The crystal structure described by Na2BaO2 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a trigonal non-coplanar geometry to one O(1) and two equivalent O(2) atoms. In the second Na site, Na(2) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form NaO4 tetrahedra that share corners with four equivalent Na(2)O4 tetrahedra, corners with four equivalent Ba(1)O5 trigonal bipyramids, and edges with three equivalent Ba(1)O5 trigonal bipyramids. Ba(1) is bonded to two equivalent O(2) and three equivalent O(1) atoms to form distorted BaO5 trigonal bipyramids that share corners with four equivalent Na(2)O4 tetrahedra, corners with four equivalent Ba(1)O5 trigonal bipyramids, edges with three equivalent Na(2)O4 tetrahedra, and edges with two equivalent Ba(1)O5 trigonal bipyramids. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), two equivalent Na(2), and three equivalent Ba(1) atoms to form distorted OBa3Na3 octahedra that share corners with two equivalent O(2)Ba2Na4 octahedra, corners with four equivalent O(1)Ba3Na3 octahedra, edges with two equivalent O(1)Ba3Na3 octahedra, and edges with five equivalent O(2)Ba2Na4 octahedra. The corner-sharing octahedral tilt angles range from 26-63°. In the second O site, O(2) is bonded to two equivalent Na(1), two equivalent Na(2), and two equivalent Ba(1) atoms to form distorted OBa2Na4 octahedra that share corners with two equivalent O(2)Ba2Na4 octahedra, corners with two equivalent O(1)Ba3Na3 octahedra, edges with two equivalent O(2)Ba2Na4 octahedra, and edges with five equivalent O(1)Ba3Na3 octahedra. The corner-sharing octahedral tilt angles range from 26-54°. is represented by the CIF file [CIF]
data_BaNa2O2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.870
_cell_length_b   6.870
_cell_length_c   7.873
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   147.847
_symmetry_Int_Tables_number   1
_cell_volume   197.765
_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
  Ba  Ba0  1  0.807  0.193  0.067  1.0
  Ba  Ba1  1  0.193  0.807  0.567  1.0
  Na  Na2  1  0.944  0.056  0.610  1.0
  Na  Na3  1  0.576  0.424  0.857  1.0
  Na  Na4  1  0.056  0.944  0.110  1.0
  Na  Na5  1  0.424  0.576  0.357  1.0
  O  O6  1  0.812  0.188  0.411  1.0
  O  O7  1  0.544  0.456  0.570  1.0
  O  O8  1  0.456  0.544  0.070  1.0
  O  O9  1  0.188  0.812  0.911  1.0
[/CIF]
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The crystal structure described by Na2BaO2 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a trigonal non-coplanar geometry to one O(1) and two equivalent O(2) atoms. In the second Na site, Na(2) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form NaO4 tetrahedra that share corners with four equivalent Na(2)O4 tetrahedra, corners with four equivalent Ba(1)O5 trigonal bipyramids, and edges with three equivalent Ba(1)O5 trigonal bipyramids. Ba(1) is bonded to two equivalent O(2) and three equivalent O(1) atoms to form distorted BaO5 trigonal bipyramids that share corners with four equivalent Na(2)O4 tetrahedra, corners with four equivalent Ba(1)O5 trigonal bipyramids, edges with three equivalent Na(2)O4 tetrahedra, and edges with two equivalent Ba(1)O5 trigonal bipyramids. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), two equivalent Na(2), and three equivalent Ba(1) atoms to form distorted OBa3Na3 octahedra that share corners with two equivalent O(2)Ba2Na4 octahedra, corners with four equivalent O(1)Ba3Na3 octahedra, edges with two equivalent O(1)Ba3Na3 octahedra, and edges with five equivalent O(2)Ba2Na4 octahedra. The corner-sharing octahedral tilt angles range from 26-63°. In the second O site, O(2) is bonded to two equivalent Na(1), two equivalent Na(2), and two equivalent Ba(1) atoms to form distorted OBa2Na4 octahedra that share corners with two equivalent O(2)Ba2Na4 octahedra, corners with two equivalent O(1)Ba3Na3 octahedra, edges with two equivalent O(2)Ba2Na4 octahedra, and edges with five equivalent O(1)Ba3Na3 octahedra. The corner-sharing octahedral tilt angles range from 26-54°. is represented by the CIF file [CIF]
data_BaNa2O2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.870
_cell_length_b   6.870
_cell_length_c   7.873
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   147.847
_symmetry_Int_Tables_number   1
_cell_volume   197.765
_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
  Ba  Ba0  1  0.807  0.193  0.067  1.0
  Ba  Ba1  1  0.193  0.807  0.567  1.0
  Na  Na2  1  0.944  0.056  0.610  1.0
  Na  Na3  1  0.576  0.424  0.857  1.0
  Na  Na4  1  0.056  0.944  0.110  1.0
  Na  Na5  1  0.424  0.576  0.357  1.0
  O  O6  1  0.812  0.188  0.411  1.0
  O  O7  1  0.544  0.456  0.570  1.0
  O  O8  1  0.456  0.544  0.070  1.0
  O  O9  1  0.188  0.812  0.911  1.0
[/CIF]
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