Mg14CrCu crystallizes in the orthorhombic Amm2 space group. There are seven 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 Cr(1)Mg10Cu2 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(5)Mg6CrCu cuboctahedra, corners with eight equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(5)Mg6CrCu cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Cu(1)Mg10Cr2 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(7)Mg11Cr 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 Mg(5)Mg6CrCu cuboctahedra, corners with four equivalent Cu(1)Mg10Cr2 cuboctahedra, corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(7)Mg11Cr cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(5)Mg6CrCu cuboctahedra, faces with two equivalent Mg(7)Mg11Cr cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Cr(1)Mg10Cu2 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with four equivalent Mg(5)Mg6CrCu cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), two equivalent Cr(1), and two equivalent Cu(1) atoms to form distorted MgMg8Cr2Cu2 cuboctahedra that share corners with two equivalent Mg(5)Mg6CrCu cuboctahedra, 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)Mg8Cr2Cu2 cuboctahedra, edges with two equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, edges with two equivalent Cr(1)Mg10Cu2 cuboctahedra, edges with two equivalent Cu(1)Mg10Cr2 cuboctahedra, edges with four equivalent Mg(7)Mg11Cr cuboctahedra, edges with four equivalent Mg(5)Mg6CrCu cuboctahedra, faces with two equivalent Mg(7)Mg11Cr cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, faces with two equivalent Cr(1)Mg10Cu2 cuboctahedra, faces with two equivalent Cu(1)Mg10Cr2 cuboctahedra, and faces with six equivalent Mg(5)Mg6CrCu 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 two equivalent Mg(5)Mg6CrCu cuboctahedra, corners with four equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, corners with four equivalent Cr(1)Mg10Cu2 cuboctahedra, corners with four equivalent Cu(1)Mg10Cr2 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(7)Mg11Cr cuboctahedra, edges with four equivalent Mg(5)Mg6CrCu cuboctahedra, faces with two equivalent Mg(7)Mg11Cr 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)Mg8Cr2Cu2 cuboctahedra, and faces with six equivalent Mg(5)Mg6CrCu cuboctahedra. In the fifth Mg site, Mg(5) is bonded to one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(7), one Cr(1), and one Cu(1) atom to form distorted MgMg6CrCu cuboctahedra that share  a cornercorner with one Mg(2)Mg12 cuboctahedra,  a cornercorner with one Mg(4)Mg12 cuboctahedra,  a cornercorner with one Mg(3)Mg8Cr2Cu2 cuboctahedra,  a cornercorner with one Cr(1)Mg10Cu2 cuboctahedra, corners with two equivalent Mg(1)Mg12 cuboctahedra, corners with two equivalent Cu(1)Mg10Cr2 cuboctahedra, corners with four equivalent Mg(7)Mg11Cr cuboctahedra, corners with eight equivalent Mg(5)Mg6CrCu cuboctahedra,  an edgeedge with one Mg(1)Mg12 cuboctahedra,  an edgeedge with one Mg(2)Mg12 cuboctahedra,  an edgeedge with one Cr(1)Mg10Cu2 cuboctahedra,  an edgeedge with one Cu(1)Mg10Cr2 cuboctahedra, edges with two equivalent Mg(7)Mg11Cr cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra,  a faceface with one Cr(1)Mg10Cu2 cuboctahedra, faces with three equivalent Mg(4)Mg12 cuboctahedra, faces with three equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, and faces with four equivalent Mg(5)Mg6CrCu cuboctahedra. In the sixth Mg site, Mg(6) is bonded in a distorted single-bond geometry to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(7), and one Cu(1) atom. In the seventh Mg site, Mg(7) is bonded to one Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(6), four equivalent Mg(5), and one Cr(1) atom to form distorted MgMg11Cr cuboctahedra that share corners with six equivalent Mg(7)Mg11Cr cuboctahedra, corners with eight equivalent Mg(5)Mg6CrCu cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Cr(1)Mg10Cu2 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(5)Mg6CrCu cuboctahedra, edges with four equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra,  a faceface with one Cr(1)Mg10Cu2 cuboctahedra, faces with two equivalent Mg(7)Mg11Cr cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, faces with three equivalent Mg(1)Mg12 