Mg14YAl crystallizes in the hexagonal P-6m2 space group. There are six 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 Al(1) atoms to form MgMg10Al2 cuboctahedra that share corners with four equivalent Y(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Mg10Al2 cuboctahedra; corners with eight Mg(2,2)Y2Mg10 cuboctahedra; edges with two equivalent Al(1)Mg12 cuboctahedra; edges with four equivalent Mg(1)Mg10Al2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight Mg(3,3)YMg10Al cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(2)Y2Mg10 cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; faces with four equivalent Mg(1)Mg10Al2 cuboctahedra; and faces with ten Mg(3,3)YMg10Al cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4); four Mg(2,2); four Mg(3,3); and two equivalent Y(1) atoms to form MgY2Mg10 cuboctahedra that share corners with four equivalent Al(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Y2Mg10 cuboctahedra; corners with eight equivalent Mg(1)Mg10Al2 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with four Mg(2,2)Y2Mg10 cuboctahedra; edges with eight Mg(3,3)YMg10Al cuboctahedra; faces with two equivalent Mg(1)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with four Mg(2,2)Y2Mg10 cuboctahedra; and faces with ten Mg(3,3)YMg10Al cuboctahedra. In the third Mg site, Mg(2) is bonded to two equivalent Mg(4), four equivalent Mg(2), four equivalent Mg(3), and two equivalent Y(1) atoms to form MgY2Mg10 cuboctahedra that share corners with four equivalent Al(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Y2Mg10 cuboctahedra; corners with eight equivalent Mg(1)Mg10Al2 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with four equivalent Mg(2)Y2Mg10 cuboctahedra; edges with eight equivalent Mg(3)YMg10Al cuboctahedra; faces with two equivalent Mg(1)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with four equivalent Mg(2)Y2Mg10 cuboctahedra; and faces with ten Mg(3,3)YMg10Al cuboctahedra. In the fourth Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), four equivalent Mg(3), one Y(1), and one Al(1) atom to form distorted MgYMg10Al cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen Mg(3,3)YMg10Al cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with two equivalent Al(1)Mg12 cuboctahedra; edges with four equivalent Mg(1)Mg10Al2 cuboctahedra; edges with four equivalent Mg(2)Y2Mg10 cuboctahedra; edges with four equivalent Mg(3)YMg10Al cuboctahedra;  a faceface with one Y(1)Mg12 cuboctahedra;  a faceface with one Al(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five equivalent Mg(1)Mg10Al2 cuboctahedra; faces with five Mg(2,2)Y2Mg10 cuboctahedra; and faces with six Mg(3,3)YMg10Al cuboctahedra. In the fifth Mg site, Mg(3) is bonded to two equivalent Mg(1); two Mg(2,2); two equivalent Mg(4); four Mg(3,3); one Y(1); and one Al(1) atom to form distorted MgYMg10Al cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen Mg(3,3)YMg10Al cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with two equivalent Al(1)Mg12 cuboctahedra; edges with four equivalent Mg(1)Mg10Al2 cuboctahedra; edges with four Mg(2,2)Y2Mg10 cuboctahedra; edges with four Mg(3,3)YMg10Al cuboctahedra;  a faceface with one Y(1)Mg12 cuboctahedra;  a faceface with one Al(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five equivalent Mg(1)Mg10Al2 cuboctahedra; faces with five Mg(2,2)Y2Mg10 cuboctahedra; and faces with six Mg(3,3)YMg10Al cuboctahedra. In the sixth Mg site, Mg(4) is bonded to three equivalent Mg(1); three Mg(2,2); and six Mg(3,3) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(4)Mg12 cuboctahedra; corners with twelve Mg(3,3)YMg10Al cuboctahedra; edges with six