The crystal structure described by Cs3AsSe4O crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 1-coordinate geometry to one Se(1), two equivalent Se(2), and one O(1) atom. In the second Cs site, Cs(2) is bonded in a 8-coordinate geometry to one Se(3), two equivalent Se(1), two equivalent Se(2), two equivalent Se(4), and one O(1) atom. In the third Cs site, Cs(3) is bonded in a 9-coordinate geometry to one Se(4), two equivalent Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent O(1) atoms. As(1) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form AsSe4 tetrahedra that share  a cornercorner with one O(1)Cs4Se trigonal bipyramid. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to one Cs(1), two equivalent Cs(2), two equivalent Cs(3), and one As(1) atom to form distorted SeCs5As octahedra that share corners with three equivalent O(1)Cs4Se trigonal bipyramids, edges with two equivalent Se(1)Cs5As octahedra, and edges with two equivalent O(1)Cs4Se trigonal bipyramids. In the second Se site, Se(2) is bonded in a 7-coordinate geometry to two equivalent Cs(1), two equivalent Cs(2), two equivalent Cs(3), and one As(1) atom. In the third Se site, Se(3) is bonded in a 1-coordinate geometry to one Cs(2), two equivalent Cs(3), and one As(1) atom. In the fourth Se site, Se(4) is bonded in a distorted single-bond geometry to one Cs(3), two equivalent Cs(2), one As(1), and one O(1) atom. O(1) is bonded to one Cs(1), one Cs(2), two equivalent Cs(3), and one Se(4) atom to form distorted OCs4Se trigonal bipyramids that share corners with three equivalent Se(1)Cs5As octahedra,  a cornercorner with one As(1)Se4 tetrahedra, edges with two equivalent Se(1)Cs5As octahedra, and  an edgeedge with one O(1)Cs4Se trigonal bipyramid. The corner-sharing octahedral tilt angles range from 30-60°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cs3AsSe4O
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.468
_cell_length_b   10.550
_cell_length_c   15.868
_cell_angle_alpha   90.000
_cell_angle_beta   130.214
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1338.254
_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
  Cs  Cs0  1  0.837  0.826  0.750  1.0
  Cs  Cs1  1  0.837  0.674  0.250  1.0
  Cs  Cs2  1  0.163  0.174  0.250  1.0
  Cs  Cs3  1  0.163  0.326  0.750  1.0
  Cs  Cs4  1  0.259  0.075  0.544  1.0
  Cs  Cs5  1  0.259  0.425  0.044  1.0
  Cs  Cs6  1  0.741  0.925  0.456  1.0
  Cs  Cs7  1  0.741  0.575  0.956  1.0
  Cs  Cs8  1  0.642  0.039  0.957  1.0
  Cs  Cs9  1  0.642  0.461  0.457  1.0
  Cs  Cs10  1  0.358  0.961  0.043  1.0
  Cs  Cs11  1  0.358  0.539  0.543  1.0
  As  As12  1  0.260  0.784  0.734  1.0
  As  As13  1  0.260  0.716  0.234  1.0
  As  As14  1  0.740  0.216  0.266  1.0
  As  As15  1  0.740  0.284  0.766  1.0
  Se  Se16  1  0.483  0.808  0.735  1.0
  Se  Se17  1  0.483  0.692  0.235  1.0
  Se  Se18  1  0.517  0.192  0.265  1.0
  Se  Se19  1  0.517  0.308  0.765  1.0
  Se  Se20  1  0.159  0.984  0.732  1.0
  Se  Se21  1  0.159  0.516  0.232  1.0
  Se  Se22  1  0.841  0.016  0.268  1.0
  Se  Se23  1  0.841  0.484  0.768  1.0
  Se  Se24  1  0.052  0.651  0.594  1.0
  Se  Se25  1  0.052  0.849  0.094  1.0
  Se  Se26  1  0.948  0.349  0.406  1.0
  Se  Se27  1  0.948  0.151  0.906  1.0
  Se  Se28  1  0.366  0.675  0.907  1.0
  Se  Se29  1  0.366  0.825  0.407  1.0
  Se  Se30  1  0.634  0.325  0.093  1.0
  Se  Se31  1  0.634  0.175  0.593  1.0
  O  O32  1  0.557  0.750  0.012  1.0
  O  O33  1  0.557  0.750  0.512  1.0
  O  O34  1  0.443  0.250  0.988  1.0
  O  O35  1  0.443  0.250  0.488  1.0
[/CIF]
