data_RbHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.33
_cell_length_b   4.33
_cell_length_c   5.56
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   RbHg
_chemical_formula_sum   'Rb1 Hg1'
_cell_volume   90.01
_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
  Rb  Rb1  1  0.0  0.0  0.0  1.0
  Hg  Hg0  1  0.0  0.5  0.78  1.0

data_RbHg
_symmetry_space_group_name_H-M   Cmm2
_cell_length_a   4.33
_cell_length_b   7.49
_cell_length_c   5.56
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   35
_chemical_formula_structural   RbHg
_chemical_formula_sum   'Rb2 Hg2'
_cell_volume   180.03
_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'
  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
  Rb  Rb0  2  0.0  0.0  0.0  1.0
  Hg  Hg1  2  0.0  0.5  0.22  1.0

Rb Hg