equivalent Mg(1)Mg10Al2 cuboctahedra; edges with six Mg(2,2)Y2Mg10 cuboctahedra; edges with six Mg(3,3)YMg10Al cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with three equivalent Mg(1)Mg10Al2 cuboctahedra; faces with three Mg(2,2)Y2Mg10 cuboctahedra; faces with three equivalent Y(1)Mg12 cuboctahedra; faces with three equivalent Al(1)Mg12 cuboctahedra; and faces with six Mg(3,3)YMg10Al cuboctahedra. Y(1) is bonded to six Mg(2,2) and six Mg(3,3) atoms to form YMg12 cuboctahedra that share corners with six equivalent Y(1)Mg12 cuboctahedra; corners with twelve equivalent Mg(1)Mg10Al2 cuboctahedra; edges with six Mg(2,2)Y2Mg10 cuboctahedra; edges with twelve Mg(3,3)YMg10Al cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; faces with six equivalent Mg(4)Mg12 cuboctahedra; faces with six Mg(2,2)Y2Mg10 cuboctahedra; and faces with six Mg(3,3)YMg10Al cuboctahedra. Al(1) is bonded to six equivalent Mg(1) and six Mg(3,3) atoms to form AlMg12 cuboctahedra that share corners with six equivalent Al(1)Mg12 cuboctahedra; corners with twelve Mg(2,2)Y2Mg10 cuboctahedra; edges with six equivalent Mg(1)Mg10Al2 cuboctahedra; edges with twelve Mg(3,3)YMg10Al cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with six equivalent Mg(1)Mg10Al2 cuboctahedra; faces with six equivalent Mg(4)Mg12 cuboctahedra; and faces with six Mg(3,3)YMg10Al cuboctahedra.
Mg14YAl crystallizes in the hexagonal P-6m2 space group. There are six 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 Al(1) atoms to form MgMg10Al2 cuboctahedra that share corners with four equivalent Y(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Mg10Al2 cuboctahedra; corners with eight Mg(2,2)Y2Mg10 cuboctahedra; edges with two equivalent Al(1)Mg12 cuboctahedra; edges with four equivalent Mg(1)Mg10Al2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight Mg(3,3)YMg10Al cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(2)Y2Mg10 cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; faces with four equivalent Mg(1)Mg10Al2 cuboctahedra; and faces with ten Mg(3,3)YMg10Al cuboctahedra. Both Mg(1)-Mg(4) bond lengths are 3.23 Å. There are two shorter (3.19 Å) and two longer (3.24 Å) Mg(1)-Mg(1) bond lengths. All Mg(1)-Mg(3,3) bond lengths are 3.14 Å. Both Mg(1)-Al(1) bond lengths are 3.22 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4); four Mg(2,2); four Mg(3,3); and two equivalent Y(1) atoms to form MgY2Mg10 cuboctahedra that share corners with four equivalent Al(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Y2Mg10 cuboctahedra; corners with eight equivalent Mg(1)Mg10Al2 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with four Mg(2,2)Y2Mg10 cuboctahedra; edges with eight Mg(3,3)YMg10Al cuboctahedra; faces with two equivalent Mg(1)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with four Mg(2,2)Y2Mg10 cuboctahedra; and faces with ten Mg(3,3)YMg10Al cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.16 Å. There are two shorter (3.13 Å) and two longer (3.30 Å) Mg(2)-Mg(2,2) bond lengths. All Mg(2)-Mg(3,3) bond lengths are 3.23 Å. Both Mg(2)-Y(1) bond lengths are 3.22 Å. In the third Mg site, Mg(2) is bonded to two equivalent Mg(4), four equivalent Mg(2), four equivalent Mg(3), and two equivalent Y(1) atoms to form MgY2Mg10 cuboctahedra that share corners with four equivalent Al(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Y2Mg10 cuboctahedra; corners with eight equivalent Mg(1)Mg10Al2 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with four equivalent Mg(2)Y2Mg10 cuboctahedra; edges with eight equivalent Mg(3)YMg10Al cuboctahedra; faces with two equivalent Mg(1)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with four