The material described by CeSe2 is Low Tridymite-like structured and crystallizes in the monoclinic P2_1/c space group. There are four inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to one Se(1), one Se(4), one Se(6), and one Se(9) atom to form corner-sharing CeSe4 tetrahedra. In the second Ce site, Ce(2) is bonded to one Se(1), one Se(4), one Se(7), and one Se(8) atom to form corner-sharing CeSe4 tetrahedra. In the third Ce site, Ce(3) is bonded to one Se(2), one Se(5), one Se(7), and one Se(8) atom to form corner-sharing CeSe4 tetrahedra. In the fourth Ce site, Ce(4) is bonded to one Se(3), one Se(5), one Se(6), and one Se(9) atom to form corner-sharing CeSe4 tetrahedra. There are nine inequivalent Se sites. In the first Se site, Se(6) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(4) atom. In the second Se site, Se(7) is bonded in a bent 150 degrees geometry to one Ce(2) and one Ce(3) atom. In the third Se site, Se(8) is bonded in a distorted bent 150 degrees geometry to one Ce(2) and one Ce(3) atom. In the fourth Se site, Se(9) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(4) atom. In the fifth Se site, Se(1) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(2) atom. In the sixth Se site, Se(2) is bonded in a linear geometry to two equivalent Ce(3) atoms. In the seventh Se site, Se(3) is bonded in a linear geometry to two equivalent Ce(4) atoms. In the eighth Se site, Se(4) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(2) atom. In the ninth Se site, Se(5) is bonded in a bent 150 degrees geometry to one Ce(3) and one Ce(4) atom. is represented by the CIF card [CIF]
data_CeSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.980
_cell_length_b   14.830
_cell_length_c   14.835
_cell_angle_alpha   90.594
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   2855.552
_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  0.874  0.835  0.648  1.0
  Ce  Ce1  1  0.374  0.165  0.852  1.0
  Ce  Ce2  1  0.126  0.165  0.352  1.0
  Ce  Ce3  1  0.626  0.835  0.148  1.0
  Ce  Ce4  1  0.402  0.342  0.157  1.0
  Ce  Ce5  1  0.902  0.658  0.343  1.0
  Ce  Ce6  1  0.598  0.658  0.843  1.0
  Ce  Ce7  1  0.098  0.342  0.657  1.0
  Ce  Ce8  1  0.649  0.405  0.412  1.0
  Ce  Ce9  1  0.149  0.595  0.088  1.0
  Ce  Ce10  1  0.351  0.595  0.588  1.0
  Ce  Ce11  1  0.851  0.405  0.912  1.0
  Ce  Ce12  1  0.134  0.896  0.906  1.0
  Ce  Ce13  1  0.634  0.104  0.594  1.0
  Ce  Ce14  1  0.866  0.104  0.094  1.0
  Ce  Ce15  1  0.366  0.896  0.406  1.0
  Se  Se16  1  0.271  0.277  0.284  1.0
  Se  Se17  1  0.771  0.723  0.216  1.0
  Se  Se18  1  0.729  0.723  0.716  1.0
  Se  Se19  1  0.229  0.277  0.784  1.0
  Se  Se20  1  0.500  0.500  0.500  1.0
  Se  Se21  1  0.000  0.500  0.000  1.0
  Se  Se22  1  0.000  0.000  0.000  1.0
  Se  Se23  1  0.500  0.000  0.500  1.0
  Se  Se24  1  0.425  0.218  0.022  1.0
  Se  Se25  1  0.925  0.782  0.478  1.0
  Se  Se26  1  0.575  0.782  0.978  1.0
  Se  Se27  1  0.075  0.218  0.522  1.0
  Se  Se28  1  0.193  0.753  0.006  1.0
  Se  Se29  1  0.693  0.247  0.494  1.0
  Se  Se30  1  0.807  0.247  0.994  1.0
  Se  Se31  1  0.307  0.753  0.506  1.0
  Se  Se32  1  0.804  0.007  0.638  1.0
  Se  Se33  1  0.304  0.993  0.862  1.0
  Se  Se34  1  0.196  0.993  0.362  1.0
  Se  Se35  1  0.696  0.007  0.138  1.0
  Se  Se36  1  0.329  0.501  0.092  1.0
  Se  Se37  1  0.829  0.499  0.408  1.0
  Se  Se38  1  0.671  0.499  0.908  1.0
  Se  Se39  1  0.171  0.501  0.592  1.0
  Se  Se40  1  0.587  0.371  0.240  1.0
  Se  Se41  1  0.087  0.629  0.260  1.0
  Se  Se42  1  0.413  0.629  0.760  1.0
  Se  Se43  1  0.913  0.371  0.740  1.0
  Se  Se44  1  0.046  0.832  0.752  1.0
  Se  Se45  1  0.546  0.168  0.748  1.0
  Se  Se46  1  0.954  0.168  0.248  1.0
  Se  Se47  1  0.454  0.832  0.252  1.0
[/CIF]
.
