data_Mg2Br
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.99
_cell_length_b   4.99
_cell_length_c   3.76
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2Br
_chemical_formula_sum   'Mg2 Br1'
_cell_volume   81.15
_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  0.5  0.44  0.69  1.0
  Mg  Mg2  1  0.0  0.88  0.06  1.0
  Br  Br0  1  0.0  0.0  0.0  1.0

data_Mg2Br
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.76
_cell_length_b   4.99
_cell_length_c   4.99
_cell_angle_alpha   120.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2Br
_chemical_formula_sum   'Mg2 Br1'
_cell_volume   81.15
_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  Mg0  1  0.06  0.0  0.88  1.0
  Mg  Mg1  1  0.69  0.5  0.44  1.0
  Br  Br2  1  0.0  0.0  0.0  1.0

Mg Mg Br
Mg Mg Br 0 2 o o + 0 2 + + + 0 1 o - + 0 1 + o + 1 2 o + o 
Mg2Br is Hg_xSn structured and crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one Mg2Br cluster. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a single-bond geometry to one Br(1) atom. The Mg(1)-Br(1) bond length is 2.62 Å. In the second Mg site, Mg(2) is bonded in a single-bond geometry to one Br(1) atom. The Mg(2)-Br(1) bond length is 0.63 Å. Br(1) is bonded in a single-bond geometry to one Mg(1) and one Mg(2) atom.