data_MgBr3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.72
_cell_length_b   3.72
_cell_length_c   11.14
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.39
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgBr3
_chemical_formula_sum   'Mg1 Br3'
_cell_volume   132.71
_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  Mg3  1  0.0  0.0  0.0  1.0
  Br  Br0  1  0.85  0.0  0.35  1.0
  Br  Br1  1  0.0  0.0  0.57  1.0
  Br  Br2  1  0.85  0.0  0.78  1.0

data_MgBr3
_symmetry_space_group_name_H-M   Cm
_cell_length_a   3.72
_cell_length_b   6.41
_cell_length_c   11.14
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   MgBr3
_chemical_formula_sum   'Mg2 Br6'
_cell_volume   265.42
_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
  Mg  Mg0  2  0.0  0.0  0.0  1.0
  Br  Br1  2  0.0  0.0  0.43  1.0
  Br  Br2  2  0.15  0.0  0.22  1.0
  Br  Br3  2  0.15  0.0  0.65  1.0

Mg Br Br Br
Mg Br Br Br 0 3 - o - 1 2 + o o 2 3 - o o 