data_NaMgSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.41
_cell_length_b   6.41
_cell_length_c   6.41
_cell_angle_alpha   147.4
_cell_angle_beta   147.4
_cell_angle_gamma   46.78
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaMgSe
_chemical_formula_sum   'Na1 Mg1 Se1'
_cell_volume   76.3
_cell_formula_units_Z   1
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  Na1  1  0.0  0.0  0.75  1.0
  Mg  Mg0  1  0.0  0.0  0.55  1.0
  Se  Se2  1  0.0  0.0  0.47  1.0

data_NaMgSe
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.09
_cell_length_b   5.09
_cell_length_c   6.41
_cell_angle_alpha   90.0
_cell_angle_beta   113.39
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   NaMgSe
_chemical_formula_sum   'Na2 Mg2 Se2'
_cell_volume   152.6
_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+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  2  0.0  0.0  0.25  1.0
  Mg  Mg1  2  0.0  0.0  0.45  1.0
  Se  Se2  2  0.0  0.0  0.53  1.0

Na Mg Se
Na Mg Se 0 1 o o o 1 2 o o o 