data_HfSiBr2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.98
_cell_length_b   4.98
_cell_length_c   3.33
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HfSiBr2
_chemical_formula_sum   'Hf1 Si1 Br2'
_cell_volume   82.67
_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
  Hf  Hf2  1  0.49  0.49  0.0  1.0
  Si  Si3  1  0.0  0.0  0.0  1.0
  Br  Br0  1  0.0  0.49  0.67  1.0
  Br  Br1  1  0.49  0.0  0.67  1.0

data_HfSiBr2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   7.04
_cell_length_b   7.04
_cell_length_c   3.33
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   HfSiBr2
_chemical_formula_sum   'Hf2 Si2 Br4'
_cell_volume   165.35
_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
  Hf  Hf0  2  0.49  0.0  0.0  1.0
  Si  Si1  2  0.0  0.0  0.0  1.0
  Br  Br2  4  0.25  0.25  0.67  1.0

Hf Si Br Br
HfSiBr2 crystallizes in the monoclinic Cm space group. Hf(1) is bonded in a 4-coordinate geometry to eight equivalent Br(1) atoms. There are a spread of Hf(1)-Br(1) bond distances ranging from 2.68-3.37 Å. Si(1) is bonded in a 4-coordinate geometry to four equivalent Br(1) atoms. There are two shorter (2.68 Å) and two longer (2.77 Å) Si(1)-Br(1) bond lengths. Br(1) is bonded in a 6-coordinate geometry to four equivalent Hf(1) and two equivalent Si(1) atoms.