The structure described by Na2BaO2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted trigonal planar geometry to three equivalent O(1) atoms. In the second Na site, Na(2) is bonded to one O(1) and three equivalent O(2) atoms to form a mixture of distorted edge and corner-sharing NaO4 tetrahedra. Ba(1) is bonded in a rectangular see-saw-like geometry to one O(1) and three equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), three equivalent Na(1), and one Ba(1) atom to form distorted OBaNa4 trigonal bipyramids that share corners with four equivalent O(2)Ba3Na3 octahedra, corners with four equivalent O(1)BaNa4 trigonal bipyramids,  an edgeedge with one O(2)Ba3Na3 octahedra, and  an edgeedge with one O(1)BaNa4 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 27-67°. In the second O site, O(2) is bonded to three equivalent Na(2) and three equivalent Ba(1) atoms to form distorted OBa3Na3 octahedra that share corners with four equivalent O(1)BaNa4 trigonal bipyramids, edges with six equivalent O(2)Ba3Na3 octahedra, and  an edgeedge with one O(1)BaNa4 trigonal bipyramid. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaNa2O2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.973
_cell_length_b   6.672
_cell_length_c   8.421
_cell_angle_alpha   81.863
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   387.866
_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
  Ba  Ba0  1  0.408  0.092  0.697  1.0
  Ba  Ba1  1  0.092  0.592  0.697  1.0
  Ba  Ba2  1  0.908  0.408  0.303  1.0
  Ba  Ba3  1  0.592  0.908  0.303  1.0
  Na  Na4  1  0.358  0.353  0.052  1.0
  Na  Na5  1  0.142  0.853  0.052  1.0
  Na  Na6  1  0.867  0.042  0.621  1.0
  Na  Na7  1  0.633  0.542  0.621  1.0
  Na  Na8  1  0.367  0.458  0.379  1.0
  Na  Na9  1  0.133  0.958  0.379  1.0
  Na  Na10  1  0.858  0.147  0.948  1.0
  Na  Na11  1  0.642  0.647  0.948  1.0
  O  O12  1  0.595  0.333  0.863  1.0
  O  O13  1  0.905  0.833  0.863  1.0
  O  O14  1  0.121  0.266  0.544  1.0
  O  O15  1  0.379  0.766  0.544  1.0
  O  O16  1  0.621  0.234  0.456  1.0
  O  O17  1  0.879  0.734  0.456  1.0
  O  O18  1  0.095  0.167  0.137  1.0
  O  O19  1  0.405  0.667  0.137  1.0
[/CIF]
.
The structure described by Na2BaO2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted trigonal planar geometry to three equivalent O(1) atoms. In the second Na site, Na(2) is bonded to one O(1) and three equivalent O(2) atoms to form a mixture of distorted edge and corner-sharing NaO4 tetrahedra. Ba(1) is bonded in a rectangular see-saw-like geometry to one O(1) and three equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), three equivalent Na(1), and one Ba(1) atom to form distorted OBaNa4 trigonal bipyramids that share corners with four equivalent O(2)Ba3Na3 octahedra, corners with four equivalent O(1)BaNa4 trigonal bipyramids,  an edgeedge with one O(2)Ba3Na3 octahedra, and  an edgeedge with one O(1)BaNa4 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 27-67°. In the second O site, O(2) is bonded to three equivalent Na(2) and three equivalent Ba(1) atoms to form distorted OBa3Na3 octahedra that share corners with four equivalent O(1)BaNa4 trigonal bipyramids, edges with six equivalent O(2)Ba3Na3 octahedra, and  an edgeedge with one O(1)BaNa4 trigonal bipyramid. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaNa2O2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.973
_cell_length_b   6.672
_cell_length_c   8.421
_cell_angle_alpha   81.863
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   387.866
_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
  Ba  Ba0  1  0.408  0.092  0.697  1.0
  Ba  Ba1  1  0.092  0.592  0.697  1.0
  Ba  Ba2  1  0.908  0.408  0.303  1.0
  Ba  Ba3  1  0.592  0.908  0.303  1.0
  Na  Na4  1  0.358  0.353  0.052  1.0
  Na  Na5  1  0.142  0.853  0.052  1.0
  Na  Na6  1  0.867  0.042  0.621  1.0
  Na  Na7  1  0.633  0.542  0.621  1.0
  Na  Na8  1  0.367  0.458  0.379  1.0
  Na  Na9  1  0.133  0.958  0.379  1.0
  Na  Na10  1  0.858  0.147  0.948  1.0
  Na  Na11  1  0.642  0.647  0.948  1.0
  O  O12  1  0.595  0.333  0.863  1.0
  O  O13  1  0.905  0.833  0.863  1.0
  O  O14  1  0.121  0.266  0.544  1.0
  O  O15  1  0.379  0.766  0.544  1.0
  O  O16  1  0.621  0.234  0.456  1.0
  O  O17  1  0.879  0.734  0.456  1.0
  O  O18  1  0.095  0.167  0.137  1.0
  O  O19  1  0.405  0.667  0.137  1.0
[/CIF]
.