr2Mg10 cuboctahedra; corners with eight equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Sr(1)La2Mg10 cuboctahedra; edges with four equivalent Mg(6)LaMg11 cuboctahedra; edges with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra; edges with eight Mg(5,5)SrLaMg10 cuboctahedra; faces with two equivalent Sr(1)La2Mg10 cuboctahedra; faces with two equivalent Mg(6)LaMg11 cuboctahedra; faces with two equivalent Mg(1)Mg12 cuboctahedra; faces with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra; faces with four equivalent Mg(5)SrLaMg10 cuboctahedra; and faces with six equivalent Mg(7)SrMg11 cuboctahedra.
SrMg14La crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded to two equivalent Mg(7), four equivalent Mg(3), four equivalent Mg(5), and two equivalent La(1) atoms to form SrLa2Mg10 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra; corners with six equivalent Sr(1)La2Mg10 cuboctahedra; corners with eight equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent La(1)Sr2Mg10 cuboctahedra; edges with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra; edges with four equivalent Mg(7)SrMg11 cuboctahedra; edges with eight Mg(5,5)SrLaMg10 cuboctahedra; faces with two equivalent Mg(2)Mg12 cuboctahedra; faces with two equivalent Mg(7)SrMg11 cuboctahedra; faces with two equivalent La(1)Sr2Mg10 cuboctahedra; faces with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra; faces with four equivalent Mg(5)SrLaMg10 cuboctahedra; and faces with six equivalent Mg(6)LaMg11 cuboctahedra. Both Sr(1)-Mg(7) bond lengths are 3.40 Å. There are two shorter (3.32 Å) and two longer (3.39 Å) Sr(1)-Mg(3) bond lengths. All Sr(1)-Mg(5) bond lengths are 3.43 Å. Both Sr(1)-La(1) bond lengths are 3.33 Å. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(6), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Sr(1)La2Mg10 cuboctahedra; corners with six equivalent Mg(1)Mg12 cuboctahedra; corners with eight equivalent Mg(3)Sr2La2Mg8 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with four equivalent Mg(6)LaMg11 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight Mg(5,5)SrLaMg10 cuboctahedra; faces with two equivalent Mg(6)LaMg11 cuboctahedra; faces with two equivalent Mg(2)Mg12 cuboctahedra; faces with two equivalent La(1)Sr2Mg10 cuboctahedra; faces with four equivalent Mg(4)Mg12 cuboctahedra; faces with four equivalent Mg(5)SrLaMg10 cuboctahedra; and faces with six equivalent Mg(7)SrMg11 cuboctahedra. Both Mg(1)-Mg(2) bond lengths are 3.33 Å. Both Mg(1)-Mg(6) bond lengths are 3.27 Å. There are two shorter (3.34 Å) and two longer (3.37 Å) Mg(1)-Mg(4) bond lengths. All Mg(1)-Mg(5) bond lengths are 3.17 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(7), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent La(1)Sr2Mg10 cuboctahedra; corners with six equivalent Mg(2)Mg12 cuboctahedra; corners with eight equivalent Mg(3)Sr2La2Mg8 cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with four equivalent Mg(7)SrMg11 cuboctahedra; edges with eight Mg(5,5)SrLaMg10 cuboctahedra; faces with two equivalent Sr(1)La2Mg10 cuboctahedra; faces with two equivalent Mg(1)Mg12 cuboctahedra; faces with two equivalent Mg(7)SrMg11 cuboctahedra; faces with four equivalent Mg(4)Mg12 cuboctahedra; faces with four equivalent Mg(5)SrLaMg10 cuboctahedra; and faces with six equivalent Mg(6)LaMg11 cuboctahedra. Both Mg(2)-Mg(7) bond lengths are 3.27 Å. There are two shorter (3.34 Å) and two longer (3.36 Å) Mg(2)-Mg(4) bond lengths. All Mg(2)-Mg(5) bond lengths are 3.18 Å. In the third Mg site, Mg(3) is bonded to two equivalent Sr(1), two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), and two equivalent La(1) atoms to form distorted MgSr2La2Mg8 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with four equivalent Mg(4)Mg12 cuboctahedra, corners with