data_CaHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.99
_cell_length_b   3.99
_cell_length_c   9.57
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CaHg
_chemical_formula_sum   'Ca2 Hg2'
_cell_volume   131.89
_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
  Ca  Ca0  1  0.99  0.15  0.97  1.0
  Ca  Ca1  1  0.0  0.3  0.6  1.0
  Hg  Hg2  1  0.99  0.15  0.74  1.0
  Hg  Hg3  1  0.0  0.3  0.83  1.0

data_CaHg
_symmetry_space_group_name_H-M   C2/m
_cell_length_a   3.99
_cell_length_b   6.91
_cell_length_c   9.57
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   12
_chemical_formula_structural   CaHg
_chemical_formula_sum   'Ca4 Hg4'
_cell_volume   263.77
_cell_formula_units_Z   4
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'
  5  'x+1/2, y+1/2, z'
  6  '-x+1/2, -y+1/2, -z'
  7  '-x+1/2, y+1/2, -z'
  8  '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
  Ca  Ca0  4  0.08  0.0  0.31  1.0
  Hg  Hg1  4  0.08  0.0  0.54  1.0

Ca Ca Hg Hg