The structure described by Na2CoO3 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 5-coordinate geometry to two equivalent O(2) and three equivalent O(3) atoms. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to two equivalent O(1), two equivalent O(3), and three equivalent O(2) atoms. Co(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form corner-sharing CoO4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Na(2) and two equivalent Co(1) atoms. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Na(1), three equivalent Na(2), and one Co(1) atom. In the third O site, O(3) is bonded to two equivalent Na(2), three equivalent Na(1), and one Co(1) atom to form a mixture of distorted corner and edge-sharing ONa5Co octahedra. The corner-sharing octahedral tilt angles are 18°. is represented by the CIF card [CIF]
data_Na2CoO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.928
_cell_length_b   5.928
_cell_length_c   11.295
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   123.490
_symmetry_Int_Tables_number   1
_cell_volume   330.981
_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  0.964  0.036  0.145  1.0
  Na  Na1  1  0.634  0.366  0.079  1.0
  Na  Na2  1  0.866  0.134  0.579  1.0
  Na  Na3  1  0.536  0.464  0.645  1.0
  Na  Na4  1  0.464  0.536  0.355  1.0
  Na  Na5  1  0.134  0.866  0.421  1.0
  Na  Na6  1  0.036  0.964  0.855  1.0
  Na  Na7  1  0.366  0.634  0.921  1.0
  Co  Co8  1  0.755  0.245  0.341  1.0
  Co  Co9  1  0.745  0.255  0.841  1.0
  Co  Co10  1  0.255  0.745  0.159  1.0
  Co  Co11  1  0.245  0.755  0.659  1.0
  O  O12  1  0.443  0.057  0.250  1.0
  O  O13  1  0.663  0.337  0.471  1.0
  O  O14  1  0.921  0.079  0.361  1.0
  O  O15  1  0.837  0.163  0.971  1.0
  O  O16  1  0.579  0.421  0.861  1.0
  O  O17  1  0.943  0.557  0.250  1.0
  O  O18  1  0.057  0.443  0.750  1.0
  O  O19  1  0.163  0.837  0.029  1.0
  O  O20  1  0.079  0.921  0.639  1.0
  O  O21  1  0.421  0.579  0.139  1.0
  O  O22  1  0.337  0.663  0.529  1.0
  O  O23  1  0.557  0.943  0.750  1.0
[/CIF]
.
The structure described by Na2CoO3 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 5-coordinate geometry to two equivalent O(2) and three equivalent O(3) atoms. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to two equivalent O(1), two equivalent O(3), and three equivalent O(2) atoms. Co(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form corner-sharing CoO4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Na(2) and two equivalent Co(1) atoms. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Na(1), three equivalent Na(2), and one Co(1) atom. In the third O site, O(3) is bonded to two equivalent Na(2), three equivalent Na(1), and one Co(1) atom to form a mixture of distorted corner and edge-sharing ONa5Co octahedra. The corner-sharing octahedral tilt angles are 18°. is represented by the CIF card [CIF]
data_Na2CoO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.928
_cell_length_b   5.928
_cell_length_c   11.295
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   123.490
_symmetry_Int_Tables_number   1
_cell_volume   330.981
_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  0.964  0.036  0.145  1.0
  Na  Na1  1  0.634  0.366  0.079  1.0
  Na  Na2  1  0.866  0.134  0.579  1.0
  Na  Na3  1  0.536  0.464  0.645  1.0
  Na  Na4  1  0.464  0.536  0.355  1.0
  Na  Na5  1  0.134  0.866  0.421  1.0
  Na  Na6  1  0.036  0.964  0.855  1.0
  Na  Na7  1  0.366  0.634  0.921  1.0
  Co  Co8  1  0.755  0.245  0.341  1.0
  Co  Co9  1  0.745  0.255  0.841  1.0
  Co  Co10  1  0.255  0.745  0.159  1.0
  Co  Co11  1  0.245  0.755  0.659  1.0
  O  O12  1  0.443  0.057  0.250  1.0
  O  O13  1  0.663  0.337  0.471  1.0
  O  O14  1  0.921  0.079  0.361  1.0
  O  O15  1  0.837  0.163  0.971  1.0
  O  O16  1  0.579  0.421  0.861  1.0
  O  O17  1  0.943  0.557  0.250  1.0
  O  O18  1  0.057  0.443  0.750  1.0
  O  O19  1  0.163  0.837  0.029  1.0
  O  O20  1  0.079  0.921  0.639  1.0
  O  O21  1  0.421  0.579  0.139  1.0
  O  O22  1  0.337  0.663  0.529  1.0
  O  O23  1  0.557  0.943  0.750  1.0
[/CIF]
.