data_AlSi2Br
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.72
_cell_length_b   3.72
_cell_length_c   5.81
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   AlSi2Br
_chemical_formula_sum   'Al1 Si2 Br1'
_cell_volume   80.3
_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
  Al  Al0  1  0.0  0.0  0.0  1.0
  Si  Si2  1  0.86  0.0  0.9  1.0
  Si  Si3  1  0.0  0.86  0.9  1.0
  Br  Br1  1  0.86  0.86  0.0  1.0

data_AlSi2Br
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.26
_cell_length_b   5.26
_cell_length_c   5.81
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   AlSi2Br
_chemical_formula_sum   'Al2 Si4 Br2'
_cell_volume   160.6
_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
  Al  Al0  2  0.0  0.0  0.0  1.0
  Si  Si1  4  0.43  0.43  0.9  1.0
  Br  Br2  2  0.36  0.5  -0.0  1.0

Al Si Si Br
Al Si Si Br 0 3 - - o 0 1 - o - 0 2 o - - 1 2 + - o 1 3 o - + 2 3 - o + 
AlSi2Br is Indium-like structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two AlSi2Br clusters. Al(1) is bonded in a 3-coordinate geometry to two equivalent Si(1) and one Br(1) atom. Both Al(1)-Si(1) bond lengths are 0.76 Å. The Al(1)-Br(1) bond length is 0.74 Å. Si(1) is bonded in a 2-coordinate geometry to one Al(1) and one Br(1) atom. The Si(1)-Br(1) bond length is 0.76 Å. Br(1) is bonded in a 3-coordinate geometry to one Al(1) and two equivalent Si(1) atoms.