The crystal structure described by CeSe2 is Low Tridymite-like structured and crystallizes in the triclinic P-1 space group. There are eight inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form corner-sharing CeSe4 tetrahedra. In the second Ce site, Ce(2) is bonded to one Se(1), one Se(3), one Se(5), and one Se(6) atom to form corner-sharing CeSe4 tetrahedra. In the third Ce site, Ce(3) is bonded to one Se(10), one Se(7), one Se(8), and one Se(9) atom to form corner-sharing CeSe4 tetrahedra. In the fourth Ce site, Ce(4) is bonded to one Se(11), one Se(12), one Se(13), and one Se(7) atom to form corner-sharing CeSe4 tetrahedra. In the fifth Ce site, Ce(5) is bonded to one Se(10), one Se(14), one Se(2), and one Se(8) atom to form corner-sharing CeSe4 tetrahedra. In the sixth Ce site, Ce(6) is bonded to one Se(14), one Se(15), one Se(5), and one Se(9) atom to form corner-sharing CeSe4 tetrahedra. In the seventh Ce site, Ce(7) is bonded to one Se(13), one Se(15), one Se(16), and one Se(6) atom to form corner-sharing CeSe4 tetrahedra. In the eighth Ce site, Ce(8) is bonded to one Se(11), one Se(12), one Se(16), and one Se(4) atom to form corner-sharing CeSe4 tetrahedra. There are sixteen inequivalent Se sites. In the first Se site, Se(1) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(2) atom. In the second Se site, Se(2) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(5) atom. In the third Se site, Se(3) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(2) atom. In the fourth Se site, Se(4) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(8) atom. In the fifth Se site, Se(5) is bonded in a bent 150 degrees geometry to one Ce(2) and one Ce(6) atom. In the sixth Se site, Se(6) is bonded in a bent 150 degrees geometry to one Ce(2) and one Ce(7) atom. In the seventh Se site, Se(7) is bonded in a bent 150 degrees geometry to one Ce(3) and one Ce(4) atom. In the eighth Se site, Se(8) is bonded in a bent 150 degrees geometry to one Ce(3) and one Ce(5) atom. In the ninth Se site, Se(9) is bonded in a bent 150 degrees geometry to one Ce(3) and one Ce(6) atom. In the tenth Se site, Se(10) is bonded in a bent 150 degrees geometry to one Ce(3) and one Ce(5) atom. In the eleventh Se site, Se(11) is bonded in a bent 150 degrees geometry to one Ce(4) and one Ce(8) atom. In the twelfth Se site, Se(12) is bonded in a bent 150 degrees geometry to one Ce(4) and one Ce(8) atom. In the thirteenth Se site, Se(13) is bonded in a linear geometry to one Ce(4) and one Ce(7) atom. In the fourteenth Se site, Se(14) is bonded in a bent 150 degrees geometry to one Ce(5) and one Ce(6) atom. In the fifteenth Se site, Se(15) is bonded in a bent 150 degrees geometry to one Ce(6) and one Ce(7) atom. In the sixteenth Se site, Se(16) is bonded in a bent 150 degrees geometry to one Ce(7) and one Ce(8) atom. is represented by the CIF file [CIF]
data_CeSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.502
_cell_length_b   19.350
_cell_length_c   19.565
_cell_angle_alpha   105.286
_cell_angle_beta   94.871
_cell_angle_gamma   95.987
_symmetry_Int_Tables_number   1
_cell_volume   4509.533
_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  0.389  0.640  0.643  1.0
  Ce  Ce1  1  0.611  0.360  0.357  1.0
  Ce  Ce2  1  0.780  0.587  0.571  1.0
  Ce  Ce3  1  0.220  0.413  0.429  1.0
  Ce  Ce4  1  0.590  0.858  0.358  1.0
  Ce  Ce5  1  0.410  0.142  0.642  1.0
