data_Mg2BeBr2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.7
_cell_length_b   6.7
_cell_length_c   6.7
_cell_angle_alpha   137.5
_cell_angle_beta   137.5
_cell_angle_gamma   61.67
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2BeBr2
_chemical_formula_sum   'Mg2 Be1 Br2'
_cell_volume   135.4
_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  0.18  1.0
  Mg  Mg4  1  0.0  0.0  0.32  1.0
  Be  Be0  1  0.0  0.0  0.0  1.0
  Br  Br1  1  0.0  0.43  0.87  1.0
  Br  Br2  1  0.43  0.0  0.87  1.0

data_Mg2BeBr2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.86
_cell_length_b   6.86
_cell_length_c   6.7
_cell_angle_alpha   90.0
_cell_angle_beta   120.83
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Mg2BeBr2
_chemical_formula_sum   'Mg4 Be2 Br4'
_cell_volume   270.8
_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  0.18  0.5  0.68  1.0
  Mg  Mg1  2  0.32  0.5  0.82  1.0
  Be  Be2  2  0.0  0.0  0.0  1.0
  Br  Br3  4  0.34  0.21  0.55  1.0

Mg Mg Be Br Br