data_[Mg6Nb3Fe3O18]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Mg  1.3100  1.5000  0.8600
  Nb  1.6000  1.4500  0.8200
  Fe  1.8300  1.4000  0.8525
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [R3]
_cell_length_a [5.1969]
_cell_length_b [5.1969]
_cell_length_c [14.0529]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [146]
_chemical_formula_structural [Mg2NbFeO6]
_chemical_formula_sum '[Mg6 Nb3 Fe3 O18]'
_cell_volume [328.6910]
_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
[
  Mg  Mg0  3  0.0000  0.0000  0.4797  1.0
  Mg  Mg1  3  0.0000  0.0000  0.9745  1.0
  Nb  Nb2  3  0.0000  0.0000  0.6878  1.0
  Fe  Fe3  3  0.0000  0.0000  0.1904  1.0
  O  O4  9  0.0377  0.3494  0.7505  1.0
  O  O5  9  0.0411  0.6839  0.2516  1.0
]