The structure described by CeSe2 is Low Tridymite-like structured and crystallizes in the tetragonal P4_2/nbc space group. Ce(1) is bonded to one Se(1), one Se(2), and two equivalent Se(3) atoms to form corner-sharing CeSe4 tetrahedra. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a bent 150 degrees geometry to two equivalent Ce(1) atoms. In the second Se site, Se(3) is bonded in a bent 150 degrees geometry to two equivalent Ce(1) atoms. In the third Se site, Se(2) is bonded in a linear geometry to two equivalent Ce(1) atoms. is represented by the CIF file [CIF]
data_CeSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   13.760
_cell_length_b   14.939
_cell_length_c   14.939
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   3071.064
_cell_formula_units_Z   16
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
  Ce  Ce0  1  0.062  0.552  0.280  1.0
  Ce  Ce1  1  0.438  0.552  0.720  1.0
  Ce  Ce2  1  0.062  0.052  0.220  1.0
  Ce  Ce3  1  0.438  0.052  0.780  1.0
  Ce  Ce4  1  0.062  0.448  0.720  1.0
  Ce  Ce5  1  0.438  0.448  0.280  1.0
  Ce  Ce6  1  0.062  0.948  0.780  1.0
  Ce  Ce7  1  0.438  0.948  0.220  1.0
  Ce  Ce8  1  0.938  0.280  0.448  1.0
  Ce  Ce9  1  0.562  0.720  0.448  1.0
  Ce  Ce10  1  0.938  0.220  0.948  1.0
  Ce  Ce11  1  0.562  0.780  0.948  1.0
  Ce  Ce12  1  0.938  0.720  0.552  1.0
  Ce  Ce13  1  0.562  0.280  0.552  1.0
  Ce  Ce14  1  0.938  0.780  0.052  1.0
  Ce  Ce15  1  0.562  0.220  0.052  1.0
  Se  Se16  1  0.500  0.621  0.879  1.0
  Se  Se17  1  0.000  0.621  0.121  1.0
  Se  Se18  1  0.500  0.121  0.621  1.0
  Se  Se19  1  0.000  0.121  0.379  1.0
  Se  Se20  1  0.500  0.379  0.121  1.0
  Se  Se21  1  0.000  0.379  0.879  1.0
  Se  Se22  1  0.500  0.879  0.379  1.0
  Se  Se23  1  0.000  0.879  0.621  1.0
  Se  Se24  1  0.750  0.240  0.000  1.0
  Se  Se25  1  0.750  0.740  0.500  1.0
  Se  Se26  1  0.750  0.760  0.000  1.0
  Se  Se27  1  0.750  0.260  0.500  1.0
  Se  Se28  1  0.250  0.000  0.760  1.0
  Se  Se29  1  0.250  0.500  0.260  1.0
  Se  Se30  1  0.250  0.000  0.240  1.0
  Se  Se31  1  0.250  0.500  0.740  1.0
  Se  Se32  1  0.945  0.411  0.322  1.0
  Se  Se33  1  0.555  0.411  0.678  1.0
  Se  Se34  1  0.945  0.911  0.178  1.0
  Se  Se35  1  0.555  0.911  0.822  1.0
  Se  Se36  1  0.945  0.589  0.678  1.0
  Se  Se37  1  0.555  0.589  0.322  1.0
  Se  Se38  1  0.945  0.089  0.822  1.0
  Se  Se39  1  0.555  0.089  0.178  1.0
  Se  Se40  1  0.055  0.322  0.589  1.0
  Se  Se41  1  0.445  0.678  0.589  1.0
  Se  Se42  1  0.055  0.178  0.089  1.0
  Se  Se43  1  0.445  0.822  0.089  1.0
  Se  Se44  1  0.055  0.678  0.411  1.0
  Se  Se45  1  0.445  0.322  0.411  1.0
  Se  Se46  1  0.055  0.822  0.911  1.0
  Se  Se47  1  0.445  0.178  0.911  1.0
[/CIF]
.
The structure described by CeSe2 is Low Tridymite-like structured and crystallizes in the tetragonal P4_2/nbc space group. Ce(1) is bonded to one Se(1), one Se(2), and two equivalent Se(3) atoms to form corner-sharing CeSe4 tetrahedra. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a bent 150 degrees geometry to two equivalent Ce(1) atoms. In the second Se site, Se(3) is bonded in a bent 150 degrees geometry to two equivalent Ce(1) atoms. In the third Se site, Se(2) is bonded in a linear geometry to two equivalent Ce(1) atoms. is represented by the CIF file [CIF]
data_CeSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   13.760
_cell_length_b   14.939
_cell_length_c   14.939
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   3071.064
_cell_formula_units_Z   16
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
  Ce  Ce0  1  0.062  0.552  0.280  1.0
  Ce  Ce1  1  0.438  0.552  0.720  1.0
  Ce  Ce2  1  0.062  0.052  0.220  1.0
  Ce  Ce3  1  0.438  0.052  0.780  1.0
  Ce  Ce4  1  0.062  0.448  0.720  1.0
  Ce  Ce5  1  0.438  0.448  0.280  1.0
  Ce  Ce6  1  0.062  0.948  0.780  1.0
  Ce  Ce7  1  0.438  0.948  0.220  1.0
  Ce  Ce8  1  0.938  0.280  0.448  1.0
  Ce  Ce9  1  0.562  0.720  0.448  1.0
  Ce  Ce10  1  0.938  0.220  0.948  1.0
  Ce  Ce11  1  0.562  0.780  0.948  1.0
  Ce  Ce12  1  0.938  0.720  0.552  1.0
  Ce  Ce13  1  0.562  0.280  0.552  1.0
  Ce  Ce14  1  0.938  0.780  0.052  1.0
  Ce  Ce15  1  0.562  0.220  0.052  1.0
  Se  Se16  1  0.500  0.621  0.879  1.0
  Se  Se17  1  0.000  0.621  0.121  1.0
  Se  Se18  1  0.500  0.121  0.621  1.0
  Se  Se19  1  0.000  0.121  0.379  1.0
  Se  Se20  1  0.500  0.379  0.121  1.0
  Se  Se21  1  0.000  0.379  0.879  1.0
  Se  Se22  1  0.500  0.879  0.379  1.0
  Se  Se23  1  0.000  0.879  0.621  1.0
  Se  Se24  1  0.750  0.240  0.000  1.0
  Se  Se25  1  0.750  0.740  0.500  1.0
  Se  Se26  1  0.750  0.760  0.000  1.0
  Se  Se27  1  0.750  0.260  0.500  1.0
  Se  Se28  1  0.250  0.000  0.760  1.0
  Se  Se29  1  0.250  0.500  0.260  1.0
  Se  Se30  1  0.250  0.000  0.240  1.0
  Se  Se31  1  0.250  0.500  0.740  1.0
  Se  Se32  1  0.945  0.411  0.322  1.0
  Se  Se33  1  0.555  0.411  0.678  1.0
  Se  Se34  1  0.945  0.911  0.178  1.0
  Se  Se35  1  0.555  0.911  0.822  1.0
  Se  Se36  1  0.945  0.589  0.678  1.0
  Se  Se37  1  0.555  0.589  0.322  1.0
  Se  Se38  1  0.945  0.089  0.822  1.0
  Se  Se39  1  0.555  0.089  0.178  1.0
  Se  Se40  1  0.055  0.322  0.589  1.0
  Se  Se41  1  0.445  0.678  0.589  1.0
  Se  Se42  1  0.055  0.178  0.089  1.0
  Se  Se43  1  0.445  0.822  0.089  1.0
  Se  Se44  1  0.055  0.678  0.411  1.0
  Se  Se45  1  0.445  0.322  0.411  1.0
  Se  Se46  1  0.055  0.822  0.911  1.0
  Se  Se47  1  0.445  0.178  0.911  1.0
[/CIF]
.