data_[Zn18As21]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Zn  1.6500  1.3500  0.8800
  As  2.1800  1.1500  0.6600
]
_symmetry_space_group_name_H-M [R-3m]
_cell_length_a [5.7452]
_cell_length_b [5.7452]
_cell_length_c [26.4643]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [166]
_chemical_formula_structural [Zn6As7]
_chemical_formula_sum '[Zn18 As21]'
_cell_volume [756.4745]
_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
[
  Zn  Zn0  6  0.0000  0.0000  0.0479  1
  Zn  Zn1  6  0.0000  0.0000  0.1524  1
  Zn  Zn2  6  0.0000  0.0000  0.3357  1
  As  As3  18  0.0076  0.5038  0.9179  1
  As  As4  3  -0.0000  -0.0000  0.5000  1
]