data_[U4Nb8O28]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  U  1.3800  1.7500  0.9913
  Nb  1.6000  1.4500  0.8200
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [Cmcm]
_cell_length_a [3.8191]
_cell_length_b [21.3615]
_cell_length_c [6.4927]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [63]
_chemical_formula_structural [UNb2O7]
_chemical_formula_sum '[U4 Nb8 O28]'
_cell_volume [529.6872]
_cell_formula_units_Z [4]
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
[
  U  U0  4  0.0000  0.3565  0.7500  1
  Nb  Nb1  4  0.0000  0.1638  0.7500  1
  Nb  Nb2  4  0.0000  0.4762  0.2500  1
  O  O3  8  0.0000  0.1523  0.0506  1
  O  O4  8  0.0000  0.4488  0.5630  1
  O  O5  4  0.0000  0.0481  0.7500  1
  O  O6  4  0.0000  0.2489  0.7500  1
  O  O7  4  0.0000  0.3640  0.2500  1
]