data_[Er18Mg21]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Er  1.2400  1.7500  1.0300
  Mg  1.3100  1.5000  0.8600
]
_symmetry_space_group_name_H-M [R-3m]
_cell_length_a [5.9808]
_cell_length_b [5.9808]
_cell_length_c [33.5802]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [166]
_chemical_formula_structural [Er6Mg7]
_chemical_formula_sum '[Er18 Mg21]'
_cell_volume [1040.2482]
_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
[
  Er  Er0  6  0.0000  0.0000  0.1657  1.0
  Er  Er1  6  0.0000  0.0000  0.3489  1.0
  Er  Er2  6  0.0000  0.0000  0.4527  1.0
  Mg  Mg3  18  0.0038  0.5019  0.4076  1.0
  Mg  Mg4  3  0.0000  0.0000  0.0000  1.0
]