data_[Rb4Ca4Nb4]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Rb  0.8200  2.3500  1.6600
  Ca  1.0000  1.8000  1.1400
  Nb  1.6000  1.4500  0.8200
]
_symmetry_space_group_name_H-M [Cmcm]
_cell_length_a [4.9364]
_cell_length_b [27.2817]
_cell_length_c [4.0138]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [63]
_chemical_formula_structural [RbCaNb]
_chemical_formula_sum '[Rb4 Ca4 Nb4]'
_cell_volume [540.5607]
_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
[
  Rb  Rb0  4  0.0000  0.3263  0.7500  1
  Ca  Ca1  4  0.0000  0.0565  0.7500  1
  Nb  Nb2  4  0.0000  0.4708  0.7500  1
]