data_Na2TaTc
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.25
_cell_length_b   3.25
_cell_length_c   8.99
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2TaTc
_chemical_formula_sum   'Na2 Ta1 Tc1'
_cell_volume   95.0
_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  0.63  0.63  0.5  1.0
  Na  Na1  1  0.0  0.0  0.51  1.0
  Ta  Ta2  1  0.63  0.63  0.15  1.0
  Tc  Tc3  1  0.0  0.0  0.31  1.0

data_Na2TaTc
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.6
_cell_length_b   4.6
_cell_length_c   8.99
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Na2TaTc
_chemical_formula_sum   'Na4 Ta2 Tc2'
_cell_volume   190.01
_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  0.51  1.0
  Na  Na1  2  0.13  0.5  0.5  1.0
  Ta  Ta2  2  0.13  0.5  0.15  1.0
  Tc  Tc3  2  0.0  0.0  0.31  1.0

Na Na Ta Tc
Na Na Ta Tc 0 1 + + o 1 3 o o o 2 3 o + o 2 3 + o o 2 3 + + o 