The structure described by Co(SiSe2)2 crystallizes in the monoclinic C2/m space group. Co(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form CoSe6 octahedra that share corners with twelve equivalent Si(1)Se6 octahedra, edges with two equivalent Co(1)Se6 octahedra, and faces with two equivalent Si(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 44-53°. Si(1) is bonded to three equivalent Se(1) and three equivalent Se(2) atoms to form SiSe6 octahedra that share corners with six equivalent Co(1)Se6 octahedra, edges with six equivalent Si(1)Se6 octahedra, and  a faceface with one Co(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 44-53°. There are two inequivalent Se sites. In the first Se site, Se(2) is bonded in a rectangular see-saw-like geometry to one Co(1) and three equivalent Si(1) atoms. In the second Se site, Se(1) is bonded to two equivalent Co(1) and three equivalent Si(1) atoms to form a mixture of distorted edge and corner-sharing SeCo2Si3 square pyramids. is represented by the CIF file [CIF]
data_Co(SiSe2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.924
_cell_length_b   6.924
_cell_length_c   6.265
_cell_angle_alpha   64.191
_cell_angle_beta   64.191
_cell_angle_gamma   30.163
_symmetry_Int_Tables_number   1
_cell_volume   134.710
_cell_formula_units_Z   1
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
  Co  Co0  1  0.000  0.000  0.000  1.0
  Si  Si1  1  0.264  0.264  0.715  1.0
  Si  Si2  1  0.736  0.736  0.285  1.0
  Se  Se3  1  0.381  0.381  0.975  1.0
  Se  Se4  1  0.619  0.619  0.025  1.0
  Se  Se5  1  0.117  0.117  0.563  1.0
  Se  Se6  1  0.883  0.883  0.437  1.0
[/CIF]
.
The structure described by Co(SiSe2)2 crystallizes in the monoclinic C2/m space group. Co(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form CoSe6 octahedra that share corners with twelve equivalent Si(1)Se6 octahedra, edges with two equivalent Co(1)Se6 octahedra, and faces with two equivalent Si(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 44-53°. Si(1) is bonded to three equivalent Se(1) and three equivalent Se(2) atoms to form SiSe6 octahedra that share corners with six equivalent Co(1)Se6 octahedra, edges with six equivalent Si(1)Se6 octahedra, and  a faceface with one Co(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 44-53°. There are two inequivalent Se sites. In the first Se site, Se(2) is bonded in a rectangular see-saw-like geometry to one Co(1) and three equivalent Si(1) atoms. In the second Se site, Se(1) is bonded to two equivalent Co(1) and three equivalent Si(1) atoms to form a mixture of distorted edge and corner-sharing SeCo2Si3 square pyramids. is represented by the CIF file [CIF]
data_Co(SiSe2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.924
_cell_length_b   6.924
_cell_length_c   6.265
_cell_angle_alpha   64.191
_cell_angle_beta   64.191
_cell_angle_gamma   30.163
_symmetry_Int_Tables_number   1
_cell_volume   134.710
_cell_formula_units_Z   1
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
  Co  Co0  1  0.000  0.000  0.000  1.0
  Si  Si1  1  0.264  0.264  0.715  1.0
  Si  Si2  1  0.736  0.736  0.285  1.0
  Se  Se3  1  0.381  0.381  0.975  1.0
  Se  Se4  1  0.619  0.619  0.025  1.0
  Se  Se5  1  0.117  0.117  0.563  1.0
  Se  Se6  1  0.883  0.883  0.437  1.0
[/CIF]
.