data_Zn2SiHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.99
_cell_length_b   4.99
_cell_length_c   3.01
_cell_angle_alpha   90.95
_cell_angle_beta   90.95
_cell_angle_gamma   108.94
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Zn2SiHg
_chemical_formula_sum   'Zn2 Si1 Hg1'
_cell_volume   70.96
_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
  Zn  Zn2  1  0.41  0.03  0.5  1.0
  Zn  Zn3  1  0.41  0.97  0.5  1.0
  Si  Si1  1  0.0  0.0  0.0  1.0
  Hg  Hg0  1  0.9  0.0  0.0  1.0

data_Zn2SiHg
_symmetry_space_group_name_H-M   Pm
_cell_length_a   4.99
_cell_length_b   3.01
_cell_length_c   4.99
_cell_angle_alpha   90.0
_cell_angle_beta   108.94
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   6
_chemical_formula_structural   Zn2SiHg
_chemical_formula_sum   'Zn2 Si1 Hg1'
_cell_volume   70.99
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '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  1  0.41  0.5  0.03  1.0
  Zn  Zn1  1  0.41  0.5  0.97  1.0
  Si  Si2  1  0.0  0.0  0.0  1.0
  Hg  Hg3  1  0.9  0.0  0.0  1.0

Zn Zn Si Hg
Zn Zn Si Hg 0 1 o - o 2 3 - o o 