data_Na2C
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.86
_cell_length_b   6.86
_cell_length_c   3.5
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   141.08
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2C
_chemical_formula_sum   'Na4 C2'
_cell_volume   103.33
_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  0.0  0.0  0.0  1.0
  Na  Na3  1  0.29  0.0  0.75  1.0
  Na  Na4  1  0.29  0.11  0.75  1.0
  Na  Na5  1  0.29  0.89  0.75  1.0
  C  C0  1  0.29  0.22  0.0  1.0
  C  C1  1  0.29  0.78  0.0  1.0

data_Na2C
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.5
_cell_length_b   4.57
_cell_length_c   6.86
_cell_angle_alpha   109.46
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2C
_chemical_formula_sum   'Na4 C2'
_cell_volume   103.33
_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  0.0  0.0  0.0  1.0
  Na  Na1  1  0.75  0.0  0.29  1.0
  Na  Na2  1  0.75  0.11  0.4  1.0
  Na  Na3  1  0.75  0.89  0.17  1.0
  C  C4  1  -0.0  0.78  0.06  1.0
  C  C5  1  0.0  0.22  0.51  1.0

Na Na Na Na C C