MgMn2O4 crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with six equivalent Mn(4)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-19°. In the second Mg site, Mg(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with six equivalent Mn(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(3)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-10°. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(3)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. In the second Mn site, Mn(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with six equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(3)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-10°. In the third Mn site, Mn(3) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form MnO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. In the fourth Mn site, Mn(4) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-19°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to one Mg(1), one Mn(1), one Mn(3), and one Mn(4) atom. In the second O site, O(2) is bonded to one Mg(1), one Mg(2), one Mn(1), one Mn(2), and one Mn(4) atom to form a mixture of corner and edge-sharing OMg2Mn3 square pyramids. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mn(1), one Mn(2), and one Mn(3) atom. In the fourth O site, O(4) is bonded to one Mg(1), one Mg(2), one Mn(2), one Mn(3), and one Mn(4) atom to form a mixture of corner and edge-sharing OMg2Mn3 square pyramids.
MgMn2O4 crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with six equivalent Mn(4)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-19°. Both Mg(1)-O(1) bond lengths are 2.07 Å. Both Mg(1)-O(2) bond lengths are 2.09 Å. Both Mg(1)-O(4) bond lengths are 2.22 Å. In the second Mg site, Mg(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with six equivalent Mn(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(3)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-10°. Both Mg(2)-O(2) bond lengths are 2.12 Å. Both Mg(2)-O(3) bond lengths are 2.23 Å. Both Mg(2)-O(4) bond lengths are 2.24 Å. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(3)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. Both Mn(1)-O(1) bond lengths are 1.98 Å. Both Mn(1)-O(2) bond lengths are 1.93 Å. Both Mn(1)-O(3) bond lengths are 2.25 Å. In the second Mn site, Mn(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with six equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(3)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-10°. Both Mn(2)-O(2) bond lengths are 2.43 Å. Both Mn(2)-O(3) bond lengths are 1.96 Å. Both Mn(2)-O(4) bond lengths are 2.02 Å. In the third Mn site, Mn(3) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form MnO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. Both Mn(3)-O(1) bond lengths are 1.95 Å. Both Mn(3)-O(3) bond lengths are 1.94 Å. Both Mn(3)-O(4) bond lengths are 1.95 Å. In the fourth Mn site, Mn(4) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-19°. Both Mn(4)-O(1) bond lengths are 2.16 Å. Both Mn(4)-O(2) bond lengths are 2.19 Å. Both Mn(4)-O(4) bond lengths are 2.33 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to one Mg(1), one Mn(1), one Mn(3), and one Mn(4) atom. In the second O site, O(2) is bonded to one Mg(1), one Mg(2), one Mn(1), one Mn(2), and one Mn(4) atom to form a mixture of corner and edge-sharing OMg2Mn3 square pyramids. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mn(1), one Mn(2), and one Mn(3) atom. In the fourth O site, O(4) is bonded to one Mg(1), one Mg(2), one Mn(2), one Mn(3), and one Mn(4) atom to form a mixture of corner and edge-sharing OMg2Mn3 square pyramids.