data_[Cu4Si2Hg2Se8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Cu  1.9000  1.3500  0.8200
  Si  1.9000  1.1000  0.5400
  Hg  2.0000  1.5000  1.2450
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Pmn2_1]
_cell_length_a [8.1244]
_cell_length_b [6.8606]
_cell_length_c [6.6504]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [31]
_chemical_formula_structural [Cu2SiHgSe4]
_chemical_formula_sum '[Cu4 Si2 Hg2 Se8]'
_cell_volume [370.6795]
_cell_formula_units_Z [2]
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
[
  Cu  Cu0  4  0.2475  0.8238  0.5114  1.0
  Si  Si1  2  0.0000  0.6789  0.0003  1.0
  Hg  Hg2  2  0.0000  0.3490  0.5138  1.0
  Se  Se3  4  0.2270  0.8447  0.8738  1.0
  Se  Se4  2  0.0000  0.3490  0.9178  1.0
  Se  Se5  2  0.0000  0.7085  0.3501  1.0
]