  Ce  Ce6  1  0.430  0.638  0.143  1.0
  Ce  Ce7  1  0.570  0.362  0.857  1.0
  Ce  Ce8  1  0.329  0.866  0.558  1.0
  Ce  Ce9  1  0.671  0.134  0.442  1.0
  Ce  Ce10  1  0.955  0.761  0.432  1.0
  Ce  Ce11  1  0.045  0.239  0.568  1.0
  Ce  Ce12  1  0.075  0.540  0.242  1.0
  Ce  Ce13  1  0.925  0.460  0.758  1.0
  Ce  Ce14  1  0.696  0.441  0.124  1.0
  Ce  Ce15  1  0.304  0.559  0.876  1.0
  Se  Se16  1  0.599  0.634  0.623  1.0
  Se  Se17  1  0.401  0.366  0.377  1.0
  Se  Se18  1  0.330  0.768  0.635  1.0
  Se  Se19  1  0.670  0.232  0.365  1.0
  Se  Se20  1  0.271  0.530  0.542  1.0
  Se  Se21  1  0.729  0.470  0.458  1.0
  Se  Se22  1  0.356  0.625  0.774  1.0
  Se  Se23  1  0.644  0.375  0.226  1.0
  Se  Se24  1  0.892  0.693  0.529  1.0
  Se  Se25  1  0.108  0.307  0.471  1.0
  Se  Se26  1  0.900  0.550  0.675  1.0
  Se  Se27  1  0.100  0.450  0.325  1.0
  Se  Se28  1  0.493  0.772  0.231  1.0
  Se  Se29  1  0.507  0.228  0.769  1.0
  Se  Se30  1  0.467  0.835  0.459  1.0
  Se  Se31  1  0.533  0.165  0.541  1.0
  Se  Se32  1  0.790  0.823  0.385  1.0
  Se  Se33  1  0.210  0.177  0.615  1.0
  Se  Se34  1  0.605  0.998  0.357  1.0
  Se  Se35  1  0.395  0.002  0.643  1.0
  Se  Se36  1  0.600  0.562  0.142  1.0
  Se  Se37  1  0.400  0.438  0.858  1.0
  Se  Se38  1  0.375  0.646  0.008  1.0
  Se  Se39  1  0.625  0.354  0.992  1.0
  Se  Se40  1  0.262  0.570  0.189  1.0
  Se  Se41  1  0.738  0.430  0.811  1.0
  Se  Se42  1  0.127  0.862  0.494  1.0
  Se  Se43  1  0.873  0.138  0.506  1.0
  Se  Se44  1  0.019  0.666  0.321  1.0
  Se  Se45  1  0.981  0.334  0.679  1.0
  Se  Se46  1  0.914  0.478  0.136  1.0
  Se  Se47  1  0.086  0.522  0.864  1.0
[/CIF]
.
The crystal structure described by CeSe2 is Low Tridymite-like structured and crystallizes in the triclinic P-1 space group. There are eight inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form corner-sharing CeSe4 tetrahedra. In the second Ce site, Ce(2) is bonded to one Se(1), one Se(3), one Se(5), and one Se(6) atom to form corner-sharing CeSe4 tetrahedra. In the third Ce site, Ce(3) is bonded to one Se(10), one Se(7), one Se(8), and one Se(9) atom to form corner-sharing CeSe4 tetrahedra. In the fourth Ce site, Ce(4) is bonded to one Se(11), one Se(12), one Se(13), and one Se(7) atom to form corner-sharing CeSe4 tetrahedra. In the fifth Ce site, Ce(5) is bonded to one Se(10), one Se(14), one Se(2), and one Se(8) atom to form corner-sharing CeSe4 tetrahedra. In the sixth Ce site, Ce(6) is bonded to one Se(14), one Se(15), one Se(5), and one Se(9) atom to form corner-sharing CeSe4 tetrahedra. In the seventh Ce site, Ce(7) is bonded to one Se(13), one Se(15), one Se(16), and one Se(6) atom to form corner-sharing CeSe4 tetrahedra. In the eighth Ce site, Ce(8) is bonded to one Se(11), one Se(12), one Se(16), and one Se(4) atom to form corner-sharing CeSe4 tetrahedra. There are sixteen inequivalent Se sites. In the first Se site, Se(1) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(2) atom. In the second Se site, Se(2) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(5) atom. In the third Se site, Se(3) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(2) atom. In the fourth Se site, Se(4) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(8) atom. In the fifth Se site, Se(5) is bonded in a bent 150 degrees geometry to one Ce(2) and one Ce(6) atom. In