SrMg14Y crystallizes in the hexagonal P-6m2 space group. Sr(1) is bonded to six Mg(2,2) and six Mg(3,3,3) atoms to form SrMg12 cuboctahedra that share corners with six equivalent Sr(1)Mg12 cuboctahedra; corners with twelve equivalent Mg(1)Y2Mg10 cuboctahedra; edges with six Mg(2,2)Sr2Mg10 cuboctahedra; edges with twelve Mg(3,3,3)SrYMg10 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with six equivalent Mg(4)Mg12 cuboctahedra; faces with six Mg(2,2)Sr2Mg10 cuboctahedra; and faces with six Mg(3,3,3)SrYMg10 cuboctahedra. There are seven inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(4); four equivalent Mg(1); four Mg(3,3); and two equivalent Y(1) atoms to form MgY2Mg10 cuboctahedra that share corners with four equivalent Sr(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Y2Mg10 cuboctahedra; corners with eight Mg(2,2)Sr2Mg10 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with four equivalent Mg(1)Y2Mg10 cuboctahedra; edges with eight Mg(3,3)SrYMg10 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(2)Sr2Mg10 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with four equivalent Mg(1)Y2Mg10 cuboctahedra; and faces with ten Mg(3,3,3)SrYMg10 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Sr(1); two equivalent Mg(4); four Mg(2,2); and four Mg(3,3) atoms to form distorted MgSr2Mg10 cuboctahedra that share corners with four equivalent Y(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Sr2Mg10 cuboctahedra; corners with eight equivalent Mg(1)Y2Mg10 cuboctahedra; edges with two equivalent Sr(1)Mg12 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with four Mg(2,2)Sr2Mg10 cuboctahedra; edges with eight Mg(3,3)SrYMg10 cuboctahedra; faces with two equivalent Sr(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(1)Y2Mg10 cuboctahedra; faces with four Mg(2,2)Sr2Mg10 cuboctahedra; and faces with ten Mg(3,3,3)SrYMg10 cuboctahedra. In the third Mg site, Mg(2) is bonded to two equivalent Sr(1); two equivalent Mg(4); four equivalent Mg(2); and four Mg(3,3) atoms to form distorted MgSr2Mg10 cuboctahedra that share corners with four equivalent Y(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Sr2Mg10 cuboctahedra; corners with eight equivalent Mg(1)Y2Mg10 cuboctahedra; edges with two equivalent Sr(1)Mg12 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with four equivalent Mg(2)Sr2Mg10 cuboctahedra; edges with eight Mg(3,3)SrYMg10 cuboctahedra; faces with two equivalent Sr(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(1)Y2Mg10 cuboctahedra; faces with four equivalent Mg(2)Sr2Mg10 cuboctahedra; and faces with ten Mg(3,3,3)SrYMg10 cuboctahedra. In the fourth Mg site, Mg(3) is bonded to one Sr(1); two equivalent Mg(1); two Mg(2,2); two equivalent Mg(4); four Mg(3,3); and one Y(1) atom to form distorted MgSrYMg10 cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen Mg(3,3,3)SrYMg10 cuboctahedra; edges with two equivalent Sr(1)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four Mg(2,2)Sr2Mg10 cuboctahedra; edges with four Mg(3,3)SrYMg10 cuboctahedra; edges with four equivalent Mg(1)Y2Mg10 cuboctahedra;  a faceface with one Sr(1)Mg12 cuboctahedra;  a faceface with one Y(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five Mg(2,2)Sr2Mg10 cuboctahedra; faces with five equivalent Mg(1)Y2Mg10 cuboctahedra; and faces with six Mg(3,3,3)SrYMg10 cuboctahedra. In the fifth Mg site, Mg(3) is bonded to one Sr(1); two equivalent Mg(1); two equivalent Mg(2); two equivalent Mg(4); four Mg(3,3); and one Y(1) atom to form distorted MgSrYMg10 cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen Mg(3,3,3)SrYMg10 cuboctahedra; edges with two equivalent Sr(1)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four equivalent Mg(2)Sr2Mg10 cuboctahedra; edges with four Mg(3,3)SrYMg10 cuboctahedra; edges with four equivalent Mg(1)Y2Mg10 cuboctahedra;  a faceface with one Sr(1)Mg12 cuboctahedra;  a faceface with one Y(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five Mg(2,2)Sr2Mg10 cuboctahedra; faces with five equivalent Mg(1)Y2Mg10 cuboctahedra; and faces with six Mg(3,3,3)SrYMg10 cuboctahedra. In the sixth Mg site, Mg(3) is bonded to one Sr(1); two equivalent Mg(1); two Mg(2,2); two equivalent Mg(4); four Mg(3,3); and one Y(1) atom to form distorted MgSrYMg10 cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen Mg(3,3,3)SrYMg10 