equivalent Mg(2)Y2Mg10 cuboctahedra; and faces with ten Mg(3,3)YMg10Al cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.16 Å. All Mg(2)-Mg(3) bond lengths are 3.23 Å. Both Mg(2)-Y(1) bond lengths are 3.22 Å. In the fourth Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), four equivalent Mg(3), one Y(1), and one Al(1) atom to form distorted MgYMg10Al cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen Mg(3,3)YMg10Al cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with two equivalent Al(1)Mg12 cuboctahedra; edges with four equivalent Mg(1)Mg10Al2 cuboctahedra; edges with four equivalent Mg(2)Y2Mg10 cuboctahedra; edges with four equivalent Mg(3)YMg10Al cuboctahedra;  a faceface with one Y(1)Mg12 cuboctahedra;  a faceface with one Al(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five equivalent Mg(1)Mg10Al2 cuboctahedra; faces with five Mg(2,2)Y2Mg10 cuboctahedra; and faces with six Mg(3,3)YMg10Al cuboctahedra. Both Mg(3)-Mg(4) bond lengths are 3.22 Å. There are two shorter (3.19 Å) and two longer (3.24 Å) Mg(3)-Mg(3) bond lengths. The Mg(3)-Y(1) bond length is 3.23 Å. The Mg(3)-Al(1) bond length is 3.12 Å. In the fifth Mg site, Mg(3) is bonded to two equivalent Mg(1); two Mg(2,2); two equivalent Mg(4); four Mg(3,3); one Y(1); and one Al(1) atom to form distorted MgYMg10Al cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen Mg(3,3)YMg10Al cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with two equivalent Al(1)Mg12 cuboctahedra; edges with four equivalent Mg(1)Mg10Al2 cuboctahedra; edges with four Mg(2,2)Y2Mg10 cuboctahedra; edges with four Mg(3,3)YMg10Al cuboctahedra;  a faceface with one Y(1)Mg12 cuboctahedra;  a faceface with one Al(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five equivalent Mg(1)Mg10Al2 cuboctahedra; faces with five Mg(2,2)Y2Mg10 cuboctahedra; and faces with six Mg(3,3)YMg10Al cuboctahedra. Both Mg(3)-Mg(4) bond lengths are 3.22 Å. There is one shorter (3.19 Å) and one longer (3.24 Å) Mg(3)-Mg(3) bond length. The Mg(3)-Y(1) bond length is 3.23 Å. The Mg(3)-Al(1) bond length is 3.12 Å. In the sixth Mg site, Mg(4) is bonded to three equivalent Mg(1); three Mg(2,2); and six Mg(3,3) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(4)Mg12 cuboctahedra; corners with twelve Mg(3,3)YMg10Al cuboctahedra; edges with six equivalent Mg(1)Mg10Al2 cuboctahedra; edges with six Mg(2,2)Y2Mg10 cuboctahedra; edges with six Mg(3,3)YMg10Al cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with three equivalent Mg(1)Mg10Al2 cuboctahedra; faces with three Mg(2,2)Y2Mg10 cuboctahedra; faces with three equivalent Y(1)Mg12 cuboctahedra; faces with three equivalent Al(1)Mg12 cuboctahedra; and faces with six Mg(3,3)YMg10Al cuboctahedra. Y(1) is bonded to six Mg(2,2) and six Mg(3,3) atoms to form YMg12 cuboctahedra that share corners with six equivalent Y(1)Mg12 cuboctahedra; corners with twelve equivalent Mg(1)Mg10Al2 cuboctahedra; edges with six Mg(2,2)Y2Mg10 cuboctahedra; edges with twelve Mg(3,3)YMg10Al cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; faces with six equivalent Mg(4)Mg12 cuboctahedra; faces with six Mg(2,2)Y2Mg10 cuboctahedra; and faces with six Mg(3,3)YMg10Al cuboctahedra. Al(1) is bonded to six equivalent Mg(1) and six Mg(3,3) atoms to form AlMg12 cuboctahedra that share corners with six equivalent Al(1)Mg12 cuboctahedra; corners with twelve Mg(2,2)Y2Mg10 cuboctahedra; edges with six equivalent Mg(1)Mg10Al2 cuboctahedra; edges with twelve Mg(3,3)YMg10Al cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with six equivalent Mg(1)Mg10Al2 cuboctahedra; faces with six equivalent Mg(4)Mg12 cuboctahedra; and faces with six Mg(3,3)YMg10Al cuboctahedra.