data_BaAl2As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.2
_cell_length_b   6.2
_cell_length_c   6.2
_cell_angle_alpha   137.84
_cell_angle_beta   137.84
_cell_angle_gamma   61.15
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BaAl2As
_chemical_formula_sum   'Ba1 Al2 As1'
_cell_volume   106.3
_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
  Ba  Ba3  1  0.0  0.0  0.34  1.0
  Al  Al0  1  0.0  0.23  0.67  1.0
  Al  Al1  1  0.23  0.0  0.67  1.0
  As  As2  1  0.0  0.0  0.0  1.0

data_BaAl2As
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.31
_cell_length_b   6.31
_cell_length_c   6.2
_cell_angle_alpha   90.0
_cell_angle_beta   120.57
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   BaAl2As
_chemical_formula_sum   'Ba2 Al4 As2'
_cell_volume   212.61
_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  0.16  0.5  0.66  1.0
  Al  Al1  4  0.45  0.12  0.56  1.0
  As  As2  2  0.0  0.0  0.0  1.0

Ba Al Al As
BaAl2As crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two BaAl2As clusters. Ba(1) is bonded in a 3-coordinate geometry to two equivalent Al(1) and one As(1) atom. Both Ba(1)-Al(1) bond lengths are 1.38 Å. The Ba(1)-As(1) bond length is 2.11 Å. Al(1) is bonded in a distorted single-bond geometry to one Ba(1) atom. As(1) is bonded in a single-bond geometry to one Ba(1) atom.