the sixth Se site, Se(6) is bonded in a bent 150 degrees geometry to one Ce(2) and one Ce(7) atom. In the seventh Se site, Se(7) is bonded in a bent 150 degrees geometry to one Ce(3) and one Ce(4) atom. In the eighth Se site, Se(8) is bonded in a bent 150 degrees geometry to one Ce(3) and one Ce(5) atom. In the ninth Se site, Se(9) is bonded in a bent 150 degrees geometry to one Ce(3) and one Ce(6) atom. In the tenth Se site, Se(10) is bonded in a bent 150 degrees geometry to one Ce(3) and one Ce(5) atom. In the eleventh Se site, Se(11) is bonded in a bent 150 degrees geometry to one Ce(4) and one Ce(8) atom. In the twelfth Se site, Se(12) is bonded in a bent 150 degrees geometry to one Ce(4) and one Ce(8) atom. In the thirteenth Se site, Se(13) is bonded in a linear geometry to one Ce(4) and one Ce(7) atom. In the fourteenth Se site, Se(14) is bonded in a bent 150 degrees geometry to one Ce(5) and one Ce(6) atom. In the fifteenth Se site, Se(15) is bonded in a bent 150 degrees geometry to one Ce(6) and one Ce(7) atom. In the sixteenth Se site, Se(16) is bonded in a bent 150 degrees geometry to one Ce(7) and one Ce(8) atom. is represented by the CIF file [CIF]
data_CeSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.502
_cell_length_b   19.350
_cell_length_c   19.565
_cell_angle_alpha   105.286
_cell_angle_beta   94.871
_cell_angle_gamma   95.987
_symmetry_Int_Tables_number   1
_cell_volume   4509.533
_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  0.389  0.640  0.643  1.0
  Ce  Ce1  1  0.611  0.360  0.357  1.0
  Ce  Ce2  1  0.780  0.587  0.571  1.0
  Ce  Ce3  1  0.220  0.413  0.429  1.0
  Ce  Ce4  1  0.590  0.858  0.358  1.0
  Ce  Ce5  1  0.410  0.142  0.642  1.0
  Ce  Ce6  1  0.430  0.638  0.143  1.0
  Ce  Ce7  1  0.570  0.362  0.857  1.0
  Ce  Ce8  1  0.329  0.866  0.558  1.0
  Ce  Ce9  1  0.671  0.134  0.442  1.0
  Ce  Ce10  1  0.955  0.761  0.432  1.0
  Ce  Ce11  1  0.045  0.239  0.568  1.0
  Ce  Ce12  1  0.075  0.540  0.242  1.0
  Ce  Ce13  1  0.925  0.460  0.758  1.0
  Ce  Ce14  1  0.696  0.441  0.124  1.0
  Ce  Ce15  1  0.304  0.559  0.876  1.0
  Se  Se16  1  0.599  0.634  0.623  1.0
  Se  Se17  1  0.401  0.366  0.377  1.0
  Se  Se18  1  0.330  0.768  0.635  1.0
  Se  Se19  1  0.670  0.232  0.365  1.0
  Se  Se20  1  0.271  0.530  0.542  1.0
  Se  Se21  1  0.729  0.470  0.458  1.0
  Se  Se22  1  0.356  0.625  0.774  1.0
  Se  Se23  1  0.644  0.375  0.226  1.0
  Se  Se24  1  0.892  0.693  0.529  1.0
  Se  Se25  1  0.108  0.307  0.471  1.0
  Se  Se26  1  0.900  0.550  0.675  1.0
  Se  Se27  1  0.100  0.450  0.325  1.0
  Se  Se28  1  0.493  0.772  0.231  1.0
  Se  Se29  1  0.507  0.228  0.769  1.0
  Se  Se30  1  0.467  0.835  0.459  1.0
  Se  Se31  1  0.533  0.165  0.541  1.0
  Se  Se32  1  0.790  0.823  0.385  1.0
  Se  Se33  1  0.210  0.177  0.615  1.0
  Se  Se34  1  0.605  0.998  0.357  1.0
  Se  Se35  1  0.395  0.002  0.643  1.0
  Se  Se36  1  0.600  0.562  0.142  1.0
  Se  Se37  1  0.400  0.438  0.858  1.0
  Se  Se38  1  0.375  0.646  0.008  1.0
  Se  Se39  1  0.625  0.354  0.992  1.0
  Se  Se40  1  0.262  0.570  0.189  1.0
  Se  Se41  1  0.738  0.430  0.811  1.0
  Se  Se42  1  0.127  0.862  0.494  1.0
  Se  Se43  1  0.873  0.138  0.506  1.0
  Se  Se44  1  0.019  0.666  0.321  1.0
  Se  Se45  1  0.981  0.334  0.679  1.0
  Se  Se46  1  0.914  0.478  0.136  1.0
  Se  Se47  1  0.086  0.522  0.864  1.0
[/CIF]
.