The compound described by Na2CoO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/c space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. In the second Na site, Na(2) 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 two equivalent Na(3)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, and edges with two equivalent Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 16-18°. In the third Na site, Na(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NaO6 octahedra that share corners with two equivalent Na(2)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with three equivalent Co(1)O6 octahedra, and edges with three equivalent Co(2)O6 octahedra. The corner-sharing octahedral tilt angles are 18°. There are two 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 two equivalent Na(2)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with three equivalent Na(3)O6 octahedra, and edges with three equivalent Co(2)O6 octahedra. The corner-sharing octahedral tilt angles are 16°. In the second Co site, Co(2) 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 two equivalent Na(2)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with three equivalent Na(3)O6 octahedra, and edges with three equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles are 18°. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), one Na(3), two equivalent Na(1), one Co(1), and one Co(2) atom to form a mixture of distorted corner and edge-sharing ONa4Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-11°. In the second O site, O(2) is bonded to one Na(2), one Na(3), two equivalent Na(1), one Co(1), and one Co(2) atom to form a mixture of distorted corner and edge-sharing ONa4Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-15°. In the third O site, O(3) is bonded to one Na(2), one Na(3), two equivalent Na(1), one Co(1), and one Co(2) atom to form a mixture of distorted corner and edge-sharing ONa4Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-17°. is represented by the CIF file [CIF]
data_Na2CoO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.340
_cell_length_b   5.340
_cell_length_c   10.932
_cell_angle_alpha   84.895
_cell_angle_beta   84.895
_cell_angle_gamma   120.389
_symmetry_Int_Tables_number   1
_cell_volume   264.582
_cell_formula_units_Z   4
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Na  Na0  1  0.842  0.684  1.000  1.0
  Na  Na1  1  0.000  0.500  0.500  1.0
  Na  Na2  1  0.914  0.086  0.750  1.0
  Na  Na3  1  0.500  0.000  0.000  1.0
  Na  Na4  1  0.316  0.158  0.500  1.0
  Na  Na5  1  0.684  0.842  0.500  1.0
  Na  Na6  1  0.086  0.914  0.250  1.0
  Na  Na7  1  0.158  0.316  0.000  1.0
  Co  Co8  1  0.748  0.252  0.250  1.0
  Co  Co9  1  0.584  0.416  0.750  1.0
  Co  Co10  1  0.416  0.584  0.250  1.0
  Co  Co11  1  0.252  0.748  0.750  1.0
  O  O12  1  0.942  0.737  0.649  1.0
  O  O13  1  0.676  0.488  0.349  1.0
  O  O14  1  0.879  0.437  0.850  1.0
  O  O15  1  0.512  0.324  0.151  1.0
  O  O16  1  0.737  0.942  0.149  1.0
  O  O17  1  0.437  0.879  0.350  1.0
  O  O18  1  0.563  0.121  0.650  1.0
  O  O19  1  0.263  0.058  0.851  1.0
  O  O20  1  0.488  0.676  0.849  1.0
  O  O21  1  0.121  0.563  0.150  1.0
  O  O22  1  0.324  0.512  0.651  1.0
  O  O23  1  0.058  0.263  0.351  1.0
[/CIF]
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The compound described by Na2CoO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/c space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. In the second Na site, Na(2) 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 two equivalent Na(3)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, and edges with two equivalent Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 16-18°. In the third Na site, Na(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NaO6 octahedra that share corners with two equivalent Na(2)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with three equivalent Co(1)O6 octahedra, and edges with three equivalent Co(2)O6 octahedra. The corner-sharing octahedral tilt angles are 18°. There are two 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 two equivalent Na(2)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with three equivalent Na(3)O6 octahedra, and edges with three equivalent Co(2)O6 octahedra. The corner-sharing octahedral tilt angles are 16°. In the second Co site, Co(2) 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 two equivalent Na(2)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with three equivalent Na(3)O6 octahedra, and edges with three equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles are 18°. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), one Na(3), two equivalent Na(1), one Co(1), and one Co(2) atom to form a mixture of distorted corner and edge-sharing ONa4Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-11°. In the second O site, O(2) is bonded to one Na(2), one Na(3), two equivalent Na(1), one Co(1), and one Co(2) atom to form a mixture of distorted corner and edge-sharing ONa4Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-15°. In the third O site, O(3) is bonded to one Na(2), one Na(3), two equivalent Na(1), one Co(1), and one Co(2) atom to form a mixture of distorted corner and edge-sharing ONa4Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-17°. is represented by the CIF file [CIF]
data_Na2CoO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.340
_cell_length_b   5.340
_cell_length_c   10.932
_cell_angle_alpha   84.895
_cell_angle_beta   84.895
_cell_angle_gamma   120.389
_symmetry_Int_Tables_number   1
_cell_volume   264.582
_cell_formula_units_Z   4
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Na  Na0  1  0.842  0.684  1.000  1.0
  Na  Na1  1  0.000  0.500  0.500  1.0
  Na  Na2  1  0.914  0.086  0.750  1.0
  Na  Na3  1  0.500  0.000  0.000  1.0
  Na  Na4  1  0.316  0.158  0.500  1.0
  Na  Na5  1  0.684  0.842  0.500  1.0
  Na  Na6  1  0.086  0.914  0.250  1.0
  Na  Na7  1  0.158  0.316  0.000  1.0
  Co  Co8  1  0.748  0.252  0.250  1.0
  Co  Co9  1  0.584  0.416  0.750  1.0
  Co  Co10  1  0.416  0.584  0.250  1.0
  Co  Co11  1  0.252  0.748  0.750  1.0
  O  O12  1  0.942  0.737  0.649  1.0
  O  O13  1  0.676  0.488  0.349  1.0
  O  O14  1  0.879  0.437  0.850  1.0
  O  O15  1  0.512  0.324  0.151  1.0
  O  O16  1  0.737  0.942  0.149  1.0
  O  O17  1  0.437  0.879  0.350  1.0
  O  O18  1  0.563  0.121  0.650  1.0
  O  O19  1  0.263  0.058  0.851  1.0
  O  O20  1  0.488  0.676  0.849  1.0
  O  O21  1  0.121  0.563  0.150  1.0
  O  O22  1  0.324  0.512  0.651  1.0
  O  O23  1  0.058  0.263  0.351  1.0
[/CIF]
.