Mg14CoAl crystallizes in the hexagonal P-6m2 space group. There are seven inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(4); four Mg(1,1); four Mg(3,3); and two equivalent Al(1) atoms to form MgMg10Al2 cuboctahedra that share corners with four equivalent Co(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Mg10Al2 cuboctahedra; corners with eight equivalent Mg(2)Mg10Co2 cuboctahedra; edges with two equivalent Al(1)Mg12 cuboctahedra; edges with four Mg(1,1)Mg10Al2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(2)Mg10Co2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; and faces with four Mg(1,1)Mg10Al2 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4); four equivalent Mg(2); four Mg(3,3); and two equivalent Co(1) atoms to form distorted MgMg10Co2 cuboctahedra that share corners with four equivalent Al(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Mg10Co2 cuboctahedra; corners with eight Mg(1,1)Mg10Al2 cuboctahedra; edges with two equivalent Co(1)Mg12 cuboctahedra; edges with four equivalent Mg(2)Mg10Co2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(1)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Co(1)Mg12 cuboctahedra; and faces with four equivalent Mg(2)Mg10Co2 cuboctahedra. In the third Mg site, Mg(1) is bonded to two equivalent Mg(4); four Mg(1,1); four Mg(3,3); and two equivalent Al(1) atoms to form MgMg10Al2 cuboctahedra that share corners with four equivalent Co(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Mg10Al2 cuboctahedra; corners with eight equivalent Mg(2)Mg10Co2 cuboctahedra; edges with two equivalent Al(1)Mg12 cuboctahedra; edges with four Mg(1,1)Mg10Al2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(2)Mg10Co2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; and faces with four Mg(1,1)Mg10Al2 cuboctahedra. In the fourth Mg site, Mg(1) is bonded to two equivalent Mg(4); four Mg(1,1); four equivalent Mg(3); and two equivalent Al(1) atoms to form MgMg10Al2 cuboctahedra that share corners with four equivalent Co(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Mg10Al2 cuboctahedra; corners with eight equivalent Mg(2)Mg10Co2 cuboctahedra; edges with two equivalent Al(1)Mg12 cuboctahedra; edges with four Mg(1,1)Mg10Al2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(2)Mg10Co2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; and faces with four Mg(1,1)Mg10Al2 cuboctahedra. In the fifth Mg site, Mg(3) is bonded in a 12-coordinate geometry to two Mg(1,1); two equivalent Mg(2); two equivalent Mg(4); four equivalent Mg(3); one Co(1); and one Al(1) atom. In the sixth Mg site, Mg(3) is bonded in a 12-coordinate geometry to two Mg(1,1); two equivalent Mg(2); two equivalent Mg(4); four Mg(3,3); one Co(1); and one Al(1) atom. In the seventh Mg site, Mg(4) is bonded to three Mg(1,1,1); three equivalent Mg(2); and six Mg(3,3) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(4)Mg12 cuboctahedra; edges with six Mg(1,1,1)Mg10Al2 cuboctahedra; edges with six equivalent Mg(2)Mg10Co2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with three Mg(1,1,1)Mg10Al2 cuboctahedra; faces with three equivalent Mg(2)Mg10Co2 cuboctahedra; faces with three equivalent Co(1)Mg12 cuboctahedra; and faces with three equivalent Al(1)Mg12 cuboctahedra. Co(1) is bonded to six equivalent Mg(2) and six Mg(3,3) atoms to form CoMg12 cuboctahedra that share corners with six equivalent Co(1)Mg12 cuboctahedra; corners with twelve Mg(1,1,1)Mg10Al2 cuboctahedra; edges with six equivalent Mg(2)Mg10Co2 cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; faces with six equivalent Mg(2)Mg10Co2 cuboctahedra; and faces with six equivalent Mg(4)Mg12 cuboctahedra. Al(1) is bonded to six Mg(1,1,1) and six Mg(3,3) atoms to form AlMg12 cuboctahedra that share corners with six equivalent Al(1)Mg12 cuboctahedra; corners with twelve equivalent Mg(2)Mg10Co2 cuboctahedra; edges with six Mg(1,1,1)Mg10Al2 cuboctahedra; faces with two equivalent Co(1)Mg12 cuboctahedra; faces with six Mg(1,1,1)Mg10Al2 cuboctahedra; and faces with six equivalent Mg(4)Mg12 cuboctahedra.
