The structure described by Na2CoO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2 space group. There are five inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted NaO6 octahedra that share  a cornercorner with one Na(2)O6 octahedra,  a cornercorner with one Na(3)O6 octahedra,  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Co(1)O6 octahedra,  an edgeedge with one Co(2)O6 octahedra,  an edgeedge with one Co(3)O6 octahedra,  an edgeedge with one Co(4)O6 octahedra, edges with three equivalent Na(4)O6 octahedra, and edges with three equivalent Na(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-19°. In the second Na site, Na(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(4)O6 octahedra, corners with two equivalent Na(5)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with two equivalent Na(5)O6 octahedra, edges with three equivalent Co(3)O6 octahedra, and edges with three equivalent Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 18-19°. In the third Na site, Na(3) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms to form NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(4)O6 octahedra, corners with two equivalent Na(5)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with two equivalent Na(5)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 range from 18-19°. In the fourth Na site, Na(4) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted NaO6 octahedra that share  a cornercorner with one Na(2)O6 octahedra,  a cornercorner with one Na(3)O6 octahedra,  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Co(1)O6 octahedra,  an edgeedge with one Co(2)O6 octahedra,  an edgeedge with one Co(3)O6 octahedra,  an edgeedge with one Co(4)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, and edges with three equivalent Na(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-18°. In the fifth Na site, Na(5) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted NaO6 octahedra that share  a cornercorner with one Na(2)O6 octahedra,  a cornercorner with one Na(3)O6 octahedra,  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Co(1)O6 octahedra,  an edgeedge with one Co(2)O6 octahedra,  an edgeedge with one Co(3)O6 octahedra,  an edgeedge with one Co(4)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, and edges with three equivalent Na(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-19°. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms to form CoO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(4)O6 octahedra, corners with two equivalent Na(5)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with two equivalent Na(5)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 range from 14-16°. In the second Co site, Co(2) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms to form CoO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(4)O6 octahedra, corners with two equivalent Na(5)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with two equivalent Na(5)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 range from 14-16°. In the third Co site, Co(3) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form CoO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(4)O6 octahedra, corners with two equivalent Na(5)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with two equivalent Na(5)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, and edges with three equivalent Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-12°. In the fourth Co site, Co(4) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form CoO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(4)O6 octahedra, corners with two equivalent Na(5)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with two equivalent Na(5)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, and edges with three equivalent Co(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 17-18°. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(3), one Na(4), one Na(5), 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 0-14°. In the second O site, O(2) is bonded to one Na(1), one Na(2), one Na(4), one Na(5), one Co(3), and one Co(4) atom to form a mixture of distorted corner and edge-sharing ONa4Co2 octahedra. The corner-sharing octahedral tilt angles range from 1-15°. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Na(4), one Na(5), one Co(3), and one Co(4) atom to form a mixture of distorted corner and edge-sharing ONa4Co2 octahedra. The corner-sharing octahedral tilt angles range from 1-15°. In the fourth O site, O(4) is bonded to one Na(1), one Na(3), one Na(4), one Na(5), 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 fifth O site, O(5) is bonded to one Na(1), one Na(2), one Na(4), one Na(5), one Co(3), and one Co(4) atom to form a mixture of distorted corner and edge-sharing ONa4Co2 octahedra. The corner-sharing octahedral tilt angles range from 2-15°. In the sixth O site, O(6) is bonded to one Na(1), one Na(3), one Na(4), one Na(5), 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 0-14°. is represented by the CIF card [CIF]
data_Na2CoO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.281
_cell_length_b   5.281
_cell_length_c   10.893
_cell_angle_alpha   94.173
_cell_angle_beta   85.831
_cell_angle_gamma   60.082
_symmetry_Int_Tables_number   1
_cell_volume   260.560
_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  0.251  0.751  0.252  1.0
  Na  Na1  1  0.751  0.251  0.748  1.0
  Na  Na2  1  0.000  0.000  0.000  1.0
  Na  Na3  1  0.500  0.500  0.500  1.0
  Na  Na4  1  0.907  0.409  0.252  1.0
  Na  Na5  1  0.409  0.907  0.748  1.0
  Na  Na6  1  0.593  0.091  0.251  1.0
  Na  Na7  1  0.091  0.593  0.749  1.0
  Co  Co8  1  0.171  0.171  0.500  1.0
  Co  Co9  1  0.829  0.829  0.500  1.0
  Co  Co10  1  0.669  0.669  0.000  1.0
  Co  Co11  1  0.332  0.332  1.000  1.0
  O  O12  1  0.913  0.088  0.402  1.0
  O  O13  1  0.419  0.595  0.899  1.0
  O  O14  1  0.595  0.419  0.101  1.0
  O  O15  1  0.088  0.913  0.598  1.0
  O  O16  1  0.947  0.662  0.101  1.0
  O  O17  1  0.461  0.153  0.598  1.0
  O  O18  1  0.357  0.017  0.100  1.0
  O  O19  1  0.847  0.539  0.597  1.0
  O  O20  1  0.539  0.847  0.403  1.0
  O  O21  1  0.017  0.357  0.900  1.0
  O  O22  1  0.153  0.461  0.402  1.0
  O  O23  1  0.662  0.947  0.899  1.0
[/CIF]
.
