Mg5Ga crystallizes in the trigonal R32 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to four equivalent Mg(2), six equivalent Mg(1), and two equivalent Ga(1) atoms to form distorted MgMg10Ga2 cuboctahedra that share corners with eighteen equivalent Mg(1)Mg10Ga2 cuboctahedra, edges with four equivalent Ga(1)Mg12 cuboctahedra, edges with six equivalent Mg(1)Mg10Ga2 cuboctahedra, edges with eight equivalent Mg(2)Mg9Ga3 cuboctahedra, faces with four equivalent Ga(1)Mg12 cuboctahedra, faces with eight equivalent Mg(1)Mg10Ga2 cuboctahedra, and faces with eight equivalent Mg(2)Mg9Ga3 cuboctahedra. In the second Mg site, Mg(2) is bonded to three equivalent Mg(2), six equivalent Mg(1), and three equivalent Ga(1) atoms to form distorted MgMg9Ga3 cuboctahedra that share corners with six equivalent Ga(1)Mg12 cuboctahedra, corners with twelve equivalent Mg(2)Mg9Ga3 cuboctahedra, edges with six equivalent Mg(2)Mg9Ga3 cuboctahedra, edges with twelve equivalent Mg(1)Mg10Ga2 cuboctahedra, faces with four equivalent Mg(2)Mg9Ga3 cuboctahedra, faces with four equivalent Ga(1)Mg12 cuboctahedra, and faces with twelve equivalent Mg(1)Mg10Ga2 cuboctahedra. Ga(1) is bonded to six equivalent Mg(1) and six equivalent Mg(2) atoms to form GaMg12 cuboctahedra that share corners with six equivalent Ga(1)Mg12 cuboctahedra, corners with twelve equivalent Mg(2)Mg9Ga3 cuboctahedra, edges with six equivalent Ga(1)Mg12 cuboctahedra, edges with twelve equivalent Mg(1)Mg10Ga2 cuboctahedra, faces with eight equivalent Mg(2)Mg9Ga3 cuboctahedra, and faces with twelve equivalent Mg(1)Mg10Ga2 cuboctahedra.
Mg5Ga crystallizes in the trigonal R32 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to four equivalent Mg(2), six equivalent Mg(1), and two equivalent Ga(1) atoms to form distorted MgMg10Ga2 cuboctahedra that share corners with eighteen equivalent Mg(1)Mg10Ga2 cuboctahedra, edges with four equivalent Ga(1)Mg12 cuboctahedra, edges with six equivalent Mg(1)Mg10Ga2 cuboctahedra, edges with eight equivalent Mg(2)Mg9Ga3 cuboctahedra, faces with four equivalent Ga(1)Mg12 cuboctahedra, faces with eight equivalent Mg(1)Mg10Ga2 cuboctahedra, and faces with eight equivalent Mg(2)Mg9Ga3 cuboctahedra. There are two shorter (3.08 Å) and two longer (3.11 Å) Mg(1)-Mg(2) bond lengths. There are four shorter (3.08 Å) and two longer (3.16 Å) Mg(1)-Mg(1) bond lengths. Both Mg(1)-Ga(1) bond lengths are 3.08 Å. In the second Mg site, Mg(2) is bonded to three equivalent Mg(2), six equivalent Mg(1), and three equivalent Ga(1) atoms to form distorted MgMg9Ga3 cuboctahedra that share corners with six equivalent Ga(1)Mg12 cuboctahedra, corners with twelve equivalent Mg(2)Mg9Ga3 cuboctahedra, edges with six equivalent Mg(2)Mg9Ga3 cuboctahedra, edges with twelve equivalent Mg(1)Mg10Ga2 cuboctahedra, faces with four equivalent Mg(2)Mg9Ga3 cuboctahedra, faces with four equivalent Ga(1)Mg12 cuboctahedra, and faces with twelve equivalent Mg(1)Mg10Ga2 cuboctahedra. All Mg(2)-Mg(2) bond lengths are 3.10 Å. All Mg(2)-Ga(1) bond lengths are 3.10 Å. Ga(1) is bonded to six equivalent Mg(1) and six equivalent Mg(2) atoms to form GaMg12 cuboctahedra that share corners with six equivalent Ga(1)Mg12 cuboctahedra, corners with twelve equivalent Mg(2)Mg9Ga3 cuboctahedra, edges with six equivalent Ga(1)Mg12 cuboctahedra, edges with twelve equivalent Mg(1)Mg10Ga2 cuboctahedra, faces with eight equivalent Mg(2)Mg9Ga3 cuboctahedra, and faces with twelve equivalent Mg(1)Mg10Ga2 cuboctahedra.