Na3(CoO2)4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted NaO6 octahedra that share corners with six equivalent Co(1)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with two equivalent Co(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-17°. In the second Na site, Na(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form distorted NaO6 octahedra that share corners with six equivalent Co(2)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-15°. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CoO6 octahedra that share corners with six equivalent Na(1)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with two equivalent Co(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-17°. In the second Co site, Co(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form CoO6 octahedra that share corners with six equivalent Na(2)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-15°. In the third Co site, Co(3) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form CoO6 octahedra that share edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), two equivalent Na(1), one Co(2), and two equivalent Co(1) atoms to form ONa3Co3 octahedra that share corners with six equivalent O(1)Na3Co3 octahedra, edges with four equivalent O(3)Na2Co3 square pyramids, and edges with eight equivalent O(2)Na2Co3 square pyramids. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded to one Na(1), one Na(2), one Co(1), one Co(2), and one Co(3) atom to form ONa2Co3 square pyramids that share corners with two equivalent O(3)Na2Co3 square pyramids, corners with seven equivalent O(2)Na2Co3 square pyramids, edges with four equivalent O(1)Na3Co3 octahedra, edges with two equivalent O(2)Na2Co3 square pyramids, and edges with two equivalent O(3)Na2Co3 square pyramids. In the third O site, O(3) is bonded to two equivalent Na(1), one Co(3), and two equivalent Co(1) atoms to form ONa2Co3 square pyramids that share corners with four equivalent O(2)Na2Co3 square pyramids, corners with five equivalent O(3)Na2Co3 square pyramids, edges with four equivalent O(1)Na3Co3 octahedra, and edges with four equivalent O(2)Na2Co3 square pyramids.
Na3(CoO2)4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted NaO6 octahedra that share corners with six equivalent Co(1)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with two equivalent Co(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-17°. Both Na(1)-O(1) bond lengths are 2.38 Å. Both Na(1)-O(2) bond lengths are 2.42 Å. Both Na(1)-O(3) bond lengths are 2.39 Å. In the second Na site, Na(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form distorted NaO6 octahedra that share corners with six equivalent Co(2)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-15°. Both Na(2)-O(1) bond lengths are 2.36 Å. All Na(2)-O(2) bond lengths are 2.41 Å. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CoO6 octahedra that share corners with six equivalent Na(1)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with two equivalent Co(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-17°. Both Co(1)-O(1) bond lengths are 2.06 Å. Both Co(1)-O(2) bond lengths are 1.99 Å. Both Co(1)-O(3) bond lengths are 2.08 Å. In the second Co site, Co(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form CoO6 octahedra that share corners with six equivalent Na(2)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-15°. Both Co(2)-O(1) bond lengths are 2.03 Å. All Co(2)-O(2) bond lengths are 2.04 Å. In the third Co site, Co(3) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form CoO6 octahedra that share edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. Both Co(3)-O(3) bond lengths are 1.87 Å. All Co(3)-O(2) bond lengths are 2.00 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), two equivalent Na(1), one Co(2), and two equivalent Co(1) atoms to form ONa3Co3 octahedra that share corners with six equivalent O(1)Na3Co3 octahedra, edges with four equivalent O(3)Na2Co3 square pyramids, and edges with eight equivalent O(2)Na2Co3 square pyramids. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded to one Na(1), one Na(2), one Co(1), one Co(2), and one Co(3) atom to form ONa2Co3 square pyramids that share corners with two equivalent O(3)Na2Co3 square pyramids, corners with seven equivalent O(2)Na2Co3 square pyramids, edges with four equivalent O(1)Na3Co3 octahedra, edges with two equivalent O(2)Na2Co3 square pyramids, and edges with two equivalent O(3)Na2Co3 square pyramids. In the third O site, O(3) is bonded to two equivalent Na(1), one Co(3), and two equivalent Co(1) atoms to form ONa2Co3 square pyramids that share corners with four equivalent O(2)Na2Co3 square pyramids, corners with five equivalent O(3)Na2Co3 square pyramids, edges with four equivalent O(1)Na3Co3 octahedra, and edges with four equivalent O(2)Na2Co3 square pyramids.