data_[Nb18Fe21]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Nb  1.6000  1.4500  0.8200
  Fe  1.8300  1.4000  0.8525
]
_symmetry_space_group_name_H-M [R-3m]
_cell_length_a [4.8844]
_cell_length_b [4.8844]
_cell_length_c [26.2811]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [166]
_chemical_formula_structural [Nb6Fe7]
_chemical_formula_sum '[Nb18 Fe21]'
_cell_volume [542.9928]
_cell_formula_units_Z [3]
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  6  0.0000  0.0000  0.1670  1.0
  Nb  Nb1  6  0.0000  0.0000  0.3462  1.0
  Nb  Nb2  6  0.0000  0.0000  0.4496  1.0
  Fe  Fe3  18  0.0032  0.5016  0.5920  1.0
  Fe  Fe4  3  0.0000  0.0000  0.0000  1.0
]