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The crystal structure described by Cs3AsSe4O crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 1-coordinate geometry to one Se(1), two equivalent Se(2), and one O(1) atom. In the second Cs site, Cs(2) is bonded in a 8-coordinate geometry to one Se(3), two equivalent Se(1), two equivalent Se(2), two equivalent Se(4), and one O(1) atom. In the third Cs site, Cs(3) is bonded in a 9-coordinate geometry to one Se(4), two equivalent Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent O(1) atoms. As(1) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form AsSe4 tetrahedra that share  a cornercorner with one O(1)Cs4Se trigonal bipyramid. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to one Cs(1), two equivalent Cs(2), two equivalent Cs(3), and one As(1) atom to form distorted SeCs5As octahedra that share corners with three equivalent O(1)Cs4Se trigonal bipyramids, edges with two equivalent Se(1)Cs5As octahedra, and edges with two equivalent O(1)Cs4Se trigonal bipyramids. In the second Se site, Se(2) is bonded in a 7-coordinate geometry to two equivalent Cs(1), two equivalent Cs(2), two equivalent Cs(3), and one As(1) atom. In the third Se site, Se(3) is bonded in a 1-coordinate geometry to one Cs(2), two equivalent Cs(3), and one As(1) atom. In the fourth Se site, Se(4) is bonded in a distorted single-bond geometry to one Cs(3), two equivalent Cs(2), one As(1), and one O(1) atom. O(1) is bonded to one Cs(1), one Cs(2), two equivalent Cs(3), and one Se(4) atom to form distorted OCs4Se trigonal bipyramids that share corners with three equivalent Se(1)Cs5As octahedra,  a cornercorner with one As(1)Se4 tetrahedra, edges with two equivalent Se(1)Cs5As octahedra, and  an edgeedge with one O(1)Cs4Se trigonal bipyramid. The corner-sharing octahedral tilt angles range from 30-60°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cs3AsSe4O
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.468
_cell_length_b   10.550
_cell_length_c   15.868
_cell_angle_alpha   90.000
_cell_angle_beta   130.214
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1338.254
_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
  Cs  Cs0  1  0.837  0.826  0.750  1.0
  Cs  Cs1  1  0.837  0.674  0.250  1.0
  Cs  Cs2  1  0.163  0.174  0.250  1.0
  Cs  Cs3  1  0.163  0.326  0.750  1.0
  Cs  Cs4  1  0.259  0.075  0.544  1.0
  Cs  Cs5  1  0.259  0.425  0.044  1.0
  Cs  Cs6  1  0.741  0.925  0.456  1.0
  Cs  Cs7  1  0.741  0.575  0.956  1.0
  Cs  Cs8  1  0.642  0.039  0.957  1.0
  Cs  Cs9  1  0.642  0.461  0.457  1.0
  Cs  Cs10  1  0.358  0.961  0.043  1.0
  Cs  Cs11  1  0.358  0.539  0.543  1.0
  As  As12  1  0.260  0.784  0.734  1.0
  As  As13  1  0.260  0.716  0.234  1.0
  As  As14  1  0.740  0.216  0.266  1.0
  As  As15  1  0.740  0.284  0.766  1.0
  Se  Se16  1  0.483  0.808  0.735  1.0
  Se  Se17  1  0.483  0.692  0.235  1.0
  Se  Se18  1  0.517  0.192  0.265  1.0
  Se  Se19  1  0.517  0.308  0.765  1.0
  Se  Se20  1  0.159  0.984  0.732  1.0
  Se  Se21  1  0.159  0.516  0.232  1.0
  Se  Se22  1  0.841  0.016  0.268  1.0
  Se  Se23  1  0.841  0.484  0.768  1.0
  Se  Se24  1  0.052  0.651  0.594  1.0
  Se  Se25  1  0.052  0.849  0.094  1.0
  Se  Se26  1  0.948  0.349  0.406  1.0
  Se  Se27  1  0.948  0.151  0.906  1.0
  Se  Se28  1  0.366  0.675  0.907  1.0
  Se  Se29  1  0.366  0.825  0.407  1.0
  Se  Se30  1  0.634  0.325  0.093  1.0
  Se  Se31  1  0.634  0.175  0.593  1.0
  O  O32  1  0.557  0.750  0.012  1.0
  O  O33  1  0.557  0.750  0.512  1.0
  O  O34  1  0.443  0.250  0.988  1.0
  O  O35  1  0.443  0.250  0.488  1.0
[/CIF]
.