cuboctahedra, and faces with three equivalent Cu(1)Mg10Cr2 cuboctahedra. Cr(1) is bonded to two equivalent Mg(7), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Cu(1) atoms to form CrMg10Cu2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(5)Mg6CrCu cuboctahedra, corners with six equivalent Cr(1)Mg10Cu2 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Cu(1)Mg10Cr2 cuboctahedra, edges with four equivalent Mg(7)Mg11Cr cuboctahedra, edges with four equivalent Mg(5)Mg6CrCu cuboctahedra, edges with four equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, faces with two equivalent Mg(7)Mg11Cr cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Cu(1)Mg10Cr2 cuboctahedra, faces with four equivalent Mg(5)Mg6CrCu cuboctahedra, and faces with four equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra. Cu(1) is bonded to two equivalent Mg(6), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Cr(1) atoms to form CuMg10Cr2 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with six equivalent Cu(1)Mg10Cr2 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, corners with eight equivalent Mg(5)Mg6CrCu cuboctahedra, edges with two equivalent Cr(1)Mg10Cu2 cuboctahedra, edges with four equivalent Mg(5)Mg6CrCu cuboctahedra, edges with four equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Cr(1)Mg10Cu2 cuboctahedra, faces with four equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, and faces with six equivalent Mg(7)Mg11Cr cuboctahedra.
Mg14CrCu crystallizes in the orthorhombic Amm2 space group. There are seven 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 Cr(1)Mg10Cu2 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(5)Mg6CrCu cuboctahedra, corners with eight equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(5)Mg6CrCu cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Cu(1)Mg10Cr2 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(7)Mg11Cr cuboctahedra. Both Mg(1)-Mg(2) bond lengths are 3.13 Å. Both Mg(1)-Mg(6) bond lengths are 3.12 Å. There are two shorter (3.11 Å) and two longer (3.14 Å) Mg(1)-Mg(4) bond lengths. All Mg(1)-Mg(5) bond lengths are 3.18 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 Mg(5)Mg6CrCu cuboctahedra, corners with four equivalent Cu(1)Mg10Cr2 cuboctahedra, corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(7)Mg11Cr cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(5)Mg6CrCu cuboctahedra, faces with two equivalent Mg(7)Mg11Cr cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Cr(1)Mg10Cu2 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with four equivalent Mg(5)Mg6CrCu cuboctahedra. Both Mg(2)-Mg(7) bond lengths are 3.09 Å. There are two shorter (3.10 Å) and two longer (3.15 Å) Mg(2)-Mg(4) bond lengths. All Mg(2)-Mg(5) bond lengths are 3.19 Å. In the third Mg site, Mg(3) is bonded to two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), two equivalent Cr(1), and two equivalent Cu(1) atoms to form distorted MgMg8Cr2Cu2 cuboctahedra that share corners with two equivalent Mg(5)Mg6CrCu cuboctahedra, 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)Mg8Cr2Cu2 cuboctahedra, edges with two equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, edges with two equivalent Cr(1)Mg10Cu2 cuboctahedra, edges with two equivalent Cu(1)Mg10Cr2 cuboctahedra, edges with four equivalent Mg(7)Mg11Cr cuboctahedra, edges with four equivalent Mg(5)Mg6CrCu cuboctahedra, faces with two equivalent Mg(7)Mg11Cr cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, faces with two equivalent Cr(1)Mg10Cu2 cuboctahedra, faces with two equivalent Cu(1)Mg10Cr2 cuboctahedra, and faces with six equivalent Mg(5)Mg6CrCu cuboctahedra. There is one shorter (3.09 Å) and one longer (3.18 Å) Mg(3)-Mg(3) bond length. Both Mg(3)-Mg(5) bond lengths are 3.01 Å. Both Mg(3)-Mg(6) bond lengths are 3.05 Å. Both Mg(3)-Mg(7) bond lengths are 3.06 Å. There is one shorter (3.08 Å) and one longer (3.17 Å) Mg(3)-Cr(1) bond length. There is one shorter (3.12 Å) and one longer (3.13 Å) Mg(3)-Cu(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 two equivalent Mg(5)Mg6CrCu cuboctahedra, corners with four equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, corners with four equivalent Cr(1)Mg10Cu2 cuboctahedra, corners with four equivalent