Mg14CrAl 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 equivalent Mg(3); and two equivalent Al(1) atoms to form MgMg10Al2 cuboctahedra that share corners with four equivalent Cr(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Mg10Al2 cuboctahedra; corners with eight Mg(2,2)Mg10Cr2 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; edges with eight equivalent Mg(3)Mg10AlCr cuboctahedra; faces with two equivalent Mg(2)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; faces with four Mg(1,1)Mg10Al2 cuboctahedra; and faces with ten equivalent Mg(3)Mg10AlCr cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4); four Mg(2,2); four equivalent Mg(3); and two equivalent Cr(1) atoms to form MgMg10Cr2 cuboctahedra that share corners with four equivalent Al(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Mg10Cr2 cuboctahedra; corners with eight Mg(1,1)Mg10Al2 cuboctahedra; edges with two equivalent Cr(1)Mg12 cuboctahedra; edges with four Mg(2,2)Mg10Cr2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight equivalent Mg(3)Mg10AlCr cuboctahedra; faces with two equivalent Mg(1)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Cr(1)Mg12 cuboctahedra; faces with four Mg(2,2)Mg10Cr2 cuboctahedra; and faces with ten equivalent Mg(3)Mg10AlCr cuboctahedra. In the third Mg site, Mg(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Al(1) atoms to form MgMg10Al2 cuboctahedra that share corners with four equivalent Cr(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Mg10Al2 cuboctahedra; corners with eight Mg(2,2)Mg10Cr2 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 equivalent Mg(3)Mg10AlCr cuboctahedra; faces with two equivalent Mg(2)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; faces with four equivalent Mg(1)Mg10Al2 cuboctahedra; and faces with ten equivalent Mg(3)Mg10AlCr cuboctahedra. In the fourth Mg site, Mg(2) is bonded to two equivalent Mg(4); four Mg(2,2); four equivalent Mg(3); and two equivalent Cr(1) atoms to form MgMg10Cr2 cuboctahedra that share corners with four equivalent Al(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Mg10Cr2 cuboctahedra; corners with eight equivalent Mg(1)Mg10Al2 cuboctahedra; edges with two equivalent Cr(1)Mg12 cuboctahedra; edges with four Mg(2,2)Mg10Cr2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight equivalent Mg(3)Mg10AlCr cuboctahedra; faces with two equivalent Mg(1)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Cr(1)Mg12 cuboctahedra; faces with four Mg(2,2)Mg10Cr2 cuboctahedra; and faces with ten equivalent Mg(3)Mg10AlCr cuboctahedra. In the fifth Mg site, Mg(2) is bonded to two equivalent Mg(4); four Mg(2,2); four equivalent Mg(3); and two equivalent Cr(1) atoms to form MgMg10Cr2 cuboctahedra that share corners with four equivalent Al(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Mg10Cr2 cuboctahedra; corners with eight Mg(1,1)Mg10Al2 cuboctahedra; edges with two equivalent Cr(1)Mg12 cuboctahedra; edges with four Mg(2,2)Mg10Cr2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight equivalent Mg(3)Mg10AlCr cuboctahedra; faces with two equivalent Mg(1)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Cr(1)Mg12 cuboctahedra; faces with four Mg(2,2)Mg10Cr2 cuboctahedra; and faces with ten equivalent Mg(3)Mg10AlCr cuboctahedra. In the sixth Mg site, Mg(3) is bonded to two Mg(1,1); two Mg(2,2); two equivalent Mg(4); four equivalent Mg(3); one Cr(1); and one Al(1) atom to form distorted MgMg10AlCr cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen equivalent Mg(3)Mg10AlCr cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Cr(1)Mg12 cuboctahedra; edges with two equivalent Al(1)Mg12 cuboctahedra; edges with four Mg(1,1)Mg10Al2 cuboctahedra; edges with four equivalent Mg(3)Mg10AlCr cuboctahedra; edges with four Mg(2,2)Mg10Cr2 cuboctahedra;  a faceface with one Cr(1)Mg12 cuboctahedra;  a faceface with one Al(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five Mg(1,1)Mg10Al2 cuboctahedra; faces with five Mg(2,2,2)Mg10Cr2 cuboctahedra; and faces with six equivalent Mg(3)Mg10AlCr cuboctahedra. In the seventh Mg site, Mg(4) is bonded to three Mg(1,1); three Mg(2,2,2); and six equivalent Mg(3) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(4)Mg12 cuboctahedra; corners with twelve equivalent Mg(3)Mg10AlCr cuboctahedra; edges with six Mg(1,1)Mg10Al2 cuboctahedra; edges with six equivalent Mg(3)Mg10AlCr cuboctahedra; edges with six Mg(2,2,2)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with three Mg(1,1)Mg10Al2 cuboctahedra; faces with three Mg(2,2,2)Mg10Cr2 cuboctahedra; faces with three equivalent Cr(1)Mg12 cuboctahedra; faces with three equivalent Al(1)Mg12 cuboctahedra; and faces with six equivalent Mg(3)Mg10AlCr cuboctahedra. Cr(1) is bonded to six Mg(2,2,2) and six equivalent Mg(3) atoms to form CrMg12 cuboctahedra that share corners with six equivalent Cr(1)Mg12 cuboctahedra; corners with twelve Mg(1,1)Mg10Al2 cuboctahedra; edges with six Mg(2,2,2)Mg10Cr2 cuboctahedra; edges with twelve equivalent Mg(3)Mg10AlCr cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; faces with six equivalent Mg(3)Mg10AlCr cuboctahedra; faces with six Mg(2,2,2)Mg10Cr2 cuboctahedra; and faces with six equivalent Mg(4)Mg12 cuboctahedra. Al(1) is bonded to six Mg(1,1) and six equivalent Mg(3) atoms to form AlMg12 cuboctahedra that share corners with six equivalent Al(1)Mg12 cuboctahedra; corners with twelve Mg(2,2,2)Mg10Cr2 cuboctahedra; edges with six Mg(1,1)Mg10Al2 cuboctahedra; edges with twelve equivalent Mg(3)Mg10AlCr cuboctahedra; faces with two equivalent Cr(1)Mg12 cuboctahedra; faces with six Mg(1,1)Mg10Al2 cuboctahedra; faces with six equivalent Mg(3)Mg10AlCr cuboctahedra; and faces with six equivalent Mg(4)Mg12 cuboctahedra.
Mg14CrAl 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 equivalent Mg(3); and two equivalent Al(1) atoms to form MgMg10Al2 cuboctahedra that share corners with four equivalent Cr(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Mg10Al2 cuboctahedra; corners with eight Mg(2,2)Mg10Cr2 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; edges with eight equivalent Mg(3)Mg10AlCr cuboctahedra; faces with two equivalent Mg(2)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; faces with four Mg(1,1)Mg10Al2 cuboctahedra; and faces with ten equivalent Mg(3)Mg10AlCr cuboctahedra. Both Mg(1)-Mg(4) bond lengths are 3.14 Å. There are two shorter (3.12 Å) and two longer (3.14 Å) Mg(1)-Mg(1,1) bond lengths. All Mg(1)-Mg(3) bond lengths are 3.15 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 Mg(2,2); four equivalent Mg(3); and two equivalent Cr(1) atoms to form MgMg10Cr2 cuboctahedra that share corners with four equivalent Al(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Mg10Cr2 cuboctahedra; corners with eight Mg(1,1)Mg10Al2 cuboctahedra; edges with two equivalent Cr(1)Mg12 cuboctahedra; edges with four Mg(2,2)Mg10Cr2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight equivalent Mg(3)Mg10AlCr cuboctahedra; faces with two equivalent Mg(1)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Cr(1)Mg12 cuboctahedra; faces with four Mg(2,2)Mg10Cr2 cuboctahedra; and faces with ten equivalent Mg(3)Mg10AlCr cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.14 Å. All Mg(2)-Mg(2,2) bond lengths are 3.13 Å. All Mg(2)-Mg(3) bond lengths are 3.14 Å. Both Mg(2)-Cr(1) bond lengths are 3.13 Å. In the third Mg site, Mg(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Al(1) atoms to form MgMg10Al2 cuboctahedra that share corners with four equivalent Cr(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Mg10Al2 cuboctahedra; corners with eight Mg(2,2)Mg10Cr2 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 equivalent Mg(3)Mg10AlCr cuboctahedra; faces with two equivalent Mg(2)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; faces with four equivalent Mg(1)Mg10Al2 cuboctahedra; and faces with ten equivalent Mg(3)Mg10AlCr cuboctahedra. Both Mg(1)-Mg(4) bond lengths are 3.14 Å. All Mg(1)-Mg(3) bond lengths are 3.15 Å. Both Mg(1)-Al(1) bond lengths are 3.13 Å. In the fourth Mg site, Mg(2) is bonded to two equivalent Mg(4); four Mg(2,2); four equivalent Mg(3); and two equivalent Cr(1) atoms to form MgMg10Cr2 cuboctahedra that share corners with four equivalent Al(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Mg10Cr2 