data_FeSeBr2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.1
_cell_length_b   5.1
_cell_length_c   3.36
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   FeSeBr2
_chemical_formula_sum   'Fe1 Se1 Br2'
_cell_volume   87.28
_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  Fe2  1  0.0  0.0  0.0  1.0
  Se  Se3  1  0.55  0.55  0.0  1.0
  Br  Br0  1  0.55  0.0  0.68  1.0
  Br  Br1  1  0.0  0.55  0.68  1.0

data_FeSeBr2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   7.21
_cell_length_b   7.21
_cell_length_c   3.36
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   FeSeBr2
_chemical_formula_sum   'Fe2 Se2 Br4'
_cell_volume   174.56
_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
  Se  Se1  2  0.05  0.5  0.0  1.0
  Br  Br2  4  0.28  0.28  0.68  1.0

Fe Se Br Br
Fe Se Br Br 0 1 - - o 0 2 - o - 0 2 - o o 0 2 o o - 0 3 o - - 0 3 o - o 0 3 o o - 1 3 o o - 1 3 + o - 1 3 + o o 1 2 o o - 1 2 o + - 1 2 o + o 2 3 + - o 
FeSeBr2 crystallizes in the monoclinic Cm space group. Fe(1) is bonded in a 4-coordinate geometry to six equivalent Br(1) atoms. There are a spread of Fe(1)-Br(1) bond distances ranging from 2.54-3.23 Å. Se(1) is bonded in a 4-coordinate geometry to four equivalent Br(1) atoms. There are two shorter (2.54 Å) and two longer (3.01 Å) Se(1)-Br(1) bond lengths. Br(1) is bonded in a 5-coordinate geometry to three equivalent Fe(1) and two equivalent Se(1) atoms.