The structure described by BaO2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 11-coordinate geometry to two equivalent O(1), three equivalent O(2), three equivalent O(3), and three equivalent O(4) atoms. In the second Ba site, Ba(2) is bonded in a 11-coordinate geometry to two equivalent O(2), three equivalent O(1), three equivalent O(3), and three equivalent O(4) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ba(1) and three equivalent Ba(2) atoms to form OBa5 trigonal bipyramids that share corners with six equivalent O(4)Ba6 octahedra, corners with four equivalent O(1)Ba5 trigonal bipyramids, corners with four equivalent O(2)Ba5 trigonal bipyramids, edges with two equivalent O(1)Ba5 trigonal bipyramids, edges with four equivalent O(2)Ba5 trigonal bipyramids, and faces with three equivalent O(4)Ba6 octahedra. The corner-sharing octahedral tilt angles range from 24-65°. In the second O site, O(2) is bonded to two equivalent Ba(2) and three equivalent Ba(1) atoms to form OBa5 trigonal bipyramids that share corners with six equivalent O(4)Ba6 octahedra, corners with four equivalent O(1)Ba5 trigonal bipyramids, corners with four equivalent O(2)Ba5 trigonal bipyramids, edges with two equivalent O(2)Ba5 trigonal bipyramids, edges with four equivalent O(1)Ba5 trigonal bipyramids, and faces with three equivalent O(4)Ba6 octahedra. The corner-sharing octahedral tilt angles range from 23-69°. In the third O site, O(3) is bonded in a 6-coordinate geometry to three equivalent Ba(1) and three equivalent Ba(2) atoms. In the fourth O site, O(4) is bonded to three equivalent Ba(1) and three equivalent Ba(2) atoms to form distorted OBa6 octahedra that share corners with eight equivalent O(4)Ba6 octahedra, corners with six equivalent O(1)Ba5 trigonal bipyramids, corners with six equivalent O(2)Ba5 trigonal bipyramids, edges with two equivalent O(4)Ba6 octahedra, faces with three equivalent O(1)Ba5 trigonal bipyramids, and faces with three equivalent O(2)Ba5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 41-63°. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.825
_cell_length_b   7.684
_cell_length_c   11.128
_cell_angle_alpha   90.000
_cell_angle_beta   121.170
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   426.183
_cell_formula_units_Z   8
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  0.138  0.888  0.888  1.0
  Ba  Ba1  1  0.138  0.612  0.388  1.0
  Ba  Ba2  1  0.862  0.112  0.112  1.0
  Ba  Ba3  1  0.862  0.388  0.612  1.0
  Ba  Ba4  1  0.612  0.943  0.362  1.0
  Ba  Ba5  1  0.612  0.557  0.862  1.0
  Ba  Ba6  1  0.388  0.057  0.638  1.0
  Ba  Ba7  1  0.388  0.443  0.138  1.0
  O  O8  1  0.873  0.023  0.632  1.0
  O  O9  1  0.873  0.477  0.132  1.0
  O  O10  1  0.127  0.977  0.368  1.0
  O  O11  1  0.127  0.523  0.868  1.0
  O  O12  1  0.366  0.100  0.114  1.0
  O  O13  1  0.366  0.400  0.614  1.0
  O  O14  1  0.634  0.900  0.886  1.0
  O  O15  1  0.634  0.600  0.386  1.0
  O  O16  1  0.943  0.268  0.893  1.0
  O  O17  1  0.943  0.232  0.393  1.0
  O  O18  1  0.057  0.732  0.107  1.0
  O  O19  1  0.057  0.768  0.607  1.0
  O  O20  1  0.344  0.239  0.391  1.0
  O  O21  1  0.344  0.261  0.891  1.0
  O  O22  1  0.656  0.761  0.609  1.0
  O  O23  1  0.656  0.739  0.109  1.0
[/CIF]
.
The structure described by BaO2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 11-coordinate geometry to two equivalent O(1), three equivalent O(2), three equivalent O(3), and three equivalent O(4) atoms. In the second Ba site, Ba(2) is bonded in a 11-coordinate geometry to two equivalent O(2), three equivalent O(1), three equivalent O(3), and three equivalent O(4) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ba(1) and three equivalent Ba(2) atoms to form OBa5 trigonal bipyramids that share corners with six equivalent O(4)Ba6 octahedra, corners with four equivalent O(1)Ba5 trigonal bipyramids, corners with four equivalent O(2)Ba5 trigonal bipyramids, edges with two equivalent O(1)Ba5 trigonal bipyramids, edges with four equivalent O(2)Ba5 trigonal bipyramids, and faces with three equivalent O(4)Ba6 octahedra. The corner-sharing octahedral tilt angles range from 24-65°. In the second O site, O(2) is bonded to two equivalent Ba(2) and three equivalent Ba(1) atoms to form OBa5 trigonal bipyramids that share corners with six equivalent O(4)Ba6 octahedra, corners with four equivalent O(1)Ba5 trigonal bipyramids, corners with four equivalent O(2)Ba5 trigonal bipyramids, edges with two equivalent O(2)Ba5 trigonal bipyramids, edges with four equivalent O(1)Ba5 trigonal bipyramids, and faces with three equivalent O(4)Ba6 octahedra. The corner-sharing octahedral tilt angles range from 23-69°. In the third O site, O(3) is bonded in a 6-coordinate geometry to three equivalent Ba(1) and three equivalent Ba(2) atoms. In the fourth O site, O(4) is bonded to three equivalent Ba(1) and three equivalent Ba(2) atoms to form distorted OBa6 octahedra that share corners with eight equivalent O(4)Ba6 octahedra, corners with six equivalent O(1)Ba5 trigonal bipyramids, corners with six equivalent O(2)Ba5 trigonal bipyramids, edges with two equivalent O(4)Ba6 octahedra, faces with three equivalent O(1)Ba5 trigonal bipyramids, and faces with three equivalent O(2)Ba5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 41-63°. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.825
_cell_length_b   7.684
_cell_length_c   11.128
_cell_angle_alpha   90.000
_cell_angle_beta   121.170
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   426.183
_cell_formula_units_Z   8
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  0.138  0.888  0.888  1.0
  Ba  Ba1  1  0.138  0.612  0.388  1.0
  Ba  Ba2  1  0.862  0.112  0.112  1.0
  Ba  Ba3  1  0.862  0.388  0.612  1.0
  Ba  Ba4  1  0.612  0.943  0.362  1.0
  Ba  Ba5  1  0.612  0.557  0.862  1.0
  Ba  Ba6  1  0.388  0.057  0.638  1.0
  Ba  Ba7  1  0.388  0.443  0.138  1.0
  O  O8  1  0.873  0.023  0.632  1.0
  O  O9  1  0.873  0.477  0.132  1.0
  O  O10  1  0.127  0.977  0.368  1.0
  O  O11  1  0.127  0.523  0.868  1.0
  O  O12  1  0.366  0.100  0.114  1.0
  O  O13  1  0.366  0.400  0.614  1.0
  O  O14  1  0.634  0.900  0.886  1.0
  O  O15  1  0.634  0.600  0.386  1.0
  O  O16  1  0.943  0.268  0.893  1.0
  O  O17  1  0.943  0.232  0.393  1.0
  O  O18  1  0.057  0.732  0.107  1.0
  O  O19  1  0.057  0.768  0.607  1.0
  O  O20  1  0.344  0.239  0.391  1.0
  O  O21  1  0.344  0.261  0.891  1.0
  O  O22  1  0.656  0.761  0.609  1.0
  O  O23  1  0.656  0.739  0.109  1.0
[/CIF]
.