The crystal structure described by Na2CoO3 crystallizes in the monoclinic Cm space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(2) atoms to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Co(1)O4 tetrahedra, corners with three equivalent Co(2)O4 tetrahedra, corners with five equivalent Na(1)O5 trigonal bipyramids,  an edgeedge with one Co(1)O4 tetrahedra, and edges with four equivalent Na(2)O5 trigonal bipyramids. In the second Na site, Na(2) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Co(2)O4 tetrahedra, corners with three equivalent Co(1)O4 tetrahedra, corners with five equivalent Na(2)O5 trigonal bipyramids,  an edgeedge with one Co(2)O4 tetrahedra, and edges with four equivalent Na(1)O5 trigonal bipyramids. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(3), one O(4), and two equivalent O(1) atoms to form CoO4 tetrahedra that share corners with two equivalent Co(2)O4 tetrahedra, corners with two equivalent Na(1)O5 trigonal bipyramids, corners with six equivalent Na(2)O5 trigonal bipyramids, and edges with two equivalent Na(1)O5 trigonal bipyramids. In the second Co site, Co(2) is bonded to one O(3), one O(4), and two equivalent O(2) atoms to form CoO4 tetrahedra that share corners with two equivalent Co(1)O4 tetrahedra, corners with two equivalent Na(2)O5 trigonal bipyramids, corners with six equivalent Na(1)O5 trigonal bipyramids, and edges with two equivalent Na(2)O5 trigonal bipyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(1), two equivalent Na(2), and one Co(1) atom to form distorted ONa4Co trigonal bipyramids that share  a cornercorner with one O(3)Na2Co2 tetrahedra, corners with three equivalent O(4)Na2Co2 tetrahedra, corners with five equivalent O(1)Na4Co trigonal bipyramids,  an edgeedge with one O(3)Na2Co2 tetrahedra, and edges with four equivalent O(2)Na4Co trigonal bipyramids. In the second O site, O(2) is bonded to two equivalent Na(1), two equivalent Na(2), and one Co(2) atom to form distorted ONa4Co trigonal bipyramids that share  a cornercorner with one O(4)Na2Co2 tetrahedra, corners with three equivalent O(3)Na2Co2 tetrahedra, corners with five equivalent O(2)Na4Co trigonal bipyramids,  an edgeedge with one O(4)Na2Co2 tetrahedra, and edges with four equivalent O(1)Na4Co trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Na(1), one Co(1), and one Co(2) atom to form distorted ONa2Co2 tetrahedra that share corners with two equivalent O(4)Na2Co2 tetrahedra, corners with two equivalent O(1)Na4Co trigonal bipyramids, corners with six equivalent O(2)Na4Co trigonal bipyramids, and edges with two equivalent O(1)Na4Co trigonal bipyramids. In the fourth O site, O(4) is bonded to two equivalent Na(2), one Co(1), and one Co(2) atom to form ONa2Co2 tetrahedra that share corners with two equivalent O(3)Na2Co2 tetrahedra, corners with two equivalent O(2)Na4Co trigonal bipyramids, corners with six equivalent O(1)Na4Co trigonal bipyramids, and edges with two equivalent O(2)Na4Co trigonal bipyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2CoO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.094
_cell_length_b   6.360
_cell_length_c   5.111
_cell_angle_alpha   89.518
_cell_angle_beta   88.993
_cell_angle_gamma   61.372
_symmetry_Int_Tables_number   1
_cell_volume   173.854
_cell_formula_units_Z   2
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  0.835  0.682  0.520  1.0
  Na  Na1  1  0.487  0.665  0.013  1.0
  Na  Na2  1  0.516  0.318  0.520  1.0
  Na  Na3  1  0.153  0.335  0.013  1.0
  Co  Co4  1  0.842  0.000  0.049  1.0
  Co  Co5  1  0.185  1.000  0.538  1.0
  O  O6  1  0.832  0.732  0.986  1.0
  O  O7  1  0.428  0.715  0.492  1.0
  O  O8  1  0.564  0.268  0.986  1.0
  O  O9  1  0.143  0.285  0.492  1.0
  O  O10  1  0.896  1.000  0.403  1.0
  O  O11  1  0.119  0.000  0.904  1.0
[/CIF]
