data_[Cr21Si18]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Cr  1.6600  1.4000  0.9400
  Si  1.9000  1.1000  0.5400
]
_symmetry_space_group_name_H-M [R-3m]
_cell_length_a [4.8157]
_cell_length_b [4.8157]
_cell_length_c [24.1193]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [166]
_chemical_formula_structural [Cr7Si6]
_chemical_formula_sum '[Cr21 Si18]'
_cell_volume [484.4174]
_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
[
  Cr  Cr0  18  0.0058  0.5029  0.9141  1
  Cr  Cr1  3  -0.0000  -0.0000  0.5000  1
  Si  Si2  6  0.0000  0.0000  0.0494  1
  Si  Si3  6  0.0000  0.0000  0.1539  1
  Si  Si4  6  0.0000  0.0000  0.3339  1
]