data_GaAs
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.67
_cell_length_b   5.67
_cell_length_c   5.52
_cell_angle_alpha   111.4
_cell_angle_beta   111.4
_cell_angle_gamma   29.94
_symmetry_Int_Tables_number   1
_chemical_formula_structural   GaAs
_chemical_formula_sum   'Ga2 As2'
_cell_volume   81.95
_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
  Ga  Ga2  1  0.37  0.0  0.36  1.0
  Ga  Ga3  1  0.49  0.0  0.76  1.0
  As  As0  1  0.62  0.0  0.85  1.0
  As  As1  1  0.24  0.0  0.26  1.0

data_GaAs
_symmetry_space_group_name_H-M   P-1
_cell_length_a   2.93
_cell_length_b   5.52
_cell_length_c   5.67
_cell_angle_alpha   111.4
_cell_angle_beta   104.97
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   2
_chemical_formula_structural   GaAs
_chemical_formula_sum   'Ga2 As2'
_cell_volume   81.95
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-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
  Ga  Ga0  2  0.0  0.3  0.94  1.0
  As  As1  2  0.0  0.21  0.81  1.0

Ga Ga As As
Ga Ga As As 0 3 o o o 1 2 o o o 