Na(NiO2)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 Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), two equivalent O(4), and three equivalent O(2) atoms to form a mixture of distorted edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 49-58°. In the second Ni site, Ni(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 NiO6 octahedra. The corner-sharing octahedral tilt angles range from 49-58°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Na(1), one Ni(1), and two equivalent Ni(2) atoms. In the second O site, O(2) is bonded to two equivalent Na(1) and three equivalent Ni(1) atoms to form a mixture of distorted edge and corner-sharing ONa2Ni3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Na(1) and three equivalent Ni(2) atoms to form a mixture of edge and corner-sharing ONa2Ni3 square pyramids. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Na(1), one Ni(2), and two equivalent Ni(1) atoms.
Na(NiO2)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 (2.43 Å) and one longer (2.47 Å) Na(1)-O(1) bond length. Both Na(1)-O(2) bond lengths are 2.38 Å. Both Na(1)-O(3) bond lengths are 2.40 Å. Both Na(1)-O(4) bond lengths are 2.46 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), two equivalent O(4), and three equivalent O(2) atoms to form a mixture of distorted edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 49-58°. The Ni(1)-O(1) bond length is 2.20 Å. Both Ni(1)-O(4) bond lengths are 1.92 Å. There are two shorter (1.90 Å) and one longer (2.05 Å) Ni(1)-O(2) bond length. In the second Ni site, Ni(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 NiO6 octahedra. The corner-sharing octahedral tilt angles range from 49-58°. The Ni(2)-O(4) bond length is 1.99 Å. Both Ni(2)-O(1) bond lengths are 1.89 Å. There are two shorter (1.91 Å) and one longer (1.99 Å) Ni(2)-O(3) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Na(1), one Ni(1), and two equivalent Ni(2) atoms. In the second O site, O(2) is bonded to two equivalent Na(1) and three equivalent Ni(1) atoms to form a mixture of distorted edge and corner-sharing ONa2Ni3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Na(1) and three equivalent Ni(2) atoms to form a mixture of edge and corner-sharing ONa2Ni3 square pyramids. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Na(1), one Ni(2), and two equivalent Ni(1) atoms.