Na3(CoO2)2 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to six equivalent O(1) atoms. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to four equivalent O(1) atoms. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a square co-planar geometry to four equivalent O(1) atoms. In the second Co site, Co(2) is bonded in a distorted square co-planar geometry to four equivalent O(1) atoms. O(1) is bonded to one Na(2), three equivalent Na(1), one Co(1), and one Co(2) atom to form a mixture of distorted edge, corner, and face-sharing ONa4Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-75°.
Na3(CoO2)2 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to six equivalent O(1) atoms. There are four shorter (2.50 Å) and two longer (2.61 Å) Na(1)-O(1) bond lengths. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to four equivalent O(1) atoms. All Na(2)-O(1) bond lengths are 2.30 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a square co-planar geometry to four equivalent O(1) atoms. All Co(1)-O(1) bond lengths are 1.87 Å. In the second Co site, Co(2) is bonded in a distorted square co-planar geometry to four equivalent O(1) atoms. All Co(2)-O(1) bond lengths are 1.92 Å. O(1) is bonded to one Na(2), three equivalent Na(1), one Co(1), and one Co(2) atom to form a mixture of distorted edge, corner, and face-sharing ONa4Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-75°.