data_HgSeCl2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.23
_cell_length_b   5.23
_cell_length_c   5.23
_cell_angle_alpha   123.69
_cell_angle_beta   123.69
_cell_angle_gamma   83.73
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HgSeCl2
_chemical_formula_sum   'Hg1 Se1 Cl2'
_cell_volume   94.75
_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
  Hg  Hg2  1  0.0  0.0  0.89  1.0
  Se  Se3  1  0.0  0.0  0.0  1.0
  Cl  Cl0  1  0.47  0.0  0.95  1.0
  Cl  Cl1  1  0.0  0.47  0.95  1.0

data_HgSeCl2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.98
_cell_length_b   6.98
_cell_length_c   5.23
_cell_angle_alpha   90.0
_cell_angle_beta   131.86
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   HgSeCl2
_chemical_formula_sum   'Hg2 Se2 Cl4'
_cell_volume   189.51
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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
  Hg  Hg0  2  0.11  0.0  0.11  1.0
  Se  Se1  2  0.0  0.0  0.0  1.0
  Cl  Cl2  4  0.29  0.23  0.52  1.0

Hg Se Cl Cl