MgGa2 crystallizes in the trigonal R32 space group. Mg(1) is bonded to three equivalent Mg(1), three equivalent Ga(2), and six equivalent Ga(1) atoms to form distorted MgMg3Ga9 cuboctahedra that share corners with six equivalent Ga(2)Mg6Ga6 cuboctahedra, corners with twelve equivalent Mg(1)Mg3Ga9 cuboctahedra, edges with six equivalent Mg(1)Mg3Ga9 cuboctahedra, faces with four equivalent Mg(1)Mg3Ga9 cuboctahedra, and faces with four equivalent Ga(2)Mg6Ga6 cuboctahedra. There are two inequivalent Ga sites. In the first Ga site, Ga(2) is bonded to six equivalent Mg(1) and six equivalent Ga(1) atoms to form GaMg6Ga6 cuboctahedra that share corners with six equivalent Ga(2)Mg6Ga6 cuboctahedra, corners with twelve equivalent Mg(1)Mg3Ga9 cuboctahedra, edges with six equivalent Ga(2)Mg6Ga6 cuboctahedra, and faces with eight equivalent Mg(1)Mg3Ga9 cuboctahedra. In the second Ga site, Ga(1) is bonded in a 4-coordinate geometry to four equivalent Mg(1) and two equivalent Ga(2) atoms.
MgGa2 crystallizes in the trigonal R32 space group. Mg(1) is bonded to three equivalent Mg(1), three equivalent Ga(2), and six equivalent Ga(1) atoms to form distorted MgMg3Ga9 cuboctahedra that share corners with six equivalent Ga(2)Mg6Ga6 cuboctahedra, corners with twelve equivalent Mg(1)Mg3Ga9 cuboctahedra, edges with six equivalent Mg(1)Mg3Ga9 cuboctahedra, faces with four equivalent Mg(1)Mg3Ga9 cuboctahedra, and faces with four equivalent Ga(2)Mg6Ga6 cuboctahedra. All Mg(1)-Mg(1) bond lengths are 3.04 Å. All Mg(1)-Ga(2) bond lengths are 3.04 Å. There are three shorter (2.89 Å) and three longer (2.91 Å) Mg(1)-Ga(1) bond lengths. There are two inequivalent Ga sites. In the first Ga site, Ga(2) is bonded to six equivalent Mg(1) and six equivalent Ga(1) atoms to form GaMg6Ga6 cuboctahedra that share corners with six equivalent Ga(2)Mg6Ga6 cuboctahedra, corners with twelve equivalent Mg(1)Mg3Ga9 cuboctahedra, edges with six equivalent Ga(2)Mg6Ga6 cuboctahedra, and faces with eight equivalent Mg(1)Mg3Ga9 cuboctahedra. All Ga(2)-Ga(1) bond lengths are 2.90 Å. In the second Ga site, Ga(1) is bonded in a 4-coordinate geometry to four equivalent Mg(1) and two equivalent Ga(2) atoms.