data_CO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.54
_cell_length_b   3.54
_cell_length_c   2.63
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CO3
_chemical_formula_sum   'C1 O3'
_cell_volume   33.0
_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
  C  C0  1  0.0  0.0  0.0  1.0
  O  O1  1  0.77  0.77  0.32  1.0
  O  O2  1  0.77  0.0  0.32  1.0
  O  O3  1  0.0  0.77  0.32  1.0

data_CO3
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.01
_cell_length_b   5.01
_cell_length_c   2.63
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   CO3
_chemical_formula_sum   'C2 O6'
_cell_volume   65.99
_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
  C  C0  2  0.0  0.0  0.0  1.0
  O  O1  4  0.39  0.39  0.32  1.0
  O  O2  2  0.27  0.5  0.32  1.0

C O O O
C O O O 0 2 - o o 0 3 o - o 1 2 o + o 1 3 + o o 