six equivalent Mg(3)Sr2La2Mg8 cuboctahedra, edges with two equivalent Sr(1)La2Mg10 cuboctahedra, edges with two equivalent Mg(3)Sr2La2Mg8 cuboctahedra, edges with two equivalent La(1)Sr2Mg10 cuboctahedra, edges with four equivalent Mg(6)LaMg11 cuboctahedra, edges with four equivalent Mg(5)SrLaMg10 cuboctahedra, edges with four equivalent Mg(7)SrMg11 cuboctahedra, faces with two equivalent Sr(1)La2Mg10 cuboctahedra, faces with two equivalent Mg(6)LaMg11 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Sr2La2Mg8 cuboctahedra, faces with two equivalent Mg(7)SrMg11 cuboctahedra, faces with two equivalent La(1)Sr2Mg10 cuboctahedra, and faces with eight equivalent Mg(5)SrLaMg10 cuboctahedra. There is one shorter (3.32 Å) and one longer (3.35 Å) Mg(3)-Mg(3) bond length. Both Mg(3)-Mg(5) bond lengths are 3.40 Å. Both Mg(3)-Mg(6) bond lengths are 3.32 Å. Both Mg(3)-Mg(7) bond lengths are 3.34 Å. There is one shorter (3.32 Å) and one longer (3.39 Å) Mg(3)-La(1) bond length. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Sr(1)La2Mg10 cuboctahedra, corners with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra, corners with four equivalent La(1)Sr2Mg10 cuboctahedra, corners with six equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(6)LaMg11 cuboctahedra, edges with four equivalent Mg(5)SrLaMg10 cuboctahedra, edges with four equivalent Mg(7)SrMg11 cuboctahedra, faces with two equivalent Mg(6)LaMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Sr2La2Mg8 cuboctahedra, faces with two equivalent Mg(7)SrMg11 cuboctahedra, and faces with eight equivalent Mg(5)SrLaMg10 cuboctahedra. There is one shorter (3.33 Å) and one longer (3.34 Å) Mg(4)-Mg(4) bond length. Both Mg(4)-Mg(5) bond lengths are 3.15 Å. Both Mg(4)-Mg(6) bond lengths are 3.24 Å. Both Mg(4)-Mg(7) bond lengths are 3.22 Å. In the fifth Mg site, Mg(5) is bonded to one Sr(1), one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), and one La(1) atom to form distorted MgSrLaMg10 cuboctahedra that share corners with four equivalent Mg(6)LaMg11 cuboctahedra; corners with four equivalent Mg(7)SrMg11 cuboctahedra; corners with ten Mg(5,5)SrLaMg10 cuboctahedra; edges with two equivalent Sr(1)La2Mg10 cuboctahedra; edges with two equivalent Mg(6)LaMg11 cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Mg(3)Sr2La2Mg8 cuboctahedra; edges with two equivalent Mg(5)SrLaMg10 cuboctahedra; edges with two equivalent Mg(7)SrMg11 cuboctahedra; edges with two equivalent La(1)Sr2Mg10 cuboctahedra;  a faceface with one Sr(1)La2Mg10 cuboctahedra;  a faceface with one Mg(1)Mg12 cuboctahedra;  a faceface with one Mg(2)Mg12 cuboctahedra;  a faceface with one La(1)Sr2Mg10 cuboctahedra; faces with two equivalent Mg(6)LaMg11 cuboctahedra; faces with two equivalent Mg(7)SrMg11 cuboctahedra; faces with four equivalent Mg(4)Mg12 cuboctahedra; faces with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra; and faces with four equivalent Mg(5)SrLaMg10 cuboctahedra. There is one shorter (3.31 Å) and one longer (3.36 Å) Mg(5)-Mg(5) bond length. There is one shorter (3.30 Å) and one longer (3.41 Å) Mg(5)-Mg(6) bond length. There is one shorter (3.27 Å) and one longer (3.44 Å) Mg(5)-Mg(7) bond length. The Mg(5)-La(1) bond length is 3.41 Å. In the sixth Mg site, Mg(6) is bonded to one Mg(1); two equivalent Mg(3); two equivalent Mg(4); two equivalent Mg(7); four Mg(5,5); and one La(1) atom to form distorted MgLaMg11 cuboctahedra that share corners with four equivalent Mg(7)SrMg11 cuboctahedra; corners with six equivalent Mg(6)LaMg11 cuboctahedra; corners with eight Mg(5,5)SrLaMg10 cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mg(7)SrMg11 cuboctahedra; edges with two equivalent La(1)Sr2Mg10 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra; edges with four Mg(5,5)SrLaMg10 cuboctahedra;  a faceface with