data_Na3C
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.35
_cell_length_b   8.35
_cell_length_c   8.35
_cell_angle_alpha   149.71
_cell_angle_beta   149.71
_cell_angle_gamma   43.37
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na3C
_chemical_formula_sum   'Na6 C2'
_cell_volume   147.78
_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  0.18  0.0  1.0
  Na  Na3  1  0.18  0.0  0.0  1.0
  Na  Na4  1  0.18  0.0  0.88  1.0
  Na  Na5  1  0.0  0.18  0.88  1.0
  Na  Na6  1  0.0  0.0  0.46  1.0
  Na  Na7  1  0.0  0.0  0.07  1.0
  C  C0  1  0.0  0.0  0.88  1.0
  C  C1  1  0.0  0.0  0.64  1.0

data_Na3C
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.17
_cell_length_b   6.17
_cell_length_c   8.35
_cell_angle_alpha   90.0
_cell_angle_beta   111.68
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Na3C
_chemical_formula_sum   'Na12 C4'
_cell_volume   295.56
_cell_formula_units_Z   4
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
  Na  Na0  4  0.29  0.41  0.7  1.0
  Na  Na1  4  0.41  0.41  0.82  1.0
  Na  Na2  2  0.07  0.0  0.07  1.0
  Na  Na3  2  0.46  0.0  0.46  1.0
  C  C4  2  0.14  0.5  0.64  1.0
  C  C5  2  0.38  0.5  0.88  1.0

Na Na Na Na Na Na C C
Na Na Na Na Na Na C C 0 6 o o - 0 3 o o - 1 6 o o - 1 2 o o - 2 7 o o o 2 3 o o o 3 7 o o o 4 7 o o o 5 6 o o - 