data_MgSi2Bi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.33
_cell_length_b   3.33
_cell_length_c   7.68
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   91.42
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgSi2Bi
_chemical_formula_sum   'Mg1 Si2 Bi1'
_cell_volume   84.91
_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
  Mg  Mg1  1  0.0  0.0  0.53  1.0
  Si  Si2  1  0.32  0.0  0.35  1.0
  Si  Si3  1  0.0  0.0  0.43  1.0
  Bi  Bi0  1  0.32  0.0  0.87  1.0

data_MgSi2Bi
_symmetry_space_group_name_H-M   Pm
_cell_length_a   3.33
_cell_length_b   3.33
_cell_length_c   7.68
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   6
_chemical_formula_structural   MgSi2Bi
_chemical_formula_sum   'Mg1 Si2 Bi1'
_cell_volume   84.93
_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
  Mg  Mg0  1  0.0  0.0  0.53  1.0
  Si  Si1  1  0.0  0.0  0.43  1.0
  Si  Si2  1  0.32  0.0  0.35  1.0
  Bi  Bi3  1  0.32  0.0  0.87  1.0

Mg Si Si Bi
Mg Si Si Bi 0 2 o o o 0 3 o o o 0 3 - o o 1 2 o o o 1 3 o o - 2 3 o o o 3 3 o + o 3 3 + o o 