MgFeO2 crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(3), and two equivalent O(4) atoms. In the second Mg site, Mg(2) is bonded to one O(3), one O(4), and two equivalent O(2) atoms to form distorted corner-sharing MgO4 tetrahedra. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(3) atoms. In the second Fe site, Fe(2) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(2), and two equivalent O(4) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Fe(2), and two equivalent Fe(1) atoms to form distorted corner-sharing OMgFe3 trigonal pyramids. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Mg(2) and two equivalent Fe(2) atoms. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Mg(2), two equivalent Mg(1), and two equivalent Fe(1) atoms. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Mg(2), two equivalent Mg(1), and two equivalent Fe(2) atoms.
MgFeO2 crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(3), and two equivalent O(4) atoms. The Mg(1)-O(1) bond length is 2.15 Å. There is one shorter (1.82 Å) and one longer (2.54 Å) Mg(1)-O(3) bond length. There is one shorter (1.80 Å) and one longer (2.37 Å) Mg(1)-O(4) bond length. In the second Mg site, Mg(2) is bonded to one O(3), one O(4), and two equivalent O(2) atoms to form distorted corner-sharing MgO4 tetrahedra. The Mg(2)-O(3) bond length is 2.08 Å. The Mg(2)-O(4) bond length is 1.97 Å. There is one shorter (1.66 Å) and one longer (2.32 Å) Mg(2)-O(2) bond length. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(3) atoms. There is one shorter (1.89 Å) and one longer (2.07 Å) Fe(1)-O(1) bond length. There is one shorter (1.99 Å) and one longer (2.35 Å) Fe(1)-O(3) bond length. In the second Fe site, Fe(2) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(2), and two equivalent O(4) atoms. The Fe(2)-O(1) bond length is 2.10 Å. There is one shorter (1.77 Å) and one longer (2.51 Å) Fe(2)-O(2) bond length. There is one shorter (1.98 Å) and one longer (2.68 Å) Fe(2)-O(4) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Fe(2), and two equivalent Fe(1) atoms to form distorted corner-sharing OMgFe3 trigonal pyramids. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Mg(2) and two equivalent Fe(2) atoms. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Mg(2), two equivalent Mg(1), and two equivalent Fe(1) atoms. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Mg(2), two equivalent Mg(1), and two equivalent Fe(2) atoms.