data_[K2Ca4Si8O21]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  K  0.8200  2.2000  1.5200
  Ca  1.0000  1.8000  1.1400
  Si  1.9000  1.1000  0.5400
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [P-1]
_cell_length_a [6.7500]
_cell_length_b [7.0111]
_cell_length_c [11.1540]
_cell_angle_alpha [96.6398]
_cell_angle_beta [105.3033]
_cell_angle_gamma [109.4831]
_symmetry_Int_Tables_number [2]
_chemical_formula_structural [K2Ca4Si8O21]
_chemical_formula_sum '[K2 Ca4 Si8 O21]'
_cell_volume [467.7936]
_cell_formula_units_Z [1]
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  2  0.2579  0.2840  0.5643  1
  Ca  Ca1  2  0.3490  0.2187  0.1872  1
  Ca  Ca2  2  0.3726  0.7302  0.0423  1
  Si  Si3  2  0.0979  0.2461  0.8909  1
  Si  Si4  2  0.1348  0.5280  0.2569  1
  Si  Si5  2  0.1722  0.9072  0.7459  1
  Si  Si6  2  0.3296  0.7960  0.5272  1
  O  O7  2  0.0611  0.2777  0.2596  1
  O  O8  2  0.0832  0.4679  0.8533  1
  O  O9  2  0.1226  0.1203  0.7631  1
  O  O10  2  0.1289  0.8799  0.0847  1
  O  O11  2  0.1389  0.6519  0.3919  1
  O  O12  2  0.1805  0.8811  0.5991  1
  O  O13  2  0.3289  0.3203  0.0039  1
  O  O14  2  0.3606  0.5986  0.2251  1
  O  O15  2  0.3862  0.9112  0.8529  1
  O  O16  2  0.4591  0.6763  0.6055  1
  O  O17  1  0.5000  0.0000  0.5000  1
]