The crystal structure described by CsAsSe2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 9-coordinate geometry to one As(2), one Se(4), two equivalent Se(2), two equivalent Se(3), and three equivalent Se(1) atoms. In the second Cs site, Cs(2) is bonded in a 10-coordinate geometry to two equivalent As(1), two equivalent Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent Se(4) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Cs(2), one Se(1), one Se(2), and one Se(4) atom. In the second As site, As(2) is bonded in a 3-coordinate geometry to one Cs(1), one Se(2), one Se(3), and one Se(4) atom. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent Cs(2), three equivalent Cs(1), and one As(1) atom. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to two equivalent Cs(1), two equivalent Cs(2), one As(1), and one As(2) atom. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to two equivalent Cs(1), two equivalent Cs(2), and one As(2) atom. In the fourth Se site, Se(4) is bonded in a 2-coordinate geometry to one Cs(1), two equivalent Cs(2), one As(1), and one As(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_CsAsSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   15.133
_cell_length_b   7.248
_cell_length_c   11.361
_cell_angle_alpha   65.273
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1132.005
_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  0.105  0.791  0.435  1.0
  Cs  Cs1  1  0.297  0.315  0.542  1.0
  Cs  Cs2  1  0.203  0.315  0.042  1.0
  Cs  Cs3  1  0.395  0.791  0.935  1.0
  Cs  Cs4  1  0.605  0.209  0.065  1.0
  Cs  Cs5  1  0.895  0.209  0.565  1.0
  Cs  Cs6  1  0.797  0.685  0.958  1.0
  Cs  Cs7  1  0.703  0.685  0.458  1.0
  As  As8  1  0.512  0.457  0.331  1.0
  As  As9  1  0.937  0.085  0.158  1.0
  As  As10  1  0.488  0.543  0.669  1.0
  As  As11  1  0.063  0.915  0.842  1.0
  As  As12  1  0.012  0.543  0.169  1.0
  As  As13  1  0.988  0.457  0.831  1.0
  As  As14  1  0.563  0.085  0.658  1.0
  As  As15  1  0.437  0.915  0.342  1.0
  Se  Se16  1  0.909  0.659  0.650  1.0
  Se  Se17  1  0.591  0.659  0.150  1.0
  Se  Se18  1  0.902  0.722  0.247  1.0
  Se  Se19  1  0.821  0.175  0.257  1.0
  Se  Se20  1  0.179  0.825  0.743  1.0
  Se  Se21  1  0.679  0.175  0.757  1.0
  Se  Se22  1  0.409  0.341  0.850  1.0
  Se  Se23  1  0.122  0.808  0.064  1.0
  Se  Se24  1  0.321  0.825  0.243  1.0
  Se  Se25  1  0.378  0.808  0.564  1.0
  Se  Se26  1  0.878  0.192  0.936  1.0
  Se  Se27  1  0.622  0.192  0.436  1.0
  Se  Se28  1  0.098  0.278  0.753  1.0
  Se  Se29  1  0.402  0.278  0.253  1.0
  Se  Se30  1  0.091  0.341  0.350  1.0
  Se  Se31  1  0.598  0.722  0.747  1.0
[/CIF]
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The crystal structure described by CsAsSe2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 9-coordinate geometry to one As(2), one Se(4), two equivalent Se(2), two equivalent Se(3), and three equivalent Se(1) atoms. In the second Cs site, Cs(2) is bonded in a 10-coordinate geometry to two equivalent As(1), two equivalent Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent Se(4) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Cs(2), one Se(1), one Se(2), and one Se(4) atom. In the second As site, As(2) is bonded in a 3-coordinate geometry to one Cs(1), one Se(2), one Se(3), and one Se(4) atom. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent Cs(2), three equivalent Cs(1), and one As(1) atom. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to two equivalent Cs(1), two equivalent Cs(2), one As(1), and one As(2) atom. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to two equivalent Cs(1), two equivalent Cs(2), and one As(2) atom. In the fourth Se site, Se(4) is bonded in a 2-coordinate geometry to one Cs(1), two equivalent Cs(2), one As(1), and one As(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_CsAsSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   15.133
_cell_length_b   7.248
_cell_length_c   11.361
_cell_angle_alpha   65.273
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1132.005
_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  0.105  0.791  0.435  1.0
  Cs  Cs1  1  0.297  0.315  0.542  1.0
  Cs  Cs2  1  0.203  0.315  0.042  1.0
  Cs  Cs3  1  0.395  0.791  0.935  1.0
  Cs  Cs4  1  0.605  0.209  0.065  1.0
  Cs  Cs5  1  0.895  0.209  0.565  1.0
  Cs  Cs6  1  0.797  0.685  0.958  1.0
  Cs  Cs7  1  0.703  0.685  0.458  1.0
  As  As8  1  0.512  0.457  0.331  1.0
  As  As9  1  0.937  0.085  0.158  1.0
  As  As10  1  0.488  0.543  0.669  1.0
  As  As11  1  0.063  0.915  0.842  1.0
  As  As12  1  0.012  0.543  0.169  1.0
  As  As13  1  0.988  0.457  0.831  1.0
  As  As14  1  0.563  0.085  0.658  1.0
  As  As15  1  0.437  0.915  0.342  1.0
  Se  Se16  1  0.909  0.659  0.650  1.0
  Se  Se17  1  0.591  0.659  0.150  1.0
  Se  Se18  1  0.902  0.722  0.247  1.0
  Se  Se19  1  0.821  0.175  0.257  1.0
  Se  Se20  1  0.179  0.825  0.743  1.0
  Se  Se21  1  0.679  0.175  0.757  1.0
  Se  Se22  1  0.409  0.341  0.850  1.0
  Se  Se23  1  0.122  0.808  0.064  1.0
  Se  Se24  1  0.321  0.825  0.243  1.0
  Se  Se25  1  0.378  0.808  0.564  1.0
  Se  Se26  1  0.878  0.192  0.936  1.0
  Se  Se27  1  0.622  0.192  0.436  1.0
  Se  Se28  1  0.098  0.278  0.753  1.0
  Se  Se29  1  0.402  0.278  0.253  1.0
  Se  Se30  1  0.091  0.341  0.350  1.0
  Se  Se31  1  0.598  0.722  0.747  1.0
[/CIF]
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