MgFe4CuO8 is Spinel-derived structured and crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Fe(1)O4 tetrahedra, edges with two equivalent Cu(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form FeO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with three equivalent Cu(1)O6 octahedra, and corners with six equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-60°. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with six equivalent Fe(1)O4 tetrahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Cu(1)O6 octahedra. Cu(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form CuO6 octahedra that share corners with six equivalent Fe(1)O4 tetrahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(1), and two equivalent Fe(2) atoms. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Fe(1), two equivalent Fe(2), and one Cu(1) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(1), one Fe(2), and one Cu(1) atom.
MgFe4CuO8 is Spinel-derived structured and crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Fe(1)O4 tetrahedra, edges with two equivalent Cu(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. Both Mg(1)-O(1) bond lengths are 2.12 Å. All Mg(1)-O(3) bond lengths are 2.09 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form FeO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with three equivalent Cu(1)O6 octahedra, and corners with six equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-60°. The Fe(1)-O(1) bond length is 1.96 Å. The Fe(1)-O(2) bond length is 1.92 Å. Both Fe(1)-O(3) bond lengths are 1.93 Å. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with six equivalent Fe(1)O4 tetrahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Cu(1)O6 octahedra. Both Fe(2)-O(1) bond lengths are 2.06 Å. Both Fe(2)-O(2) bond lengths are 2.04 Å. Both Fe(2)-O(3) bond lengths are 2.06 Å. Cu(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form CuO6 octahedra that share corners with six equivalent Fe(1)O4 tetrahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. Both Cu(1)-O(2) bond lengths are 2.35 Å. All Cu(1)-O(3) bond lengths are 2.00 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(1), and two equivalent Fe(2) atoms. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Fe(1), two equivalent Fe(2), and one Cu(1) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(1), one Fe(2), and one Cu(1) atom.