data_YAlBr2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.61
_cell_length_b   5.61
_cell_length_c   5.61
_cell_angle_alpha   130.17
_cell_angle_beta   130.17
_cell_angle_gamma   73.13
_symmetry_Int_Tables_number   1
_chemical_formula_structural   YAlBr2
_chemical_formula_sum   'Y1 Al1 Br2'
_cell_volume   100.41
_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
  Y  Y3  1  0.0  0.0  0.5  1.0
  Al  Al0  1  0.0  0.0  0.0  1.0
  Br  Br1  1  0.36  0.0  0.25  1.0
  Br  Br2  1  0.0  0.36  0.25  1.0

data_YAlBr2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.68
_cell_length_b   6.68
_cell_length_c   5.61
_cell_angle_alpha   90.0
_cell_angle_beta   126.56
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   YAlBr2
_chemical_formula_sum   'Y2 Al2 Br4'
_cell_volume   200.82
_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
  Y  Y0  2  0.0  0.0  0.5  1.0
  Al  Al1  2  0.0  0.0  0.0  1.0
  Br  Br2  4  0.32  0.32  0.89  1.0

Y Al Br Br
YAlBr2 crystallizes in the monoclinic Cm space group. Y(1) is bonded in a 8-coordinate geometry to two equivalent Al(1) and six equivalent Br(1) atoms. There is one shorter (2.79 Å) and one longer (2.82 Å) Y(1)-Al(1) bond length. There are a spread of Y(1)-Br(1) bond distances ranging from 2.88-3.28 Å. Al(1) is bonded in a water-like geometry to two equivalent Y(1) and two equivalent Br(1) atoms. Both Al(1)-Br(1) bond lengths are 1.55 Å. Br(1) is bonded in a distorted single-bond geometry to three equivalent Y(1) and one Al(1) atom.