data_Na2As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.36
_cell_length_b   8.36
_cell_length_c   5.0
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   157.38
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2As
_chemical_formula_sum   'Na4 As2'
_cell_volume   134.45
_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  0.64  0.64  0.75  1.0
  Na  Na3  1  0.64  0.69  0.75  1.0
  Na  Na4  1  0.64  0.31  0.25  1.0
  Na  Na5  1  0.64  0.36  0.25  1.0
  As  As0  1  0.64  0.04  0.75  1.0
  As  As1  1  0.64  0.96  0.25  1.0

data_Na2As
_symmetry_space_group_name_H-M   P2_1/m
_cell_length_a   3.28
_cell_length_b   5.0
_cell_length_c   8.36
_cell_angle_alpha   90.0
_cell_angle_beta   101.31
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   11
_chemical_formula_structural   Na2As
_chemical_formula_sum   'Na4 As2'
_cell_volume   134.45
_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, y+1/2, -z'
  4  'x, -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  2  0.31  0.25  0.81  1.0
  Na  Na1  2  0.36  0.25  0.86  1.0
  As  As2  2  0.04  0.75  0.54  1.0

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