data_Sr2MgHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.76
_cell_length_b   5.76
_cell_length_c   4.13
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Sr2MgHg
_chemical_formula_sum   'Sr2 Mg1 Hg1'
_cell_volume   137.07
_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
  Sr  Sr2  1  0.0  0.88  0.06  1.0
  Sr  Sr3  1  0.88  0.0  0.06  1.0
  Mg  Mg1  1  0.0  0.0  0.0  1.0
  Hg  Hg0  1  0.88  0.88  0.0  1.0

data_Sr2MgHg
_symmetry_space_group_name_H-M   Cm
_cell_length_a   8.15
_cell_length_b   8.15
_cell_length_c   4.13
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Sr2MgHg
_chemical_formula_sum   'Sr4 Mg2 Hg2'
_cell_volume   274.15
_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+1/2, y+1/2, z'
  4  '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
  Sr  Sr0  4  0.44  0.44  0.06  1.0
  Mg  Mg1  2  0.0  0.0  0.0  1.0
  Hg  Hg2  2  0.38  0.5  0.0  1.0

Sr Sr Mg Hg
Sr Sr Mg Hg 0 3 - o o 0 2 o + o 1 3 o - o 1 2 + o o 