MgGa crystallizes in the hexagonal P-6m2 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to three equivalent Mg(2), six equivalent Mg(1), and three equivalent Ga(2) atoms to form distorted MgMg9Ga3 cuboctahedra that share corners with six equivalent Ga(1)Ga12 cuboctahedra, corners with twelve equivalent Mg(1)Mg9Ga3 cuboctahedra, edges with six equivalent Mg(2)Mg12 cuboctahedra, edges with six equivalent Mg(1)Mg9Ga3 cuboctahedra,  a faceface with one Ga(1)Ga12 cuboctahedra, faces with six equivalent Mg(2)Mg12 cuboctahedra, and faces with seven equivalent Mg(1)Mg9Ga3 cuboctahedra. In the second Mg site, Mg(2) is bonded to six equivalent Mg(1) and six equivalent Mg(2) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(2)Mg12 cuboctahedra, edges with six equivalent Mg(2)Mg12 cuboctahedra, edges with twelve equivalent Mg(1)Mg9Ga3 cuboctahedra, faces with six equivalent Mg(2)Mg12 cuboctahedra, and faces with twelve equivalent Mg(1)Mg9Ga3 cuboctahedra. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to six equivalent Ga(1) and six equivalent Ga(2) atoms to form GaGa12 cuboctahedra that share corners with six equivalent Ga(1)Ga12 cuboctahedra, corners with twelve equivalent Mg(1)Mg9Ga3 cuboctahedra, edges with six equivalent Ga(1)Ga12 cuboctahedra, faces with two equivalent Mg(1)Mg9Ga3 cuboctahedra, and faces with six equivalent Ga(1)Ga12 cuboctahedra. In the second Ga site, Ga(2) is bonded in a 3-coordinate geometry to three equivalent Mg(1) and three equivalent Ga(1) atoms.
MgGa crystallizes in the hexagonal P-6m2 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to three equivalent Mg(2), six equivalent Mg(1), and three equivalent Ga(2) atoms to form distorted MgMg9Ga3 cuboctahedra that share corners with six equivalent Ga(1)Ga12 cuboctahedra, corners with twelve equivalent Mg(1)Mg9Ga3 cuboctahedra, edges with six equivalent Mg(2)Mg12 cuboctahedra, edges with six equivalent Mg(1)Mg9Ga3 cuboctahedra,  a faceface with one Ga(1)Ga12 cuboctahedra, faces with six equivalent Mg(2)Mg12 cuboctahedra, and faces with seven equivalent Mg(1)Mg9Ga3 cuboctahedra. All Mg(1)-Mg(2) bond lengths are 3.20 Å. All Mg(1)-Mg(1) bond lengths are 3.07 Å. All Mg(1)-Ga(2) bond lengths are 3.01 Å. In the second Mg site, Mg(2) is bonded to six equivalent Mg(1) and six equivalent Mg(2) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(2)Mg12 cuboctahedra, edges with six equivalent Mg(2)Mg12 cuboctahedra, edges with twelve equivalent Mg(1)Mg9Ga3 cuboctahedra, faces with six equivalent Mg(2)Mg12 cuboctahedra, and faces with twelve equivalent Mg(1)Mg9Ga3 cuboctahedra. All Mg(2)-Mg(2) bond lengths are 3.07 Å. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to six equivalent Ga(1) and six equivalent Ga(2) atoms to form GaGa12 cuboctahedra that share corners with six equivalent Ga(1)Ga12 cuboctahedra, corners with twelve equivalent Mg(1)Mg9Ga3 cuboctahedra, edges with six equivalent Ga(1)Ga12 cuboctahedra, faces with two equivalent Mg(1)Mg9Ga3 cuboctahedra, and faces with six equivalent Ga(1)Ga12 cuboctahedra. All Ga(1)-Ga(1) bond lengths are 3.07 Å. All Ga(1)-Ga(2) bond lengths are 3.12 Å. In the second Ga site, Ga(2) is bonded in a 3-coordinate geometry to three equivalent Mg(1) and three equivalent Ga(1) atoms.