data_FeBr3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.95
_cell_length_b   8.95
_cell_length_c   8.95
_cell_angle_alpha   22.84
_cell_angle_beta   22.84
_cell_angle_gamma   22.84
_symmetry_Int_Tables_number   1
_chemical_formula_structural   FeBr3
_chemical_formula_sum   'Fe1 Br3'
_cell_volume   94.92
_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
  Fe  Fe3  1  0.0  0.0  0.0  1.0
  Br  Br0  1  0.0  0.0  0.75  1.0
  Br  Br1  1  0.0  0.0  0.07  1.0
  Br  Br2  1  0.0  0.0  0.39  1.0

data_FeBr3
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.14
_cell_length_b   3.55
_cell_length_c   8.95
_cell_angle_alpha   90.0
_cell_angle_beta   103.22
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   FeBr3
_chemical_formula_sum   'Fe2 Br6'
_cell_volume   189.84
_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
  Fe  Fe0  2  0.0  0.0  0.0  1.0
  Br  Br1  2  -0.0  0.0  0.61  1.0
  Br  Br2  2  -0.0  0.0  0.93  1.0
  Br  Br3  2  -0.0  0.0  0.25  1.0

Fe Br Br Br
FeBr3 crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two FeBr3 clusters. Fe(1) is bonded in a distorted single-bond geometry to one Br(1) and one Br(2) atom. The Fe(1)-Br(1) bond length is 2.19 Å. The Fe(1)-Br(2) bond length is 0.66 Å. There are three inequivalent Br sites. In the first Br site, Br(1) is bonded in a single-bond geometry to one Fe(1) atom. In the second Br site, Br(2) is bonded in a single-bond geometry to one Fe(1) and one Br(3) atom. The Br(2)-Br(3) bond length is 2.86 Å. In the third Br site, Br(3) is bonded in a single-bond geometry to one Br(2) atom.