The structure described by Cs2Se crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a square co-planar geometry to four equivalent Se(1) atoms. In the second Cs site, Cs(2) is bonded in a 3-coordinate geometry to three equivalent Se(1) atoms. Se(1) is bonded in a 7-coordinate geometry to three equivalent Cs(2) and four equivalent Cs(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cs2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.616
_cell_length_b   6.616
_cell_length_c   8.473
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   131.497
_symmetry_Int_Tables_number   1
_cell_volume   277.811
_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  0.500  0.500  0.500  1.0
  Cs  Cs1  1  0.500  0.500  0.000  1.0
  Cs  Cs2  1  0.807  0.193  0.250  1.0
  Cs  Cs3  1  0.193  0.807  0.750  1.0
  Se  Se4  1  0.122  0.878  0.250  1.0
  Se  Se5  1  0.878  0.122  0.750  1.0
[/CIF]
.
The structure described by Cs2Se crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a square co-planar geometry to four equivalent Se(1) atoms. In the second Cs site, Cs(2) is bonded in a 3-coordinate geometry to three equivalent Se(1) atoms. Se(1) is bonded in a 7-coordinate geometry to three equivalent Cs(2) and four equivalent Cs(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cs2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.616
_cell_length_b   6.616
_cell_length_c   8.473
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   131.497
_symmetry_Int_Tables_number   1
_cell_volume   277.811
_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  0.500  0.500  0.500  1.0
  Cs  Cs1  1  0.500  0.500  0.000  1.0
  Cs  Cs2  1  0.807  0.193  0.250  1.0
  Cs  Cs3  1  0.193  0.807  0.750  1.0
  Se  Se4  1  0.122  0.878  0.250  1.0
  Se  Se5  1  0.878  0.122  0.750  1.0
[/CIF]
.