data_NaSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.39
_cell_length_b   6.39
_cell_length_c   6.29
_cell_angle_alpha   104.75
_cell_angle_beta   104.75
_cell_angle_gamma   27.34
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaSi2
_chemical_formula_sum   'Na2 Si4'
_cell_volume   113.8
_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  0.89  0.0  0.58  1.0
  Na  Na1  1  0.88  0.0  0.49  1.0
  Si  Si2  1  0.57  0.0  0.63  1.0
  Si  Si3  1  0.47  0.0  0.77  1.0
  Si  Si4  1  0.3  0.0  0.3  1.0
  Si  Si5  1  0.2  0.0  0.44  1.0

data_NaSi2
_symmetry_space_group_name_H-M   P-1
_cell_length_a   3.02
_cell_length_b   6.29
_cell_length_c   6.39
_cell_angle_alpha   104.75
_cell_angle_beta   103.67
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   2
_chemical_formula_structural   NaSi2
_chemical_formula_sum   'Na2 Si4'
_cell_volume   113.8
_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
  Na  Na0  2  0.0  0.46  0.49  1.0
  Si  Si1  2  0.0  0.26  0.91  1.0
  Si  Si2  2  0.0  0.4  0.81  1.0

Na Na Si Si Si Si