data_BaAlB2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.25
_cell_length_b   3.25
_cell_length_c   6.38
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BaAlB2
_chemical_formula_sum   'Ba1 Al1 B2'
_cell_volume   67.42
_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
  Ba  Ba3  1  0.0  0.0  0.19  1.0
  Al  Al0  1  0.0  0.0  0.0  1.0
  B  B1  1  0.63  0.63  0.82  1.0
  B  B2  1  0.63  0.63  0.56  1.0

data_BaAlB2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.6
_cell_length_b   4.6
_cell_length_c   6.38
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   BaAlB2
_chemical_formula_sum   'Ba2 Al2 B4'
_cell_volume   134.85
_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
  Ba  Ba0  2  0.0  0.0  0.19  1.0
  Al  Al1  2  0.0  0.0  0.0  1.0
  B  B2  2  0.13  0.5  0.56  1.0
  B  B3  2  0.13  0.5  0.82  1.0

Ba Al B B
Ba Al B B 0 1 o o o 2 3 o o o 
BaAlB2 crystallizes in the monoclinic Cm space group. Ba(1) is bonded in a single-bond geometry to one Al(1) and three equivalent B(2) atoms. The Ba(1)-Al(1) bond length is 1.21 Å. There is one shorter (2.93 Å) and two longer (3.35 Å) Ba(1)-B(2) bond lengths. Al(1) is bonded in a distorted single-bond geometry to one Ba(1) and three equivalent B(1) atoms. There is one shorter (2.07 Å) and two longer (2.64 Å) Al(1)-B(1) bond lengths. There are two inequivalent B sites. In the first B site, B(1) is bonded in a 4-coordinate geometry to three equivalent Al(1) and one B(2) atom. The B(1)-B(2) bond length is 1.65 Å. In the second B site, B(2) is bonded in a 4-coordinate geometry to three equivalent Ba(1) and one B(1) atom.