data_Si2HgSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.11
_cell_length_b   6.11
_cell_length_c   6.11
_cell_angle_alpha   142.73
_cell_angle_beta   142.73
_cell_angle_gamma   53.73
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si2HgSe
_chemical_formula_sum   'Si2 Hg1 Se1'
_cell_volume   83.0
_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
  Si  Si2  1  0.0  0.95  0.72  1.0
  Si  Si3  1  0.0  0.0  0.0  1.0
  Hg  Hg0  1  0.95  0.0  0.72  1.0
  Se  Se1  1  0.0  0.0  0.45  1.0

data_Si2HgSe
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.9
_cell_length_b   3.9
_cell_length_c   6.11
_cell_angle_alpha   108.63
_cell_angle_beta   108.63
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si2HgSe
_chemical_formula_sum   'Si2 Hg1 Se1'
_cell_volume   83.0
_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
  Si  Si0  1  0.0  0.0  0.0  1.0
  Si  Si1  1  0.77  0.72  0.77  1.0
  Hg  Hg2  1  0.72  0.77  0.77  1.0
  Se  Se3  1  0.45  0.45  0.45  1.0

Si Si Hg Se
Si Si Hg Se 0 2 - + o 0 1 o + + 0 3 o + o 1 2 - o - 2 3 + o o 