The structure described by Ba3Al2As4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 6-coordinate geometry to one As(2), two equivalent As(3), and three equivalent As(1) atoms. In the second Ba site, Ba(2) is bonded to two equivalent As(2) and four equivalent As(1) atoms to form BaAs6 octahedra that share corners with eight equivalent Al(1)As4 tetrahedra, edges with two equivalent Al(1)As4 tetrahedra, and faces with two equivalent Ba(2)As6 octahedra. Al(1) is bonded to one As(2), one As(3), and two equivalent As(1) atoms to form AlAs4 tetrahedra that share corners with four equivalent Ba(2)As6 octahedra,  an edgeedge with one Ba(2)As6 octahedra, and edges with two equivalent Al(1)As4 tetrahedra. The corner-sharing octahedral tilt angles range from 19-63°. There are three inequivalent As sites. In the first As site, As(3) is bonded in a 6-coordinate geometry to four equivalent Ba(1) and two equivalent Al(1) atoms. In the second As site, As(1) is bonded in a 7-coordinate geometry to two equivalent Ba(2), three equivalent Ba(1), and two equivalent Al(1) atoms. In the third As site, As(2) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Al(1) atoms. is represented by the CIF file [CIF]
data_Ba3(AlAs2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.526
_cell_length_b   11.905
_cell_length_c   11.960
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1071.680
_cell_formula_units_Z   4
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  Ba0  1  0.581  0.078  0.361  1.0
  Ba  Ba1  1  0.081  0.422  0.139  1.0
  Ba  Ba2  1  0.419  0.578  0.639  1.0
  Ba  Ba3  1  0.919  0.922  0.861  1.0
  Ba  Ba4  1  0.419  0.922  0.639  1.0
  Ba  Ba5  1  0.919  0.578  0.861  1.0
  Ba  Ba6  1  0.581  0.422  0.361  1.0
  Ba  Ba7  1  0.081  0.078  0.139  1.0
  Ba  Ba8  1  0.594  0.250  0.737  1.0
  Ba  Ba9  1  0.094  0.250  0.763  1.0
  Ba  Ba10  1  0.406  0.750  0.263  1.0
  Ba  Ba11  1  0.906  0.750  0.237  1.0
  Al  Al12  1  0.559  0.125  0.036  1.0
  Al  Al13  1  0.059  0.375  0.464  1.0
  Al  Al14  1  0.441  0.625  0.964  1.0
  Al  Al15  1  0.941  0.875  0.536  1.0
  Al  Al16  1  0.441  0.875  0.964  1.0
  Al  Al17  1  0.941  0.625  0.536  1.0
  Al  Al18  1  0.559  0.375  0.036  1.0
  Al  Al19  1  0.059  0.125  0.464  1.0
  As  As20  1  0.657  0.558  0.113  1.0
  As  As21  1  0.157  0.942  0.387  1.0
  As  As22  1  0.343  0.058  0.887  1.0
  As  As23  1  0.843  0.442  0.613  1.0
  As  As24  1  0.343  0.442  0.887  1.0
  As  As25  1  0.843  0.058  0.613  1.0
  As  As26  1  0.657  0.942  0.113  1.0
  As  As27  1  0.157  0.558  0.387  1.0
  As  As28  1  0.811  0.250  0.972  1.0
  As  As29  1  0.311  0.250  0.528  1.0
  As  As30  1  0.189  0.750  0.028  1.0
  As  As31  1  0.689  0.750  0.472  1.0
  As  As32  1  0.910  0.250  0.328  1.0
  As  As33  1  0.410  0.250  0.172  1.0
  As  As34  1  0.090  0.750  0.672  1.0
  As  As35  1  0.590  0.750  0.828  1.0
[/CIF]
.
The structure described by Ba3Al2As4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 6-coordinate geometry to one As(2), two equivalent As(3), and three equivalent As(1) atoms. In the second Ba site, Ba(2) is bonded to two equivalent As(2) and four equivalent As(1) atoms to form BaAs6 octahedra that share corners with eight equivalent Al(1)As4 tetrahedra, edges with two equivalent Al(1)As4 tetrahedra, and faces with two equivalent Ba(2)As6 octahedra. Al(1) is bonded to one As(2), one As(3), and two equivalent As(1) atoms to form AlAs4 tetrahedra that share corners with four equivalent Ba(2)As6 octahedra,  an edgeedge with one Ba(2)As6 octahedra, and edges with two equivalent Al(1)As4 tetrahedra. The corner-sharing octahedral tilt angles range from 19-63°. There are three inequivalent As sites. In the first As site, As(3) is bonded in a 6-coordinate geometry to four equivalent Ba(1) and two equivalent Al(1) atoms. In the second As site, As(1) is bonded in a 7-coordinate geometry to two equivalent Ba(2), three equivalent Ba(1), and two equivalent Al(1) atoms. In the third As site, As(2) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Al(1) atoms. is represented by the CIF file [CIF]
data_Ba3(AlAs2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.526
_cell_length_b   11.905
_cell_length_c   11.960
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1071.680
_cell_formula_units_Z   4
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  Ba0  1  0.581  0.078  0.361  1.0
  Ba  Ba1  1  0.081  0.422  0.139  1.0
  Ba  Ba2  1  0.419  0.578  0.639  1.0
  Ba  Ba3  1  0.919  0.922  0.861  1.0
  Ba  Ba4  1  0.419  0.922  0.639  1.0
  Ba  Ba5  1  0.919  0.578  0.861  1.0
  Ba  Ba6  1  0.581  0.422  0.361  1.0
  Ba  Ba7  1  0.081  0.078  0.139  1.0
  Ba  Ba8  1  0.594  0.250  0.737  1.0
  Ba  Ba9  1  0.094  0.250  0.763  1.0
  Ba  Ba10  1  0.406  0.750  0.263  1.0
  Ba  Ba11  1  0.906  0.750  0.237  1.0
  Al  Al12  1  0.559  0.125  0.036  1.0
  Al  Al13  1  0.059  0.375  0.464  1.0
  Al  Al14  1  0.441  0.625  0.964  1.0
  Al  Al15  1  0.941  0.875  0.536  1.0
  Al  Al16  1  0.441  0.875  0.964  1.0
  Al  Al17  1  0.941  0.625  0.536  1.0
  Al  Al18  1  0.559  0.375  0.036  1.0
  Al  Al19  1  0.059  0.125  0.464  1.0
  As  As20  1  0.657  0.558  0.113  1.0
  As  As21  1  0.157  0.942  0.387  1.0
  As  As22  1  0.343  0.058  0.887  1.0
  As  As23  1  0.843  0.442  0.613  1.0
  As  As24  1  0.343  0.442  0.887  1.0
  As  As25  1  0.843  0.058  0.613  1.0
  As  As26  1  0.657  0.942  0.113  1.0
  As  As27  1  0.157  0.558  0.387  1.0
  As  As28  1  0.811  0.250  0.972  1.0
  As  As29  1  0.311  0.250  0.528  1.0
  As  As30  1  0.189  0.750  0.028  1.0
  As  As31  1  0.689  0.750  0.472  1.0
  As  As32  1  0.910  0.250  0.328  1.0
  As  As33  1  0.410  0.250  0.172  1.0
  As  As34  1  0.090  0.750  0.672  1.0
  As  As35  1  0.590  0.750  0.828  1.0
[/CIF]
.