Na(FeO2)2 crystallizes in the orthorhombic Pnma space group. Na(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), two equivalent O(4), and three equivalent O(2) atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 48-55°. In the second Fe site, Fe(2) is bonded to one O(4), two equivalent O(1), and three equivalent O(3) atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 48-55°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(1), one Fe(1), and two equivalent Fe(2) atoms to form a mixture of distorted edge and corner-sharing ONa2Fe3 trigonal bipyramids. In the second O site, O(2) is bonded to two equivalent Na(1) and three equivalent Fe(1) atoms to form a mixture of distorted edge and corner-sharing ONa2Fe3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Na(1) and three equivalent Fe(2) atoms to form a mixture of distorted edge and corner-sharing ONa2Fe3 square pyramids. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Na(1), one Fe(2), and two equivalent Fe(1) atoms.
Na(FeO2)2 crystallizes in the orthorhombic Pnma space group. Na(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. There is one shorter (2.54 Å) and one longer (2.57 Å) Na(1)-O(1) bond length. Both Na(1)-O(2) bond lengths are 2.43 Å. Both Na(1)-O(3) bond lengths are 2.42 Å. Both Na(1)-O(4) bond lengths are 2.59 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), two equivalent O(4), and three equivalent O(2) atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 48-55°. The Fe(1)-O(1) bond length is 2.04 Å. Both Fe(1)-O(4) bond lengths are 2.04 Å. There are two shorter (2.01 Å) and one longer (2.02 Å) Fe(1)-O(2) bond length. In the second Fe site, Fe(2) is bonded to one O(4), two equivalent O(1), and three equivalent O(3) atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 48-55°. The Fe(2)-O(4) bond length is 2.02 Å. Both Fe(2)-O(1) bond lengths are 2.01 Å. There are two shorter (2.02 Å) and one longer (2.04 Å) Fe(2)-O(3) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(1), one Fe(1), and two equivalent Fe(2) atoms to form a mixture of distorted edge and corner-sharing ONa2Fe3 trigonal bipyramids. In the second O site, O(2) is bonded to two equivalent Na(1) and three equivalent Fe(1) atoms to form a mixture of distorted edge and corner-sharing ONa2Fe3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Na(1) and three equivalent Fe(2) atoms to form a mixture of distorted edge and corner-sharing ONa2Fe3 square pyramids. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Na(1), one Fe(2), and two equivalent Fe(1) atoms.