data_Na2CuBr
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.15
_cell_length_b   5.15
_cell_length_c   3.6
_cell_angle_alpha   92.52
_cell_angle_beta   92.52
_cell_angle_gamma   90.98
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2CuBr
_chemical_formula_sum   'Na2 Cu1 Br1'
_cell_volume   95.1
_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
  Na  Na2  1  0.69  0.83  0.8  1.0
  Na  Na3  1  0.69  0.17  0.8  1.0
  Cu  Cu1  1  0.0  0.0  0.0  1.0
  Br  Br0  1  0.61  0.0  0.0  1.0

data_Na2CuBr
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.6
_cell_length_b   5.15
_cell_length_c   5.15
_cell_angle_alpha   90.98
_cell_angle_beta   92.52
_cell_angle_gamma   92.52
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2CuBr
_chemical_formula_sum   'Na2 Cu1 Br1'
_cell_volume   95.1
_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
  Na  Na0  1  0.8  0.69  0.17  1.0
  Na  Na1  1  0.8  0.69  0.83  1.0
  Cu  Cu2  1  0.0  0.0  0.0  1.0
  Br  Br3  1  0.0  0.61  0.0  1.0

Na Na Cu Br
Na Na Cu Br 0 3 o + + 0 2 + + + 1 3 o o + 1 2 + o + 2 3 - o o 