data_NbSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.76
_cell_length_b   2.76
_cell_length_c   8.66
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   102.26
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NbSi
_chemical_formula_sum   'Nb2 Si2'
_cell_volume   64.71
_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
  Nb  Nb0  1  0.74  0.08  0.22  1.0
  Nb  Nb1  1  0.74  0.92  0.44  1.0
  Si  Si2  1  0.74  0.08  0.42  1.0
  Si  Si3  1  0.74  0.92  0.24  1.0

data_NbSi
_symmetry_space_group_name_H-M   P-1
_cell_length_a   2.76
_cell_length_b   2.76
_cell_length_c   8.66
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   102.26
_symmetry_Int_Tables_number   2
_chemical_formula_structural   NbSi
_chemical_formula_sum   'Nb2 Si2'
_cell_volume   64.71
_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
  Nb  Nb0  2  0.5  0.08  0.89  1.0
  Si  Si1  2  0.5  0.08  0.09  1.0

Nb Nb Si Si
Nb Nb Si Si 0 3 o - o 1 2 o + o 