The material described by Cs3AlAs2 crystallizes in the monoclinic P2_1/c space group. There are six inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 5-coordinate geometry to one Al(1), one As(2), one As(4), and two equivalent As(3) atoms. In the second Cs site, Cs(2) is bonded in a 5-coordinate geometry to one Al(2), two equivalent As(1), and two equivalent As(2) atoms. In the third Cs site, Cs(3) is bonded in a 4-coordinate geometry to one As(1), one As(4), and two equivalent As(2) atoms. In the fourth Cs site, Cs(4) is bonded in a 3-coordinate geometry to one Al(1), one As(3), and one As(4) atom. In the fifth Cs site, Cs(5) is bonded in a 3-coordinate geometry to one As(1), one As(2), and one As(4) atom. In the sixth Cs site, Cs(6) is bonded in a 4-coordinate geometry to one As(2), one As(3), and two equivalent As(4) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 3-coordinate geometry to one Cs(1), one Cs(4), one As(2), and two equivalent As(1) atoms. In the second Al site, Al(2) is bonded in a distorted trigonal planar geometry to one Cs(2), one As(4), and two equivalent As(3) atoms. There are four inequivalent As sites. In the first As site, As(1) is bonded in a 2-coordinate geometry to one Cs(3), one Cs(5), two equivalent Cs(2), and two equivalent Al(1) atoms. In the second As site, As(2) is bonded in a 8-coordinate geometry to one Cs(1), one Cs(5), one Cs(6), two equivalent Cs(2), two equivalent Cs(3), and one Al(1) atom. In the third As site, As(3) is bonded in a 2-coordinate geometry to one Cs(4), one Cs(6), two equivalent Cs(1), and two equivalent Al(2) atoms. In the fourth As site, As(4) is bonded in a distorted single-bond geometry to one Cs(1), one Cs(3), one Cs(4), one Cs(5), two equivalent Cs(6), and one Al(2) atom. is represented by the CIF file [CIF]
data_Cs3AlAs2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.922
_cell_length_b   11.529
_cell_length_c   19.591
_cell_angle_alpha   80.127
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1985.214
_cell_formula_units_Z   8
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
  Cs  Cs0  1  0.569  0.624  0.610  1.0
  Cs  Cs1  1  0.977  0.850  0.468  1.0
  Cs  Cs2  1  0.557  0.083  0.256  1.0
  Cs  Cs3  1  0.588  0.262  0.578  1.0
  Cs  Cs4  1  0.057  0.917  0.244  1.0
  Cs  Cs5  1  0.383  0.707  0.161  1.0
  Cs  Cs6  1  0.412  0.738  0.422  1.0
  Cs  Cs7  1  0.258  0.361  0.712  1.0
  Cs  Cs8  1  0.758  0.639  0.788  1.0
  Cs  Cs9  1  0.742  0.639  0.288  1.0
  Cs  Cs10  1  0.523  0.850  0.968  1.0
  Cs  Cs11  1  0.117  0.707  0.661  1.0
  Cs  Cs12  1  0.943  0.083  0.756  1.0
  Cs  Cs13  1  0.617  0.293  0.839  1.0
  Cs  Cs14  1  0.883  0.293  0.339  1.0
  Cs  Cs15  1  0.088  0.738  0.922  1.0
  Cs  Cs16  1  0.431  0.376  0.390  1.0
  Cs  Cs17  1  0.069  0.376  0.890  1.0
  Cs  Cs18  1  0.931  0.624  0.110  1.0
  Cs  Cs19  1  0.912  0.262  0.078  1.0
  Cs  Cs20  1  0.242  0.361  0.212  1.0
  Cs  Cs21  1  0.023  0.150  0.532  1.0
  Cs  Cs22  1  0.443  0.917  0.744  1.0
  Cs  Cs23  1  0.477  0.150  0.032  1.0
  Al  Al24  1  0.613  0.956  0.554  1.0
  Al  Al25  1  0.387  0.044  0.446  1.0
  Al  Al26  1  0.946  0.463  0.572  1.0
  Al  Al27  1  0.054  0.537  0.428  1.0
  Al  Al28  1  0.887  0.956  0.054  1.0
  Al  Al29  1  0.446  0.537  0.928  1.0
  Al  Al30  1  0.554  0.463  0.072  1.0
  Al  Al31  1  0.113  0.044  0.946  1.0
  As  As32  1  0.841  0.057  0.936  1.0
  As  As33  1  0.209  0.104  0.360  1.0
  As  As34  1  0.709  0.896  0.140  1.0
  As  As35  1  0.294  0.491  0.032  1.0
  As  As36  1  0.359  0.597  0.813  1.0
  As  As37  1  0.659  0.057  0.436  1.0
  As  As38  1  0.794  0.509  0.468  1.0
  As  As39  1  0.641  0.403  0.187  1.0
  As  As40  1  0.159  0.943  0.064  1.0
  As  As41  1  0.291  0.104  0.860  1.0
  As  As42  1  0.341  0.943  0.564  1.0
  As  As43  1  0.859  0.403  0.687  1.0
  As  As44  1  0.141  0.597  0.313  1.0
  As  As45  1  0.791  0.896  0.640  1.0
  As  As46  1  0.706  0.509  0.968  1.0
  As  As47  1  0.206  0.491  0.532  1.0
[/CIF]
.
