data_[K6Cr3As6O21]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  K  0.8200  2.2000  1.5200
  Cr  1.6600  1.4000  0.9400
  As  2.1800  1.1500  0.6600
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [R-3m]
_cell_length_a [5.7784]
_cell_length_b [5.7784]
_cell_length_c [21.0500]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [166]
_chemical_formula_structural [K2CrAs2O7]
_chemical_formula_sum '[K6 Cr3 As6 O21]'
_cell_volume [608.6815]
_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
[
  K  K0  6  0.0000  0.0000  0.2587  1
  Cr  Cr1  3  -0.0000  -0.0000  0.5000  1
  As  As2  6  0.0000  0.0000  0.0865  1
  O  O3  18  0.0006  0.5003  0.7732  1
  O  O4  3  0.0000  0.0000  0.0000  1
]