data_NiHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.55
_cell_length_b   3.02
_cell_length_c   4.59
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NiHg
_chemical_formula_sum   'Ni2 Hg2'
_cell_volume   62.9
_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
  Ni  Ni2  1  0.41  0.0  0.01  1.0
  Ni  Ni3  1  0.14  0.0  0.58  1.0
  Hg  Hg0  1  0.41  0.51  0.35  1.0
  Hg  Hg1  1  0.14  0.51  0.24  1.0

data_NiHg
_symmetry_space_group_name_H-M   P2/m
_cell_length_a   4.55
_cell_length_b   3.02
_cell_length_c   4.59
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   10
_chemical_formula_structural   NiHg
_chemical_formula_sum   'Ni2 Hg2'
_cell_volume   62.9
_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, y, -z'
  4  '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
  Ni  Ni0  2  0.14  0.0  0.71  1.0
  Hg  Hg1  2  0.14  0.5  0.05  1.0

Ni Ni Hg Hg