The structure described by Na2CoO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2 space group. There are five inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted NaO6 octahedra that share  a cornercorner with one Na(2)O6 octahedra,  a cornercorner with one Na(3)O6 octahedra,  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Co(1)O6 octahedra,  an edgeedge with one Co(2)O6 octahedra,  an edgeedge with one Co(3)O6 octahedra,  an edgeedge with one Co(4)O6 octahedra, edges with three equivalent Na(4)O6 octahedra, and edges with three equivalent Na(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-19°. In the second Na site, Na(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(4)O6 octahedra, corners with two equivalent Na(5)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with two equivalent Na(5)O6 octahedra, edges with three equivalent Co(3)O6 octahedra, and edges with three equivalent Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 18-19°. In the third Na site, Na(3) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms to form NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(4)O6 octahedra, corners with two equivalent Na(5)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with two equivalent Na(5)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 range from 18-19°. In the fourth Na site, Na(4) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted NaO6 octahedra that share  a cornercorner with one Na(2)O6 octahedra,  a cornercorner with one Na(3)O6 octahedra,  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Co(1)O6 octahedra,  an edgeedge with one Co(2)O6 octahedra,  an edgeedge with one Co(3)O6 octahedra,  an edgeedge with one Co(4)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, and edges with three equivalent Na(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-18°. In the fifth Na site, Na(5) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted NaO6 octahedra that share  a cornercorner with one Na(2)O6 octahedra,  a cornercorner with one Na(3)O6 octahedra,  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Co(1)O6 octahedra,  an edgeedge with one Co(2)O6 octahedra,  an edgeedge with one Co(3)O6 octahedra,  an edgeedge with one Co(4)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, and edges with three equivalent Na(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-19°. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms to form CoO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(4)O6 octahedra, corners with two equivalent Na(5)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with two equivalent Na(5)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 range from 14-16°. In the second Co site, Co(2) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms to form CoO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(4)O6 octahedra, corners with two equivalent Na(5)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with two equivalent Na(5)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 range from 14-16°. In the third Co site, Co(3) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form CoO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(4)O6 octahedra, corners with two equivalent Na(5)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with two equivalent Na(5)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, and edges with three equivalent Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-12°. In the fourth Co site, Co(4) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form CoO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(4)O6 octahedra, corners with two equivalent Na(5)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with two equivalent Na(5)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, and edges with three equivalent Co(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 17-18°. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(3), one Na(4), one Na(5), 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 0-14°. In the second O site, O(2) is bonded to one Na(1), one Na(2), one Na(4), one Na(5), one Co(3), and one Co(4) atom to form a mixture of distorted corner and edge-sharing ONa4Co2 octahedra. The corner-sharing octahedral tilt angles range from 1-15°. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Na(4), one Na(5), one Co(3), and one Co(4) atom to form a mixture of distorted corner and edge-sharing ONa4Co2 octahedra. The corner-sharing octahedral tilt angles range from 1-15°. In the fourth O site, O(4) is bonded to one Na(1), one Na(3), one Na(4), one Na(5), 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 fifth O site, O(5) is bonded to one Na(1), one Na(2), one Na(4), one Na(5), one Co(3), and one Co(4) atom to form a mixture of distorted corner and edge-sharing ONa4Co2 octahedra. The corner-sharing octahedral tilt angles range from 2-15°. In the sixth O site, O(6) is bonded to one Na(1), one Na(3), one Na(4), one Na(5), 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 0-14°. is represented by the CIF card [CIF]
data_Na2CoO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.281
_cell_length_b   5.281
_cell_length_c   10.893
_cell_angle_alpha   94.173
_cell_angle_beta   85.831
_cell_angle_gamma   60.082
_symmetry_Int_Tables_number   1
_cell_volume   260.560
_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  0.251  0.751  0.252  1.0
  Na  Na1  1  0.751  0.251  0.748  1.0
  Na  Na2  1  0.000  0.000  0.000  1.0
  Na  Na3  1  0.500  0.500  0.500  1.0
  Na  Na4  1  0.907  0.409  0.252  1.0
  Na  Na5  1  0.409  0.907  0.748  1.0
  Na  Na6  1  0.593  0.091  0.251  1.0
  Na  Na7  1  0.091  0.593  0.749  1.0
  Co  Co8  1  0.171  0.171  0.500  1.0
  Co  Co9  1  0.829  0.829  0.500  1.0
  Co  Co10  1  0.669  0.669  0.000  1.0
  Co  Co11  1  0.332  0.332  1.000  1.0
  O  O12  1  0.913  0.088  0.402  1.0
  O  O13  1  0.419  0.595  0.899  1.0
  O  O14  1  0.595  0.419  0.101  1.0
  O  O15  1  0.088  0.913  0.598  1.0
  O  O16  1  0.947  0.662  0.101  1.0
  O  O17  1  0.461  0.153  0.598  1.0
  O  O18  1  0.357  0.017  0.100  1.0
  O  O19  1  0.847  0.539  0.597  1.0
  O  O20  1  0.539  0.847  0.403  1.0
  O  O21  1  0.017  0.357  0.900  1.0
  O  O22  1  0.153  0.461  0.402  1.0
  O  O23  1  0.662  0.947  0.899  1.0
[/CIF]
.