Mg6CuBi crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 3-coordinate geometry to two equivalent Mg(2), two equivalent Mg(3), one Cu(1), and two equivalent Bi(1) atoms. 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 Cu(1) atoms to form a mixture of distorted corner and face-sharing MgMg10Cu2 cuboctahedra. In the third Mg site, Mg(3) is bonded in a 12-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cu(1), and two equivalent Bi(1) atoms. In the fourth Mg site, Mg(4) is bonded in a distorted linear geometry to two equivalent Mg(2), four equivalent Mg(3), and two equivalent Bi(1) atoms. Cu(1) is bonded in a 8-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), and four equivalent Mg(3) atoms. Bi(1) is bonded in a 10-coordinate geometry to two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms.
Mg6CuBi crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 3-coordinate geometry to two equivalent Mg(2), two equivalent Mg(3), one Cu(1), and two equivalent Bi(1) atoms. There is one shorter (3.25 Å) and one longer (3.27 Å) Mg(1)-Mg(2) bond length. Both Mg(1)-Mg(3) bond lengths are 3.15 Å. The Mg(1)-Cu(1) bond length is 2.68 Å. Both Mg(1)-Bi(1) bond lengths are 3.14 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 Cu(1) atoms to form a mixture of distorted corner and face-sharing MgMg10Cu2 cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.10 Å. All Mg(2)-Mg(3) bond lengths are 3.13 Å. Both Mg(2)-Cu(1) bond lengths are 3.16 Å. In the third Mg site, Mg(3) is bonded in a 12-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cu(1), and two equivalent Bi(1) atoms. There is one shorter (2.99 Å) and one longer (3.22 Å) Mg(3)-Mg(3) bond length. There is one shorter (3.19 Å) and one longer (3.33 Å) Mg(3)-Mg(4) bond length. Both Mg(3)-Cu(1) bond lengths are 2.94 Å. There is one shorter (3.18 Å) and one longer (3.34 Å) Mg(3)-Bi(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(3), and two equivalent Bi(1) atoms. Both Mg(4)-Bi(1) bond lengths are 3.10 Å. Cu(1) is bonded in a 8-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), and four equivalent Mg(3) atoms. Bi(1) is bonded in a 10-coordinate geometry to two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms.