The compound described by Cs2SiSe4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 9-coordinate geometry to two equivalent Se(1), three equivalent Se(3), and four equivalent Se(2) atoms. In the second Cs site, Cs(2) is bonded in a 9-coordinate geometry to two equivalent Se(3), three equivalent Se(1), and four equivalent Se(2) atoms. Si(1) is bonded in a tetrahedral geometry to one Se(1), one Se(3), and two equivalent Se(2) atoms. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent Cs(1), three equivalent Cs(2), and one Si(1) atom. In the second Se site, Se(2) is bonded in a distorted single-bond geometry to two equivalent Cs(1), two equivalent Cs(2), and one Si(1) atom. In the third Se site, Se(3) is bonded in a distorted single-bond geometry to two equivalent Cs(2), three equivalent Cs(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cs2SiSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.712
_cell_length_b   8.591
_cell_length_c   9.747
_cell_angle_alpha   67.241
_cell_angle_beta   66.696
_cell_angle_gamma   63.330
_symmetry_Int_Tables_number   1
_cell_volume   512.473
_cell_formula_units_Z   2
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  0.590  0.674  0.146  1.0
  Cs  Cs1  1  0.160  0.965  0.715  1.0
  Cs  Cs2  1  0.410  0.326  0.854  1.0
  Cs  Cs3  1  0.840  0.035  0.285  1.0
  Si  Si4  1  0.845  0.610  0.700  1.0
  Si  Si5  1  0.155  0.390  0.300  1.0
  Se  Se6  1  0.310  0.112  0.268  1.0
  Se  Se7  1  0.671  0.638  0.538  1.0
  Se  Se8  1  0.690  0.888  0.732  1.0
  Se  Se9  1  0.848  0.362  0.462  1.0
  Se  Se10  1  0.874  0.362  0.889  1.0
  Se  Se11  1  0.126  0.638  0.111  1.0
  Se  Se12  1  0.329  0.362  0.462  1.0
  Se  Se13  1  0.152  0.638  0.538  1.0
[/CIF]
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The compound described by Cs2SiSe4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 9-coordinate geometry to two equivalent Se(1), three equivalent Se(3), and four equivalent Se(2) atoms. In the second Cs site, Cs(2) is bonded in a 9-coordinate geometry to two equivalent Se(3), three equivalent Se(1), and four equivalent Se(2) atoms. Si(1) is bonded in a tetrahedral geometry to one Se(1), one Se(3), and two equivalent Se(2) atoms. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent Cs(1), three equivalent Cs(2), and one Si(1) atom. In the second Se site, Se(2) is bonded in a distorted single-bond geometry to two equivalent Cs(1), two equivalent Cs(2), and one Si(1) atom. In the third Se site, Se(3) is bonded in a distorted single-bond geometry to two equivalent Cs(2), three equivalent Cs(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cs2SiSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.712
_cell_length_b   8.591
_cell_length_c   9.747
_cell_angle_alpha   67.241
_cell_angle_beta   66.696
_cell_angle_gamma   63.330
_symmetry_Int_Tables_number   1
_cell_volume   512.473
_cell_formula_units_Z   2
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  0.590  0.674  0.146  1.0
  Cs  Cs1  1  0.160  0.965  0.715  1.0
  Cs  Cs2  1  0.410  0.326  0.854  1.0
  Cs  Cs3  1  0.840  0.035  0.285  1.0
  Si  Si4  1  0.845  0.610  0.700  1.0
  Si  Si5  1  0.155  0.390  0.300  1.0
  Se  Se6  1  0.310  0.112  0.268  1.0
  Se  Se7  1  0.671  0.638  0.538  1.0
  Se  Se8  1  0.690  0.888  0.732  1.0
  Se  Se9  1  0.848  0.362  0.462  1.0
  Se  Se10  1  0.874  0.362  0.889  1.0
  Se  Se11  1  0.126  0.638  0.111  1.0
  Se  Se12  1  0.329  0.362  0.462  1.0
  Se  Se13  1  0.152  0.638  0.538  1.0
[/CIF]
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