data_Na2TlSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.87
_cell_length_b   3.87
_cell_length_c   6.87
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2TlSe
_chemical_formula_sum   'Na2 Tl1 Se1'
_cell_volume   103.12
_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  Na0  1  0.94  0.94  0.51  1.0
  Na  Na1  1  0.94  0.94  0.36  1.0
  Tl  Tl3  1  0.0  0.0  0.44  1.0
  Se  Se2  1  0.0  0.0  0.0  1.0

data_Na2TlSe
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.48
_cell_length_b   5.48
_cell_length_c   6.87
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Na2TlSe
_chemical_formula_sum   'Na4 Tl2 Se2'
_cell_volume   206.23
_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  0.44  0.5  0.36  1.0
  Na  Na1  2  0.44  0.5  0.51  1.0
  Tl  Tl2  2  0.0  0.0  0.44  1.0
  Se  Se3  2  0.0  0.0  0.0  1.0

Na Na Tl Se
Na Na Tl Se 0 2 + + o 1 2 + + o 1 3 + + o 2 3 o o o 