one Mg(1)Mg12 cuboctahedra;  a faceface with one La(1)Sr2Mg10 cuboctahedra; faces with two equivalent Mg(6)LaMg11 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(3)Sr2La2Mg8 cuboctahedra; faces with two equivalent Mg(7)SrMg11 cuboctahedra; faces with three equivalent Sr(1)La2Mg10 cuboctahedra; faces with three equivalent Mg(2)Mg12 cuboctahedra; and faces with four Mg(5,5)SrLaMg10 cuboctahedra. Both Mg(6)-Mg(7) bond lengths are 3.33 Å. The Mg(6)-Mg(5) bond length is 3.41 Å. The Mg(6)-La(1) bond length is 3.38 Å. In the seventh Mg site, Mg(7) is bonded to one Sr(1); one Mg(2); two equivalent Mg(3); two equivalent Mg(4); two equivalent Mg(6); and four Mg(5,5) atoms to form distorted MgSrMg11 cuboctahedra that share corners with four equivalent Mg(6)LaMg11 cuboctahedra; corners with six equivalent Mg(7)SrMg11 cuboctahedra; corners with eight Mg(5,5)SrLaMg10 cuboctahedra; edges with two equivalent Sr(1)La2Mg10 cuboctahedra; edges with two equivalent Mg(6)LaMg11 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra; edges with four Mg(5,5)SrLaMg10 cuboctahedra;  a faceface with one Sr(1)La2Mg10 cuboctahedra;  a faceface with one Mg(2)Mg12 cuboctahedra; faces with two equivalent Mg(6)LaMg11 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(3)Sr2La2Mg8 cuboctahedra; faces with two equivalent Mg(7)SrMg11 cuboctahedra; faces with three equivalent Mg(1)Mg12 cuboctahedra; faces with three equivalent La(1)Sr2Mg10 cuboctahedra; and faces with four Mg(5,5)SrLaMg10 cuboctahedra. The Mg(7)-Mg(5) bond length is 3.44 Å. In the eighth Mg site, Mg(5) is bonded to one Sr(1), one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), and one La(1) atom to form distorted MgSrLaMg10 cuboctahedra that share corners with four equivalent Mg(6)LaMg11 cuboctahedra; corners with four equivalent Mg(7)SrMg11 cuboctahedra; corners with ten Mg(5,5)SrLaMg10 cuboctahedra; edges with two equivalent Sr(1)La2Mg10 cuboctahedra; edges with two equivalent Mg(6)LaMg11 cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Mg(3)Sr2La2Mg8 cuboctahedra; edges with two equivalent Mg(5)SrLaMg10 cuboctahedra; edges with two equivalent Mg(7)SrMg11 cuboctahedra; edges with two equivalent La(1)Sr2Mg10 cuboctahedra;  a faceface with one Sr(1)La2Mg10 cuboctahedra;  a faceface with one Mg(1)Mg12 cuboctahedra;  a faceface with one Mg(2)Mg12 cuboctahedra;  a faceface with one La(1)Sr2Mg10 cuboctahedra; faces with two equivalent Mg(6)LaMg11 cuboctahedra; faces with two equivalent Mg(7)SrMg11 cuboctahedra; faces with four equivalent Mg(4)Mg12 cuboctahedra; faces with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra; and faces with four Mg(5,5)SrLaMg10 cuboctahedra. The Mg(5)-Sr(1) bond length is 3.43 Å. The Mg(5)-Mg(1) bond length is 3.17 Å. The Mg(5)-Mg(2) bond length is 3.18 Å. The Mg(5)-Mg(3) bond length is 3.40 Å. The Mg(5)-Mg(4) bond length is 3.15 Å. There is one shorter (3.31 Å) and one longer (3.36 Å) Mg(5)-Mg(5) bond length. The Mg(5)-La(1) bond length is 3.41 Å. La(1) is bonded to two equivalent Sr(1), two equivalent Mg(6), four equivalent Mg(3), and four equivalent Mg(5) atoms to form LaSr2Mg10 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra; corners with six equivalent La(1)Sr2Mg10 cuboctahedra; corners with eight equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Sr(1)La2Mg10 cuboctahedra; edges with four equivalent Mg(6)LaMg11 cuboctahedra; edges with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra; edges with eight Mg(5,5)SrLaMg10 cuboctahedra; faces with two equivalent Sr(1)La2Mg10 cuboctahedra; faces with two equivalent Mg(6)LaMg11 cuboctahedra; faces with two equivalent Mg(1)Mg12 cuboctahedra; faces with four equivalent Mg(3)Sr2La2Mg8 cuboctahedra; faces with four equivalent Mg(5)SrLaMg10 cuboctahedra; and faces with six equivalent Mg(7)SrMg11 cuboctahedra.