MgMn3CuO8 is beta indium sulfide-derived structured and crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form MgO4 tetrahedra that share corners with three equivalent Mn(2)O6 octahedra, corners with three equivalent Cu(1)O6 octahedra, and corners with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-63°. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form MnO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Cu(1)O6 octahedra. In the second Mn site, Mn(2) is bonded to one O(1), one O(6), two equivalent O(2), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Cu(1)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. Cu(1) is bonded to one O(3), one O(5), two equivalent O(2), and two equivalent O(4) atoms to form CuO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Mn(2) and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Mn(1), one Mn(2), and one Cu(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent Mn(1) and one Cu(1) atom. In the fourth O site, O(4) is bonded to one Mg(1), one Mn(1), one Mn(2), and one Cu(1) atom to form a mixture of distorted corner and edge-sharing OMgMn2Cu tetrahedra. In the fifth O site, O(5) is bonded to one Mg(1), two equivalent Mn(1), and one Cu(1) atom to form a mixture of distorted corner and edge-sharing OMgMn2Cu trigonal pyramids. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Mn(2), and two equivalent Mn(1) atoms.
MgMn3CuO8 is beta indium sulfide-derived structured and crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form MgO4 tetrahedra that share corners with three equivalent Mn(2)O6 octahedra, corners with three equivalent Cu(1)O6 octahedra, and corners with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-63°. The Mg(1)-O(5) bond length is 2.03 Å. The Mg(1)-O(6) bond length is 2.00 Å. Both Mg(1)-O(4) bond lengths are 1.99 Å. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form MnO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Cu(1)O6 octahedra. The Mn(1)-O(1) bond length is 1.91 Å. The Mn(1)-O(2) bond length is 1.90 Å. The Mn(1)-O(3) bond length is 1.92 Å. The Mn(1)-O(4) bond length is 1.98 Å. The Mn(1)-O(5) bond length is 1.99 Å. The Mn(1)-O(6) bond length is 1.98 Å. In the second Mn site, Mn(2) is bonded to one O(1), one O(6), two equivalent O(2), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Cu(1)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. The Mn(2)-O(1) bond length is 2.17 Å. The Mn(2)-O(6) bond length is 2.18 Å. Both Mn(2)-O(2) bond lengths are 1.94 Å. Both Mn(2)-O(4) bond lengths are 1.97 Å. Cu(1) is bonded to one O(3), one O(5), two equivalent O(2), and two equivalent O(4) atoms to form CuO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. The Cu(1)-O(3) bond length is 2.06 Å. The Cu(1)-O(5) bond length is 2.10 Å. Both Cu(1)-O(2) bond lengths are 2.01 Å. Both Cu(1)-O(4) bond lengths are 2.05 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Mn(2) and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Mn(1), one Mn(2), and one Cu(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent Mn(1) and one Cu(1) atom. In the fourth O site, O(4) is bonded to one Mg(1), one Mn(1), one Mn(2), and one Cu(1) atom to form a mixture of distorted corner and edge-sharing OMgMn2Cu tetrahedra. In the fifth O site, O(5) is bonded to one Mg(1), two equivalent Mn(1), and one Cu(1) atom to form a mixture of distorted corner and edge-sharing OMgMn2Cu trigonal pyramids. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Mn(2), and two equivalent Mn(1) atoms.