The material described by CeSe2 is Low Tridymite-like structured and crystallizes in the monoclinic P2_1/c space group. There are four inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to one Se(1), one Se(4), one Se(6), and one Se(9) atom to form corner-sharing CeSe4 tetrahedra. In the second Ce site, Ce(2) is bonded to one Se(1), one Se(4), one Se(7), and one Se(8) atom to form corner-sharing CeSe4 tetrahedra. In the third Ce site, Ce(3) is bonded to one Se(2), one Se(5), one Se(7), and one Se(8) atom to form corner-sharing CeSe4 tetrahedra. In the fourth Ce site, Ce(4) is bonded to one Se(3), one Se(5), one Se(6), and one Se(9) atom to form corner-sharing CeSe4 tetrahedra. There are nine inequivalent Se sites. In the first Se site, Se(6) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(4) atom. In the second Se site, Se(7) is bonded in a bent 150 degrees geometry to one Ce(2) and one Ce(3) atom. In the third Se site, Se(8) is bonded in a distorted bent 150 degrees geometry to one Ce(2) and one Ce(3) atom. In the fourth Se site, Se(9) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(4) atom. In the fifth Se site, Se(1) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(2) atom. In the sixth Se site, Se(2) is bonded in a linear geometry to two equivalent Ce(3) atoms. In the seventh Se site, Se(3) is bonded in a linear geometry to two equivalent Ce(4) atoms. In the eighth Se site, Se(4) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(2) atom. In the ninth Se site, Se(5) is bonded in a bent 150 degrees geometry to one Ce(3) and one Ce(4) atom. is represented by the CIF card [CIF]
data_CeSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.980
_cell_length_b   14.830
_cell_length_c   14.835
_cell_angle_alpha   90.594
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   2855.552
_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  0.874  0.835  0.648  1.0
  Ce  Ce1  1  0.374  0.165  0.852  1.0
  Ce  Ce2  1  0.126  0.165  0.352  1.0
  Ce  Ce3  1  0.626  0.835  0.148  1.0
  Ce  Ce4  1  0.402  0.342  0.157  1.0
  Ce  Ce5  1  0.902  0.658  0.343  1.0
  Ce  Ce6  1  0.598  0.658  0.843  1.0
  Ce  Ce7  1  0.098  0.342  0.657  1.0
  Ce  Ce8  1  0.649  0.405  0.412  1.0
  Ce  Ce9  1  0.149  0.595  0.088  1.0
  Ce  Ce10  1  0.351  0.595  0.588  1.0
  Ce  Ce11  1  0.851  0.405  0.912  1.0
  Ce  Ce12  1  0.134  0.896  0.906  1.0
  Ce  Ce13  1  0.634  0.104  0.594  1.0
  Ce  Ce14  1  0.866  0.104  0.094  1.0
  Ce  Ce15  1  0.366  0.896  0.406  1.0
  Se  Se16  1  0.271  0.277  0.284  1.0
  Se  Se17  1  0.771  0.723  0.216  1.0
  Se  Se18  1  0.729  0.723  0.716  1.0
  Se  Se19  1  0.229  0.277  0.784  1.0
  Se  Se20  1  0.500  0.500  0.500  1.0
  Se  Se21  1  0.000  0.500  0.000  1.0
  Se  Se22  1  0.000  0.000  0.000  1.0
  Se  Se23  1  0.500  0.000  0.500  1.0
  Se  Se24  1  0.425  0.218  0.022  1.0
  Se  Se25  1  0.925  0.782  0.478  1.0
  Se  Se26  1  0.575  0.782  0.978  1.0
  Se  Se27  1  0.075  0.218  0.522  1.0
  Se  Se28  1  0.193  0.753  0.006  1.0
  Se  Se29  1  0.693  0.247  0.494  1.0
  Se  Se30  1  0.807  0.247  0.994  1.0
  Se  Se31  1  0.307  0.753  0.506  1.0
  Se  Se32  1  0.804  0.007  0.638  1.0
  Se  Se33  1  0.304  0.993  0.862  1.0
  Se  Se34  1  0.196  0.993  0.362  1.0
  Se  Se35  1  0.696  0.007  0.138  1.0
  Se  Se36  1  0.329  0.501  0.092  1.0
  Se  Se37  1  0.829  0.499  0.408  1.0
  Se  Se38  1  0.671  0.499  0.908  1.0
  Se  Se39  1  0.171  0.501  0.592  1.0
  Se  Se40  1  0.587  0.371  0.240  1.0
  Se  Se41  1  0.087  0.629  0.260  1.0
  Se  Se42  1  0.413  0.629  0.760  1.0
  Se  Se43  1  0.913  0.371  0.740  1.0
  Se  Se44  1  0.046  0.832  0.752  1.0
  Se  Se45  1  0.546  0.168  0.748  1.0
  Se  Se46  1  0.954  0.168  0.248  1.0
  Se  Se47  1  0.454  0.832  0.252  1.0
[/CIF]
.