data_Na2C
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.78
_cell_length_b   4.78
_cell_length_c   6.73
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   132.41
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2C
_chemical_formula_sum   'Na4 C2'
_cell_volume   113.28
_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
  Na  Na2  1  0.93  0.97  0.87  1.0
  Na  Na3  1  0.93  0.03  0.23  1.0
  Na  Na4  1  0.93  0.41  0.48  1.0
  Na  Na5  1  0.93  0.59  0.12  1.0
  C  C0  1  0.93  0.55  0.26  1.0
  C  C1  1  0.93  0.45  0.62  1.0

data_Na2C
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.85
_cell_length_b   4.78
_cell_length_c   6.73
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   113.79
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2C
_chemical_formula_sum   'Na4 C2'
_cell_volume   113.28
_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
  Na  Na0  1  0.03  0.96  0.87  1.0
  Na  Na1  1  0.41  0.34  0.12  1.0
  Na  Na2  1  0.59  0.51  0.48  1.0
  Na  Na3  1  0.97  0.89  0.23  1.0
  C  C4  1  0.45  0.38  0.26  1.0
  C  C5  1  0.55  0.47  0.62  1.0

Na Na Na Na C C
Na Na Na Na C C 0 5 o + o 0 5 o o o 0 1 o + + 0 3 o o + 1 3 o o o 1 3 o - o 1 4 o o o 1 4 o - o 1 2 o o o 2 5 o o o 3 4 o o o 