MgGa4(CuO4)2 crystallizes in the tetragonal I-4m2 space group. Mg(1) is bonded to four equivalent Ga(1) and four equivalent O(2) atoms to form MgGa4O4 tetrahedra that share corners with four equivalent Cu(2)O4 tetrahedra. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a tetrahedral geometry to four equivalent O(1) atoms. In the second Cu site, Cu(2) is bonded to four equivalent O(2) atoms to form CuO4 tetrahedra that share corners with four equivalent Mg(1)Ga4O4 tetrahedra. Ga(1) is bonded in a 7-coordinate geometry to one Mg(1), three equivalent O(1), and three equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Cu(1) and three equivalent Ga(1) atoms. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Mg(1), one Cu(2), and three equivalent Ga(1) atoms.
MgGa4(CuO4)2 crystallizes in the tetragonal I-4m2 space group. Mg(1) is bonded to four equivalent Ga(1) and four equivalent O(2) atoms to form MgGa4O4 tetrahedra that share corners with four equivalent Cu(2)O4 tetrahedra. All Mg(1)-Ga(1) bond lengths are 2.26 Å. All Mg(1)-O(2) bond lengths are 1.86 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a tetrahedral geometry to four equivalent O(1) atoms. All Cu(1)-O(1) bond lengths are 2.25 Å. In the second Cu site, Cu(2) is bonded to four equivalent O(2) atoms to form CuO4 tetrahedra that share corners with four equivalent Mg(1)Ga4O4 tetrahedra. All Cu(2)-O(2) bond lengths are 2.11 Å. Ga(1) is bonded in a 7-coordinate geometry to one Mg(1), three equivalent O(1), and three equivalent O(2) atoms. All Ga(1)-O(1) bond lengths are 1.97 Å. There are two shorter (2.39 Å) and one longer (2.42 Å) Ga(1)-O(2) bond length. There are two inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Cu(1) and three equivalent Ga(1) atoms. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Mg(1), one Cu(2), and three equivalent Ga(1) atoms.