cuboctahedra; edges with two equivalent Sr(1)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four Mg(2,2)Sr2Mg10 cuboctahedra; edges with four Mg(3,3)SrYMg10 cuboctahedra; edges with four equivalent Mg(1)Y2Mg10 cuboctahedra;  a faceface with one Sr(1)Mg12 cuboctahedra;  a faceface with one Y(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five Mg(2,2)Sr2Mg10 cuboctahedra; faces with five equivalent Mg(1)Y2Mg10 cuboctahedra; and faces with six Mg(3,3,3)SrYMg10 cuboctahedra. In the seventh Mg site, Mg(4) is bonded to three equivalent Mg(1); three Mg(2,2); and six Mg(3,3,3) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(4)Mg12 cuboctahedra; corners with twelve Mg(3,3,3)SrYMg10 cuboctahedra; edges with six Mg(2,2)Sr2Mg10 cuboctahedra; edges with six Mg(3,3,3)SrYMg10 cuboctahedra; edges with six equivalent Mg(1)Y2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with three equivalent Sr(1)Mg12 cuboctahedra; faces with three Mg(2,2)Sr2Mg10 cuboctahedra; faces with three equivalent Mg(1)Y2Mg10 cuboctahedra; faces with three equivalent Y(1)Mg12 cuboctahedra; and faces with six Mg(3,3,3)SrYMg10 cuboctahedra. Y(1) is bonded to six equivalent Mg(1) and six Mg(3,3,3) atoms to form YMg12 cuboctahedra that share corners with six equivalent Y(1)Mg12 cuboctahedra; corners with twelve Mg(2,2)Sr2Mg10 cuboctahedra; edges with six equivalent Mg(1)Y2Mg10 cuboctahedra; edges with twelve Mg(3,3,3)SrYMg10 cuboctahedra; faces with two equivalent Sr(1)Mg12 cuboctahedra; faces with six equivalent Mg(4)Mg12 cuboctahedra; faces with six Mg(3,3,3)SrYMg10 cuboctahedra; and faces with six equivalent Mg(1)Y2Mg10 cuboctahedra.
SrMg14Y crystallizes in the hexagonal P-6m2 space group. Sr(1) is bonded to six Mg(2,2) and six Mg(3,3,3) atoms to form SrMg12 cuboctahedra that share corners with six equivalent Sr(1)Mg12 cuboctahedra; corners with twelve equivalent Mg(1)Y2Mg10 cuboctahedra; edges with six Mg(2,2)Sr2Mg10 cuboctahedra; edges with twelve Mg(3,3,3)SrYMg10 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with six equivalent Mg(4)Mg12 cuboctahedra; faces with six Mg(2,2)Sr2Mg10 cuboctahedra; and faces with six Mg(3,3,3)SrYMg10 cuboctahedra. All Sr(1)-Mg(2,2) bond lengths are 3.35 Å. All Sr(1)-Mg(3,3,3) bond lengths are 3.35 Å. There are seven inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(4); four equivalent Mg(1); four Mg(3,3); and two equivalent Y(1) atoms to form MgY2Mg10 cuboctahedra that share corners with four equivalent Sr(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Y2Mg10 cuboctahedra; corners with eight Mg(2,2)Sr2Mg10 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with four equivalent Mg(1)Y2Mg10 cuboctahedra; edges with eight Mg(3,3)SrYMg10 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(2)Sr2Mg10 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with four equivalent Mg(1)Y2Mg10 cuboctahedra; and faces with ten Mg(3,3,3)SrYMg10 cuboctahedra. Both Mg(1)-Mg(4) bond lengths are 3.30 Å. There are two shorter (3.29 Å) and two longer (3.41 Å) Mg(1)-Mg(1) bond lengths. All Mg(1)-Mg(3,3) bond lengths are 3.20 Å. Both Mg(1)-Y(1) bond lengths are 3.35 Å. In the second Mg site, Mg(2) is bonded to two equivalent Sr(1); two equivalent Mg(4); four Mg(2,2); and four Mg(3,3) atoms to form distorted MgSr2Mg10 cuboctahedra that share corners with four equivalent Y(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Sr2Mg10 cuboctahedra; corners with eight equivalent Mg(1)Y2Mg10 cuboctahedra; edges with two equivalent Sr(1)Mg12 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with four Mg(2,2)Sr2Mg10 cuboctahedra; edges with eight Mg(3,3)SrYMg10 cuboctahedra; faces with two equivalent Sr(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(1)Y2Mg10 cuboctahedra; faces with four Mg(2,2)Sr2Mg10 cuboctahedra; and faces with ten Mg(3,3,3)SrYMg10 cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.29 Å. There are two shorter (3.26 Å) and two longer (3.43 Å) Mg(2)-Mg(2,2) bond lengths. All Mg(2)-Mg(3,3) bond lengths are 3.28 Å. In the third Mg site, Mg(2) is bonded to two equivalent Sr(1); two equivalent Mg(4); four equivalent Mg(2); and four Mg(3,3) atoms to form distorted MgSr2Mg10 cuboctahedra that share corners with four equivalent Y(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Sr2Mg10 cuboctahedra; corners with eight equivalent