data_Ba2Nb5O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.2
_cell_length_b   4.2
_cell_length_c   12.27
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ba2Nb5O9
_chemical_formula_sum   'Ba2 Nb5 O9'
_cell_volume   216.15
_cell_formula_units_Z   1
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  0.0  0.0  0.08  1.0
  Ba  Ba1  1  0.0  0.0  0.2  1.0
  Nb  Nb2  1  0.1  0.0  0.0  1.0
  Nb  Nb3  1  0.0  0.1  0.0  1.0
  Nb  Nb4  1  0.1  0.1  0.0  1.0
  Nb  Nb5  1  0.1  0.1  0.14  1.0
  Nb  Nb6  1  0.1  0.1  0.27  1.0
  O  O7  1  0.0  0.0  0.0  1.0
  O  O8  1  0.1  0.0  0.13  1.0
  O  O9  1  0.0  0.1  0.13  1.0
  O  O10  1  0.1  0.1  0.15  1.0
  O  O11  1  0.1  0.0  0.14  1.0
  O  O12  1  0.0  0.1  0.14  1.0
  O  O13  1  0.1  0.1  0.13  1.0
  O  O14  1  0.1  0.0  0.15  1.0
  O  O15  1  0.0  0.1  0.15  1.0

data_Ba2Nb5O9
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.93
_cell_length_b   5.93
_cell_length_c   12.27
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Ba2Nb5O9
_chemical_formula_sum   'Ba4 Nb10 O18'
_cell_volume   432.31
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  2  0.0  0.0  0.08  1.0
  Ba  Ba1  2  0.0  0.0  0.2  1.0
  Nb  Nb2  4  0.05  0.05  -0.0  1.0
  Nb  Nb3  2  0.1  0.0  0.0  1.0
  Nb  Nb4  2  0.1  0.0  0.14  1.0
  Nb  Nb5  2  0.1  0.0  0.27  1.0
  O  O6  4  0.05  0.05  0.13  1.0
  O  O7  4  0.05  0.05  0.14  1.0
  O  O8  4  0.05  0.05  0.15  1.0
  O  O9  2  0.0  0.0  0.0  1.0
  O  O10  2  0.1  0.0  0.13  1.0
  O  O11  2  0.1  0.0  0.15  1.0

Ba Ba Nb Nb Nb Nb Nb O O O O O O O O O