Mg14CoAl crystallizes in the hexagonal P-6m2 space group. There are seven inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(4); four Mg(1,1); four Mg(3,3); and two equivalent Al(1) atoms to form MgMg10Al2 cuboctahedra that share corners with four equivalent Co(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Mg10Al2 cuboctahedra; corners with eight equivalent Mg(2)Mg10Co2 cuboctahedra; edges with two equivalent Al(1)Mg12 cuboctahedra; edges with four Mg(1,1)Mg10Al2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(2)Mg10Co2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; and faces with four Mg(1,1)Mg10Al2 cuboctahedra. Both Mg(1)-Mg(4) bond lengths are 3.04 Å. There are two shorter (3.12 Å) and two longer (3.15 Å) Mg(1)-Mg(1,1) bond lengths. All Mg(1)-Mg(3,3) bond lengths are 3.16 Å. Both Mg(1)-Al(1) bond lengths are 3.13 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4); four equivalent Mg(2); four Mg(3,3); and two equivalent Co(1) atoms to form distorted MgMg10Co2 cuboctahedra that share corners with four equivalent Al(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Mg10Co2 cuboctahedra; corners with eight Mg(1,1)Mg10Al2 cuboctahedra; edges with two equivalent Co(1)Mg12 cuboctahedra; edges with four equivalent Mg(2)Mg10Co2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(1)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Co(1)Mg12 cuboctahedra; and faces with four equivalent Mg(2)Mg10Co2 cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.06 Å. There are two shorter (3.10 Å) and two longer (3.17 Å) Mg(2)-Mg(2) bond lengths. All Mg(2)-Mg(3,3) bond lengths are 3.01 Å. Both Mg(2)-Co(1) bond lengths are 3.13 Å. In the third Mg site, Mg(1) is bonded to two equivalent Mg(4); four Mg(1,1); four Mg(3,3); and two equivalent Al(1) atoms to form MgMg10Al2 cuboctahedra that share corners with four equivalent Co(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Mg10Al2 cuboctahedra; corners with eight equivalent Mg(2)Mg10Co2 cuboctahedra; edges with two equivalent Al(1)Mg12 cuboctahedra; edges with four Mg(1,1)Mg10Al2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(2)Mg10Co2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; and faces with four Mg(1,1)Mg10Al2 cuboctahedra. Both Mg(1)-Mg(4) bond lengths are 3.04 Å. There is one shorter (3.12 Å) and one longer (3.15 Å) Mg(1)-Mg(1) bond length. All Mg(1)-Mg(3,3) bond lengths are 3.16 Å. Both Mg(1)-Al(1) bond lengths are 3.13 Å. In the fourth Mg site, Mg(1) is bonded to two equivalent Mg(4); four Mg(1,1); four equivalent Mg(3); and two equivalent Al(1) atoms to form MgMg10Al2 cuboctahedra that share corners with four equivalent Co(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Mg10Al2 cuboctahedra; corners with eight equivalent Mg(2)Mg10Co2 cuboctahedra; edges with two equivalent Al(1)Mg12 cuboctahedra; edges with four Mg(1,1)Mg10Al2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(2)Mg10Co2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; and faces with four Mg(1,1)Mg10Al2 cuboctahedra. Both Mg(1)-Mg(4) bond lengths are 3.04 Å. All Mg(1)-Mg(3) bond lengths are 3.16 Å. Both Mg(1)-Al(1) bond lengths are 3.13 Å. In the fifth Mg site, Mg(3) is bonded in a 12-coordinate geometry to two Mg(1,1); two equivalent Mg(2); two equivalent Mg(4); four equivalent Mg(3); one Co(1); and one Al(1) atom. Both Mg(3)-Mg(4) bond lengths are 3.14 Å. There are two shorter (2.98 Å) and two longer (3.29 Å) Mg(3)-Mg(3) bond lengths. The Mg(3)-Co(1) bond length is 2.92 Å. The Mg(3)-Al(1) bond length is 3.09 Å. In the sixth Mg site, Mg(3) is bonded in a 12-coordinate geometry to two Mg(1,1); two equivalent Mg(2); two equivalent Mg(4); four Mg(3,3); one Co(1); and one Al(1) atom. Both Mg(3)-Mg(4) bond lengths are 3.14 Å. There is one shorter (2.98 Å) and one longer (3.29 Å) Mg(3)-Mg(3) bond length. The Mg(3)-Co(1) bond length is 2.92 Å. The Mg(3)-Al(1) bond length is 3.09 Å. In the seventh Mg site, Mg(4) is bonded to three Mg(1,1,1); three equivalent Mg(2); and six Mg(3,3) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(4)Mg12 cuboctahedra; edges with six Mg(1,1,1)Mg10Al2 cuboctahedra; edges with six equivalent Mg(2)Mg10Co2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with three Mg(1,1,1)Mg10Al2 cuboctahedra; faces with three equivalent Mg(2)Mg10Co2 cuboctahedra; faces with three equivalent Co(1)Mg12 cuboctahedra; and faces with three equivalent Al(1)Mg12 cuboctahedra. Co(1) is bonded to six equivalent Mg(2) and six Mg(3,3) atoms to form CoMg12 cuboctahedra that share corners with six equivalent Co(1)Mg12 cuboctahedra; corners with twelve Mg(1,1,1)Mg10Al2 cuboctahedra; edges with six equivalent Mg(2)Mg10Co2 cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; faces with six equivalent Mg(2)Mg10Co2 cuboctahedra; and faces with six equivalent Mg(4)Mg12 cuboctahedra. Al(1) is bonded to six Mg(1,1,1) and six Mg(3,3) atoms to form AlMg12 cuboctahedra that share corners with six equivalent Al(1)Mg12 cuboctahedra; corners with twelve equivalent Mg(2)Mg10Co2 cuboctahedra; edges with six Mg(1,1,1)Mg10Al2 cuboctahedra; faces with two equivalent Co(1)Mg12 cuboctahedra; faces with six Mg(1,1,1)Mg10Al2 cuboctahedra; and faces with six equivalent Mg(4)Mg12 cuboctahedra.