Mg5Ga crystallizes in the monoclinic Cm space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 2-coordinate geometry to two equivalent Mg(2), two equivalent Mg(4), three equivalent Mg(5), and two equivalent Ga(1) atoms. In the second Mg site, Mg(2) is bonded in a 12-coordinate geometry to one Mg(5), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and three equivalent Ga(1) atoms. In the third Mg site, Mg(3) is bonded in a 2-coordinate geometry to two equivalent Mg(2), two equivalent Mg(5), three equivalent Mg(4), and two equivalent Ga(1) atoms. 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), three equivalent Mg(3), and one Ga(1) atom to form distorted MgMg11Ga cuboctahedra that share corners with six equivalent Mg(4)Mg11Ga cuboctahedra, edges with six equivalent Mg(5)Mg10Ga2 cuboctahedra, faces with two equivalent Mg(4)Mg11Ga cuboctahedra, and faces with three equivalent Mg(5)Mg10Ga2 cuboctahedra. In the fifth Mg site, Mg(5) is bonded to one Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(5), three equivalent Mg(1), and two equivalent Ga(1) atoms to form distorted MgMg10Ga2 cuboctahedra that share corners with six equivalent Mg(5)Mg10Ga2 cuboctahedra, edges with six equivalent Mg(4)Mg11Ga cuboctahedra, faces with two equivalent Mg(5)Mg10Ga2 cuboctahedra, and faces with three equivalent Mg(4)Mg11Ga cuboctahedra. Ga(1) is bonded in a 10-coordinate geometry to one Mg(4), two equivalent Mg(1), two equivalent Mg(3), two equivalent Mg(5), and three equivalent Mg(2) atoms.
Mg5Ga crystallizes in the monoclinic Cm space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 2-coordinate geometry to two equivalent Mg(2), two equivalent Mg(4), three equivalent Mg(5), and two equivalent Ga(1) atoms. Both Mg(1)-Mg(2) bond lengths are 3.09 Å. Both Mg(1)-Mg(4) bond lengths are 3.12 Å. There is one shorter (3.05 Å) and two longer (3.15 Å) Mg(1)-Mg(5) bond lengths. Both Mg(1)-Ga(1) bond lengths are 2.96 Å. In the second Mg site, Mg(2) is bonded in a 12-coordinate geometry to one Mg(5), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and three equivalent Ga(1) atoms. The Mg(2)-Mg(5) bond length is 2.97 Å. Both Mg(2)-Mg(2) bond lengths are 3.22 Å. Both Mg(2)-Mg(3) bond lengths are 3.10 Å. Both Mg(2)-Mg(4) bond lengths are 3.04 Å. There are two shorter (2.99 Å) and one longer (3.22 Å) Mg(2)-Ga(1) bond length. In the third Mg site, Mg(3) is bonded in a 2-coordinate geometry to two equivalent Mg(2), two equivalent Mg(5), three equivalent Mg(4), and two equivalent Ga(1) atoms. Both Mg(3)-Mg(5) bond lengths are 3.21 Å. There are two shorter (3.08 Å) and one longer (3.15 Å) Mg(3)-Mg(4) bond length. Both Mg(3)-Ga(1) bond lengths are 2.95 Å. 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), three equivalent Mg(3), and one Ga(1) atom to form distorted MgMg11Ga cuboctahedra that share corners with six equivalent Mg(4)Mg11Ga cuboctahedra, edges with six equivalent Mg(5)Mg10Ga2 cuboctahedra, faces with two equivalent Mg(4)Mg11Ga cuboctahedra, and faces with three equivalent Mg(5)Mg10Ga2 cuboctahedra. Both Mg(4)-Mg(4) bond lengths are 3.22 Å. Both Mg(4)-Mg(5) bond lengths are 3.09 Å. The Mg(4)-Ga(1) bond length is 3.07 Å. In the fifth Mg site, Mg(5) is bonded to one Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(5), three equivalent Mg(1), and two equivalent Ga(1) atoms to form distorted MgMg10Ga2 cuboctahedra that share corners with six equivalent Mg(5)Mg10Ga2 cuboctahedra, edges with six equivalent Mg(4)Mg11Ga cuboctahedra, faces with two equivalent Mg(5)Mg10Ga2 cuboctahedra, and faces with three equivalent Mg(4)Mg11Ga cuboctahedra. Both Mg(5)-Mg(5) bond lengths are 3.22 Å. Both Mg(5)-Ga(1) bond lengths are 3.07 Å. Ga(1) is bonded in a 10-coordinate geometry to one Mg(4), two equivalent Mg(1), two equivalent Mg(3), two equivalent Mg(5), and three equivalent Mg(2) atoms.