cuboctahedra; corners with eight equivalent Mg(1)Mg10Al2 cuboctahedra; edges with two equivalent Cr(1)Mg12 cuboctahedra; edges with four Mg(2,2)Mg10Cr2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight equivalent Mg(3)Mg10AlCr cuboctahedra; faces with two equivalent Mg(1)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Cr(1)Mg12 cuboctahedra; faces with four Mg(2,2)Mg10Cr2 cuboctahedra; and faces with ten equivalent Mg(3)Mg10AlCr cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.14 Å. Both Mg(2)-Mg(2) bond lengths are 3.13 Å. All Mg(2)-Mg(3) bond lengths are 3.14 Å. Both Mg(2)-Cr(1) bond lengths are 3.13 Å. In the fifth Mg site, Mg(2) is bonded to two equivalent Mg(4); four Mg(2,2); four equivalent Mg(3); and two equivalent Cr(1) atoms to form MgMg10Cr2 cuboctahedra that share corners with four equivalent Al(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Mg10Cr2 cuboctahedra; corners with eight Mg(1,1)Mg10Al2 cuboctahedra; edges with two equivalent Cr(1)Mg12 cuboctahedra; edges with four Mg(2,2)Mg10Cr2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight equivalent Mg(3)Mg10AlCr cuboctahedra; faces with two equivalent Mg(1)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Cr(1)Mg12 cuboctahedra; faces with four Mg(2,2)Mg10Cr2 cuboctahedra; and faces with ten equivalent Mg(3)Mg10AlCr cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.14 Å. All Mg(2)-Mg(3) bond lengths are 3.14 Å. Both Mg(2)-Cr(1) bond lengths are 3.13 Å. In the sixth Mg site, Mg(3) is bonded to two Mg(1,1); two Mg(2,2); two equivalent Mg(4); four equivalent Mg(3); one Cr(1); and one Al(1) atom to form distorted MgMg10AlCr cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen equivalent Mg(3)Mg10AlCr cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Cr(1)Mg12 cuboctahedra; edges with two equivalent Al(1)Mg12 cuboctahedra; edges with four Mg(1,1)Mg10Al2 cuboctahedra; edges with four equivalent Mg(3)Mg10AlCr cuboctahedra; edges with four Mg(2,2)Mg10Cr2 cuboctahedra;  a faceface with one Cr(1)Mg12 cuboctahedra;  a faceface with one Al(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five Mg(1,1)Mg10Al2 cuboctahedra; faces with five Mg(2,2,2)Mg10Cr2 cuboctahedra; and faces with six equivalent Mg(3)Mg10AlCr cuboctahedra. Both Mg(3)-Mg(4) bond lengths are 3.13 Å. There are two shorter (3.10 Å) and two longer (3.16 Å) Mg(3)-Mg(3) bond lengths. The Mg(3)-Cr(1) bond length is 3.13 Å. The Mg(3)-Al(1) bond length is 3.13 Å. In the seventh Mg site, Mg(4) is bonded to three Mg(1,1); three Mg(2,2,2); and six equivalent Mg(3) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(4)Mg12 cuboctahedra; corners with twelve equivalent Mg(3)Mg10AlCr cuboctahedra; edges with six Mg(1,1)Mg10Al2 cuboctahedra; edges with six equivalent Mg(3)Mg10AlCr cuboctahedra; edges with six Mg(2,2,2)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with three Mg(1,1)Mg10Al2 cuboctahedra; faces with three Mg(2,2,2)Mg10Cr2 cuboctahedra; faces with three equivalent Cr(1)Mg12 cuboctahedra; faces with three equivalent Al(1)Mg12 cuboctahedra; and faces with six equivalent Mg(3)Mg10AlCr cuboctahedra. Cr(1) is bonded to six Mg(2,2,2) and six equivalent Mg(3) atoms to form CrMg12 cuboctahedra that share corners with six equivalent Cr(1)Mg12 cuboctahedra; corners with twelve Mg(1,1)Mg10Al2 cuboctahedra; edges with six Mg(2,2,2)Mg10Cr2 cuboctahedra; edges with twelve equivalent Mg(3)Mg10AlCr cuboctahedra; faces with two equivalent Al(1)Mg12 cuboctahedra; faces with six equivalent Mg(3)Mg10AlCr cuboctahedra; faces with six Mg(2,2,2)Mg10Cr2 cuboctahedra; and faces with six equivalent Mg(4)Mg12 cuboctahedra. Al(1) is bonded to six Mg(1,1) and six equivalent Mg(3) atoms to form AlMg12 cuboctahedra that share corners with six equivalent Al(1)Mg12 cuboctahedra; corners with twelve Mg(2,2,2)Mg10Cr2 cuboctahedra; edges with six Mg(1,1)Mg10Al2 cuboctahedra; edges with twelve equivalent Mg(3)Mg10AlCr cuboctahedra; faces with two equivalent Cr(1)Mg12 cuboctahedra; faces with six Mg(1,1)Mg10Al2 cuboctahedra; faces with six equivalent Mg(3)Mg10AlCr cuboctahedra; and faces with six equivalent Mg(4)Mg12 cuboctahedra.