The material described by Cs3AlAs2 crystallizes in the monoclinic P2_1/c space group. There are six inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 5-coordinate geometry to one Al(1), one As(2), one As(4), and two equivalent As(3) atoms. In the second Cs site, Cs(2) is bonded in a 5-coordinate geometry to one Al(2), two equivalent As(1), and two equivalent As(2) atoms. In the third Cs site, Cs(3) is bonded in a 4-coordinate geometry to one As(1), one As(4), and two equivalent As(2) atoms. In the fourth Cs site, Cs(4) is bonded in a 3-coordinate geometry to one Al(1), one As(3), and one As(4) atom. In the fifth Cs site, Cs(5) is bonded in a 3-coordinate geometry to one As(1), one As(2), and one As(4) atom. In the sixth Cs site, Cs(6) is bonded in a 4-coordinate geometry to one As(2), one As(3), and two equivalent As(4) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 3-coordinate geometry to one Cs(1), one Cs(4), one As(2), and two equivalent As(1) atoms. In the second Al site, Al(2) is bonded in a distorted trigonal planar geometry to one Cs(2), one As(4), and two equivalent As(3) atoms. There are four inequivalent As sites. In the first As site, As(1) is bonded in a 2-coordinate geometry to one Cs(3), one Cs(5), two equivalent Cs(2), and two equivalent Al(1) atoms. In the second As site, As(2) is bonded in a 8-coordinate geometry to one Cs(1), one Cs(5), one Cs(6), two equivalent Cs(2), two equivalent Cs(3), and one Al(1) atom. In the third As site, As(3) is bonded in a 2-coordinate geometry to one Cs(4), one Cs(6), two equivalent Cs(1), and two equivalent Al(2) atoms. In the fourth As site, As(4) is bonded in a distorted single-bond geometry to one Cs(1), one Cs(3), one Cs(4), one Cs(5), two equivalent Cs(6), and one Al(2) atom. is represented by the CIF file [CIF]
data_Cs3AlAs2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.922
_cell_length_b   11.529
_cell_length_c   19.591
_cell_angle_alpha   80.127
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1985.214
_cell_formula_units_Z   8
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
  Cs  Cs0  1  0.569  0.624  0.610  1.0
  Cs  Cs1  1  0.977  0.850  0.468  1.0
  Cs  Cs2  1  0.557  0.083  0.256  1.0
  Cs  Cs3  1  0.588  0.262  0.578  1.0
  Cs  Cs4  1  0.057  0.917  0.244  1.0
  Cs  Cs5  1  0.383  0.707  0.161  1.0
  Cs  Cs6  1  0.412  0.738  0.422  1.0
  Cs  Cs7  1  0.258  0.361  0.712  1.0
  Cs  Cs8  1  0.758  0.639  0.788  1.0
  Cs  Cs9  1  0.742  0.639  0.288  1.0
  Cs  Cs10  1  0.523  0.850  0.968  1.0
  Cs  Cs11  1  0.117  0.707  0.661  1.0
  Cs  Cs12  1  0.943  0.083  0.756  1.0
  Cs  Cs13  1  0.617  0.293  0.839  1.0
  Cs  Cs14  1  0.883  0.293  0.339  1.0
  Cs  Cs15  1  0.088  0.738  0.922  1.0
  Cs  Cs16  1  0.431  0.376  0.390  1.0
  Cs  Cs17  1  0.069  0.376  0.890  1.0
  Cs  Cs18  1  0.931  0.624  0.110  1.0
  Cs  Cs19  1  0.912  0.262  0.078  1.0
  Cs  Cs20  1  0.242  0.361  0.212  1.0
  Cs  Cs21  1  0.023  0.150  0.532  1.0
  Cs  Cs22  1  0.443  0.917  0.744  1.0
  Cs  Cs23  1  0.477  0.150  0.032  1.0
  Al  Al24  1  0.613  0.956  0.554  1.0
  Al  Al25  1  0.387  0.044  0.446  1.0
  Al  Al26  1  0.946  0.463  0.572  1.0
  Al  Al27  1  0.054  0.537  0.428  1.0
  Al  Al28  1  0.887  0.956  0.054  1.0
  Al  Al29  1  0.446  0.537  0.928  1.0
  Al  Al30  1  0.554  0.463  0.072  1.0
  Al  Al31  1  0.113  0.044  0.946  1.0
  As  As32  1  0.841  0.057  0.936  1.0
  As  As33  1  0.209  0.104  0.360  1.0
  As  As34  1  0.709  0.896  0.140  1.0
  As  As35  1  0.294  0.491  0.032  1.0
  As  As36  1  0.359  0.597  0.813  1.0
  As  As37  1  0.659  0.057  0.436  1.0
  As  As38  1  0.794  0.509  0.468  1.0
  As  As39  1  0.641  0.403  0.187  1.0
  As  As40  1  0.159  0.943  0.064  1.0
  As  As41  1  0.291  0.104  0.860  1.0
  As  As42  1  0.341  0.943  0.564  1.0
  As  As43  1  0.859  0.403  0.687  1.0
  As  As44  1  0.141  0.597  0.313  1.0
  As  As45  1  0.791  0.896  0.640  1.0
  As  As46  1  0.706  0.509  0.968  1.0
  As  As47  1  0.206  0.491  0.532  1.0
[/CIF]
.