Eu(MgGa)2 crystallizes in the tetragonal I4/mmm space group. Mg(1) is bonded to four equivalent Ga(1) atoms to form MgGa4 tetrahedra that share corners with eight equivalent Eu(1)Ga8 hexagonal bipyramids, corners with four equivalent Mg(1)Ga4 tetrahedra, edges with four equivalent Eu(1)Ga8 hexagonal bipyramids, and edges with four equivalent Mg(1)Ga4 tetrahedra. Eu(1) is bonded to eight equivalent Ga(1) atoms to form distorted EuGa8 hexagonal bipyramids that share corners with sixteen equivalent Mg(1)Ga4 tetrahedra, edges with four equivalent Eu(1)Ga8 hexagonal bipyramids, edges with eight equivalent Mg(1)Ga4 tetrahedra, and faces with four equivalent Eu(1)Ga8 hexagonal bipyramids. Ga(1) is bonded in a 9-coordinate geometry to four equivalent Mg(1), four equivalent Eu(1), and one Ga(1) atom.
Eu(MgGa)2 crystallizes in the tetragonal I4/mmm space group. Mg(1) is bonded to four equivalent Ga(1) atoms to form MgGa4 tetrahedra that share corners with eight equivalent Eu(1)Ga8 hexagonal bipyramids, corners with four equivalent Mg(1)Ga4 tetrahedra, edges with four equivalent Eu(1)Ga8 hexagonal bipyramids, and edges with four equivalent Mg(1)Ga4 tetrahedra. All Mg(1)-Ga(1) bond lengths are 2.79 Å. Eu(1) is bonded to eight equivalent Ga(1) atoms to form distorted EuGa8 hexagonal bipyramids that share corners with sixteen equivalent Mg(1)Ga4 tetrahedra, edges with four equivalent Eu(1)Ga8 hexagonal bipyramids, edges with eight equivalent Mg(1)Ga4 tetrahedra, and faces with four equivalent Eu(1)Ga8 hexagonal bipyramids. All Eu(1)-Ga(1) bond lengths are 3.38 Å. Ga(1) is bonded in a 9-coordinate geometry to four equivalent Mg(1), four equivalent Eu(1), and one Ga(1) atom. The Ga(1)-Ga(1) bond length is 2.45 Å.