Mg6ZrCu crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Zr(1), and two equivalent Cu(1) atoms to form distorted MgMg8Zr2Cu2 cuboctahedra that share corners with four equivalent Mg(2)Mg10Zr2 cuboctahedra, corners with ten equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, edges with two equivalent Mg(2)Mg10Zr2 cuboctahedra, edges with two equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, edges with four equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, edges with four equivalent Cu(1)Mg10Zr2 cuboctahedra, faces with two equivalent Mg(2)Mg10Zr2 cuboctahedra, faces with two equivalent Cu(1)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, and faces with eight equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Zr(1) atoms to form MgMg10Zr2 cuboctahedra that share corners with six equivalent Mg(2)Mg10Zr2 cuboctahedra, corners with eight equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, edges with four equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, edges with eight equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, faces with two equivalent Mg(2)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, faces with four equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, and faces with six equivalent Cu(1)Mg10Zr2 cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Zr(1), and two equivalent Cu(1) atoms to form distorted MgMg8Zr2Cu2 cuboctahedra that share corners with four equivalent Cu(1)Mg10Zr2 cuboctahedra, corners with ten equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, edges with two equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, edges with two equivalent Cu(1)Mg10Zr2 cuboctahedra, edges with four equivalent Mg(2)Mg10Zr2 cuboctahedra, edges with four equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, faces with two equivalent Mg(2)Mg10Zr2 cuboctahedra, faces with two equivalent Cu(1)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, and faces with eight equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra. In the fourth Mg site, Mg(4) is bonded in a distorted linear geometry to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Cu(1) atoms. Zr(1) is bonded in a distorted bent 120 degrees geometry to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Cu(1) atoms. Cu(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Zr(1) atoms to form distorted CuMg10Zr2 cuboctahedra that share corners with six equivalent Cu(1)Mg10Zr2 cuboctahedra, corners with eight equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, edges with four equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, edges with eight equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, faces with two equivalent Cu(1)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, faces with four equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, and faces with six equivalent Mg(2)Mg10Zr2 cuboctahedra.
Mg6ZrCu crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Zr(1), and two equivalent Cu(1) atoms to form distorted MgMg8Zr2Cu2 cuboctahedra that share corners with four equivalent Mg(2)Mg10Zr2 cuboctahedra, corners with ten equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, edges with two equivalent Mg(2)Mg10Zr2 cuboctahedra, edges with two equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, edges with four equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, edges with four equivalent Cu(1)Mg10Zr2 cuboctahedra, faces with two equivalent Mg(2)Mg10Zr2 cuboctahedra, faces with two equivalent Cu(1)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, and faces with eight equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra. There is one shorter (2.99 Å) and one longer (3.10 Å) Mg(1)-Mg(1) bond length. There is one shorter (3.09 Å) and one longer (3.28 Å) Mg(1)-Mg(2) bond length. Both Mg(1)-Mg(3) bond lengths are 3.00 Å. Both Mg(1)-Mg(4) bond lengths are 3.11 Å. There is one shorter (3.06 Å) and one longer (3.31 Å) Mg(1)-Zr(1) bond length. Both Mg(1)-Cu(1) bond lengths are 3.13 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Zr(1) atoms to form MgMg10Zr2 cuboctahedra that share corners with six equivalent Mg(2)Mg10Zr2 cuboctahedra, corners with eight equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, edges with four equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, edges with eight equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, faces with two equivalent Mg(2)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, faces with four equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, and faces with six equivalent Cu(1)Mg10Zr2 cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.02 Å. All Mg(2)-Mg(3) bond lengths are 3.06 Å. Both Mg(2)-Zr(1) bond lengths are 3.05 Å. In the third Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Zr(1), and two equivalent Cu(1) atoms to form distorted MgMg8Zr2Cu2 cuboctahedra that share corners with four equivalent Cu(1)Mg10Zr2 cuboctahedra, corners with ten equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, edges with two equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, edges with two equivalent Cu(1)Mg10Zr2 cuboctahedra, edges with four equivalent Mg(2)Mg10Zr2 cuboctahedra, edges with four equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, faces with two equivalent Mg(2)Mg10Zr2 cuboctahedra, faces with two equivalent Cu(1)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, and faces with eight equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra. There is one shorter (2.98 Å) and one longer (3.11 Å) Mg(3)-Mg(3) bond length. There is one shorter (3.15 Å) and one longer (3.22 Å) Mg(3)-Mg(4) bond length. Both Mg(3)-Zr(1) bond lengths are 3.11 Å. There is one shorter (3.02 Å) and one longer (3.35 Å) Mg(3)-Cu(1) bond length. In the fourth Mg site, Mg(4) is bonded in a distorted linear geometry to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Cu(1) atoms. Both Mg(4)-Cu(1) bond lengths are 3.05 Å. Zr(1) is bonded in a distorted bent 120 degrees geometry to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Cu(1) atoms. Both Zr(1)-Cu(1) bond lengths are 2.84 Å. Cu(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Zr(1) atoms to form distorted CuMg10Zr2 cuboctahedra that share corners with six equivalent Cu(1)Mg10Zr2 cuboctahedra, corners with eight equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, edges with four equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, edges with eight equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, faces with two equivalent Cu(1)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(1)Mg8Zr2Cu2 cuboctahedra, faces with four equivalent Mg(3)Mg8Zr2Cu2 cuboctahedra, and faces with six equivalent Mg(2)Mg10Zr2 cuboctahedra.