Cu(1)Mg10Cr2 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(7)Mg11Cr cuboctahedra, edges with four equivalent Mg(5)Mg6CrCu cuboctahedra, faces with two equivalent Mg(7)Mg11Cr 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)Mg8Cr2Cu2 cuboctahedra, and faces with six equivalent Mg(5)Mg6CrCu cuboctahedra. There is one shorter (3.13 Å) and one longer (3.14 Å) Mg(4)-Mg(4) bond length. Both Mg(4)-Mg(5) bond lengths are 3.21 Å. Both Mg(4)-Mg(6) bond lengths are 3.14 Å. Both Mg(4)-Mg(7) bond lengths are 3.11 Å. In the fifth Mg site, Mg(5) is bonded to one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(7), one Cr(1), and one Cu(1) atom to form distorted MgMg6CrCu cuboctahedra that share  a cornercorner with one Mg(2)Mg12 cuboctahedra,  a cornercorner with one Mg(4)Mg12 cuboctahedra,  a cornercorner with one Mg(3)Mg8Cr2Cu2 cuboctahedra,  a cornercorner with one Cr(1)Mg10Cu2 cuboctahedra, corners with two equivalent Mg(1)Mg12 cuboctahedra, corners with two equivalent Cu(1)Mg10Cr2 cuboctahedra, corners with four equivalent Mg(7)Mg11Cr cuboctahedra, corners with eight equivalent Mg(5)Mg6CrCu cuboctahedra,  an edgeedge with one Mg(1)Mg12 cuboctahedra,  an edgeedge with one Mg(2)Mg12 cuboctahedra,  an edgeedge with one Cr(1)Mg10Cu2 cuboctahedra,  an edgeedge with one Cu(1)Mg10Cr2 cuboctahedra, edges with two equivalent Mg(7)Mg11Cr cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra,  a faceface with one Cr(1)Mg10Cu2 cuboctahedra, faces with three equivalent Mg(4)Mg12 cuboctahedra, faces with three equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, and faces with four equivalent Mg(5)Mg6CrCu cuboctahedra. There is one shorter (3.07 Å) and one longer (3.18 Å) Mg(5)-Mg(7) bond length. The Mg(5)-Cr(1) bond length is 2.97 Å. The Mg(5)-Cu(1) bond length is 2.96 Å. In the sixth Mg site, Mg(6) is bonded in a distorted single-bond geometry to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(7), and one Cu(1) atom. Both Mg(6)-Mg(7) bond lengths are 3.13 Å. The Mg(6)-Cu(1) bond length is 3.02 Å. In the seventh Mg site, Mg(7) is bonded to one Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(6), four equivalent Mg(5), and one Cr(1) atom to form distorted MgMg11Cr cuboctahedra that share corners with six equivalent Mg(7)Mg11Cr cuboctahedra, corners with eight equivalent Mg(5)Mg6CrCu cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Cr(1)Mg10Cu2 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(5)Mg6CrCu cuboctahedra, edges with four equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra,  a faceface with one Cr(1)Mg10Cu2 cuboctahedra, faces with two equivalent Mg(7)Mg11Cr cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, faces with three equivalent Mg(1)Mg12 cuboctahedra, and faces with three equivalent Cu(1)Mg10Cr2 cuboctahedra. The Mg(7)-Cr(1) bond length is 3.04 Å. Cr(1) is bonded to two equivalent Mg(7), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Cu(1) atoms to form CrMg10Cu2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(5)Mg6CrCu cuboctahedra, corners with six equivalent Cr(1)Mg10Cu2 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Cu(1)Mg10Cr2 cuboctahedra, edges with four equivalent Mg(7)Mg11Cr cuboctahedra, edges with four equivalent Mg(5)Mg6CrCu cuboctahedra, edges with four equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, faces with two equivalent Mg(7)Mg11Cr cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Cu(1)Mg10Cr2 cuboctahedra, faces with four equivalent Mg(5)Mg6CrCu cuboctahedra, and faces with four equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra. Both Cr(1)-Cu(1) bond lengths are 3.13 Å. Cu(1) is bonded to two equivalent Mg(6), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Cr(1) atoms to form CuMg10Cr2 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with six equivalent Cu(1)Mg10Cr2 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, corners with eight equivalent Mg(5)Mg6CrCu cuboctahedra, edges with two equivalent Cr(1)Mg10Cu2 cuboctahedra, edges with four equivalent Mg(5)Mg6CrCu cuboctahedra, edges with four equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Cr(1)Mg10Cu2 cuboctahedra, faces with four equivalent Mg(3)Mg8Cr2Cu2 cuboctahedra, and faces with six equivalent Mg(7)Mg11Cr cuboctahedra.