Mg(1)Y2Mg10 cuboctahedra; edges with two equivalent Sr(1)Mg12 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with four equivalent Mg(2)Sr2Mg10 cuboctahedra; edges with eight Mg(3,3)SrYMg10 cuboctahedra; faces with two equivalent Sr(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(1)Y2Mg10 cuboctahedra; faces with four equivalent Mg(2)Sr2Mg10 cuboctahedra; and faces with ten Mg(3,3,3)SrYMg10 cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.29 Å. All Mg(2)-Mg(3,3) bond lengths are 3.28 Å. In the fourth Mg site, Mg(3) is bonded to one Sr(1); two equivalent Mg(1); two Mg(2,2); two equivalent Mg(4); four Mg(3,3); and one Y(1) atom to form distorted MgSrYMg10 cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen Mg(3,3,3)SrYMg10 cuboctahedra; edges with two equivalent Sr(1)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four Mg(2,2)Sr2Mg10 cuboctahedra; edges with four Mg(3,3)SrYMg10 cuboctahedra; edges with four equivalent Mg(1)Y2Mg10 cuboctahedra;  a faceface with one Sr(1)Mg12 cuboctahedra;  a faceface with one Y(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five Mg(2,2)Sr2Mg10 cuboctahedra; faces with five equivalent Mg(1)Y2Mg10 cuboctahedra; and faces with six Mg(3,3,3)SrYMg10 cuboctahedra. Both Mg(3)-Mg(4) bond lengths are 3.35 Å. There are two shorter (3.23 Å) and two longer (3.47 Å) Mg(3)-Mg(3,3) bond lengths. The Mg(3)-Y(1) bond length is 3.27 Å. In the fifth Mg site, Mg(3) is bonded to one Sr(1); two equivalent Mg(1); two equivalent Mg(2); two equivalent Mg(4); four Mg(3,3); and one Y(1) atom to form distorted MgSrYMg10 cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen Mg(3,3,3)SrYMg10 cuboctahedra; edges with two equivalent Sr(1)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four equivalent Mg(2)Sr2Mg10 cuboctahedra; edges with four Mg(3,3)SrYMg10 cuboctahedra; edges with four equivalent Mg(1)Y2Mg10 cuboctahedra;  a faceface with one Sr(1)Mg12 cuboctahedra;  a faceface with one Y(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five Mg(2,2)Sr2Mg10 cuboctahedra; faces with five equivalent Mg(1)Y2Mg10 cuboctahedra; and faces with six Mg(3,3,3)SrYMg10 cuboctahedra. Both Mg(3)-Mg(4) bond lengths are 3.35 Å. There is one shorter (3.23 Å) and one longer (3.47 Å) Mg(3)-Mg(3) bond length. The Mg(3)-Y(1) bond length is 3.27 Å. In the sixth Mg site, Mg(3) is bonded to one Sr(1); two equivalent Mg(1); two Mg(2,2); two equivalent Mg(4); four Mg(3,3); and one Y(1) atom to form distorted MgSrYMg10 cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen Mg(3,3,3)SrYMg10 cuboctahedra; edges with two equivalent Sr(1)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four Mg(2,2)Sr2Mg10 cuboctahedra; edges with four Mg(3,3)SrYMg10 cuboctahedra; edges with four equivalent Mg(1)Y2Mg10 cuboctahedra;  a faceface with one Sr(1)Mg12 cuboctahedra;  a faceface with one Y(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five Mg(2,2)Sr2Mg10 cuboctahedra; faces with five equivalent Mg(1)Y2Mg10 cuboctahedra; and faces with six Mg(3,3,3)SrYMg10 cuboctahedra. Both Mg(3)-Mg(1) bond lengths are 3.20 Å. The Mg(3)-Mg(2) bond length is 3.28 Å. Both Mg(3)-Mg(4) bond lengths are 3.35 Å. The Mg(3)-Y(1) bond length is 3.27 Å. In the seventh Mg site, Mg(4) is bonded to three equivalent Mg(1); three Mg(2,2); and six Mg(3,3,3) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(4)Mg12 cuboctahedra; corners with twelve Mg(3,3,3)SrYMg10 cuboctahedra; edges with six Mg(2,2)Sr2Mg10 cuboctahedra; edges with six Mg(3,3,3)SrYMg10 cuboctahedra; edges with six equivalent Mg(1)Y2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with three equivalent Sr(1)Mg12 cuboctahedra; faces with three Mg(2,2)Sr2Mg10 cuboctahedra; faces with three equivalent Mg(1)Y2Mg10 cuboctahedra; faces with three equivalent Y(1)Mg12 cuboctahedra; and faces with six Mg(3,3,3)SrYMg10 cuboctahedra. Y(1) is bonded to six equivalent Mg(1) and six Mg(3,3,3) atoms to form YMg12 cuboctahedra that share corners with six equivalent Y(1)Mg12 cuboctahedra; corners with twelve Mg(2,2)Sr2Mg10 cuboctahedra; edges with six equivalent Mg(1)Y2Mg10 cuboctahedra; edges with twelve Mg(3,3,3)SrYMg10 cuboctahedra; faces with two equivalent Sr(1)Mg12 cuboctahedra; faces with six equivalent Mg(4)Mg12 cuboctahedra; faces with six Mg(3,3,3)SrYMg10 cuboctahedra; and faces with six equivalent Mg(1)Y2Mg10 cuboctahedra.