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The crystal structure described by Na2CoO3 crystallizes in the monoclinic Cm space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(2) atoms to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Co(1)O4 tetrahedra, corners with three equivalent Co(2)O4 tetrahedra, corners with five equivalent Na(1)O5 trigonal bipyramids,  an edgeedge with one Co(1)O4 tetrahedra, and edges with four equivalent Na(2)O5 trigonal bipyramids. In the second Na site, Na(2) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Co(2)O4 tetrahedra, corners with three equivalent Co(1)O4 tetrahedra, corners with five equivalent Na(2)O5 trigonal bipyramids,  an edgeedge with one Co(2)O4 tetrahedra, and edges with four equivalent Na(1)O5 trigonal bipyramids. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(3), one O(4), and two equivalent O(1) atoms to form CoO4 tetrahedra that share corners with two equivalent Co(2)O4 tetrahedra, corners with two equivalent Na(1)O5 trigonal bipyramids, corners with six equivalent Na(2)O5 trigonal bipyramids, and edges with two equivalent Na(1)O5 trigonal bipyramids. In the second Co site, Co(2) is bonded to one O(3), one O(4), and two equivalent O(2) atoms to form CoO4 tetrahedra that share corners with two equivalent Co(1)O4 tetrahedra, corners with two equivalent Na(2)O5 trigonal bipyramids, corners with six equivalent Na(1)O5 trigonal bipyramids, and edges with two equivalent Na(2)O5 trigonal bipyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(1), two equivalent Na(2), and one Co(1) atom to form distorted ONa4Co trigonal bipyramids that share  a cornercorner with one O(3)Na2Co2 tetrahedra, corners with three equivalent O(4)Na2Co2 tetrahedra, corners with five equivalent O(1)Na4Co trigonal bipyramids,  an edgeedge with one O(3)Na2Co2 tetrahedra, and edges with four equivalent O(2)Na4Co trigonal bipyramids. In the second O site, O(2) is bonded to two equivalent Na(1), two equivalent Na(2), and one Co(2) atom to form distorted ONa4Co trigonal bipyramids that share  a cornercorner with one O(4)Na2Co2 tetrahedra, corners with three equivalent O(3)Na2Co2 tetrahedra, corners with five equivalent O(2)Na4Co trigonal bipyramids,  an edgeedge with one O(4)Na2Co2 tetrahedra, and edges with four equivalent O(1)Na4Co trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Na(1), one Co(1), and one Co(2) atom to form distorted ONa2Co2 tetrahedra that share corners with two equivalent O(4)Na2Co2 tetrahedra, corners with two equivalent O(1)Na4Co trigonal bipyramids, corners with six equivalent O(2)Na4Co trigonal bipyramids, and edges with two equivalent O(1)Na4Co trigonal bipyramids. In the fourth O site, O(4) is bonded to two equivalent Na(2), one Co(1), and one Co(2) atom to form ONa2Co2 tetrahedra that share corners with two equivalent O(3)Na2Co2 tetrahedra, corners with two equivalent O(2)Na4Co trigonal bipyramids, corners with six equivalent O(1)Na4Co trigonal bipyramids, and edges with two equivalent O(2)Na4Co trigonal bipyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2CoO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.094
_cell_length_b   6.360
_cell_length_c   5.111
_cell_angle_alpha   89.518
_cell_angle_beta   88.993
_cell_angle_gamma   61.372
_symmetry_Int_Tables_number   1
_cell_volume   173.854
_cell_formula_units_Z   2
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  0.835  0.682  0.520  1.0
  Na  Na1  1  0.487  0.665  0.013  1.0
  Na  Na2  1  0.516  0.318  0.520  1.0
  Na  Na3  1  0.153  0.335  0.013  1.0
  Co  Co4  1  0.842  0.000  0.049  1.0
  Co  Co5  1  0.185  1.000  0.538  1.0
  O  O6  1  0.832  0.732  0.986  1.0
  O  O7  1  0.428  0.715  0.492  1.0
  O  O8  1  0.564  0.268  0.986  1.0
  O  O9  1  0.143  0.285  0.492  1.0
  O  O10  1  0.896  1.000  0.403  1.0
  O  O11  1  0.119  0.000  0.904  1.0
[/CIF]
.