The compound described by CeSe2 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 8-coordinate geometry to one Se(3), one Se(4), two equivalent Se(2), and four equivalent Se(1) atoms. In the second Ce site, Ce(2) is bonded to two equivalent Se(2), three equivalent Se(3), and three equivalent Se(4) atoms to form a mixture of distorted edge and corner-sharing CeSe8 hexagonal bipyramids. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 4-coordinate geometry to four equivalent Ce(1) atoms. In the second Se site, Se(2) is bonded to two equivalent Ce(1) and two equivalent Ce(2) atoms to form distorted corner-sharing SeCe4 trigonal pyramids. In the third Se site, Se(3) is bonded in a 4-coordinate geometry to one Ce(1), three equivalent Ce(2), and two equivalent Se(4) atoms. In the fourth Se site, Se(4) is bonded in a 6-coordinate geometry to one Ce(1), three equivalent Ce(2), and two equivalent Se(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_CeSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.234
_cell_length_b   5.608
_cell_length_c   10.620
_cell_angle_alpha   89.928
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   311.690
_cell_formula_units_Z   4
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  0.250  0.759  0.864  1.0
  Ce  Ce1  1  0.750  0.241  0.136  1.0
  Ce  Ce2  1  0.750  0.256  0.632  1.0
  Ce  Ce3  1  0.250  0.744  0.368  1.0
  Se  Se4  1  0.250  0.258  0.932  1.0
  Se  Se5  1  0.750  0.742  0.068  1.0
  Se  Se6  1  0.750  0.764  0.747  1.0
  Se  Se7  1  0.250  0.236  0.253  1.0
  Se  Se8  1  0.250  0.507  0.614  1.0
  Se  Se9  1  0.750  0.493  0.386  1.0
  Se  Se10  1  0.250  0.015  0.610  1.0
  Se  Se11  1  0.750  0.985  0.390  1.0
[/CIF]
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The compound described by CeSe2 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 8-coordinate geometry to one Se(3), one Se(4), two equivalent Se(2), and four equivalent Se(1) atoms. In the second Ce site, Ce(2) is bonded to two equivalent Se(2), three equivalent Se(3), and three equivalent Se(4) atoms to form a mixture of distorted edge and corner-sharing CeSe8 hexagonal bipyramids. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 4-coordinate geometry to four equivalent Ce(1) atoms. In the second Se site, Se(2) is bonded to two equivalent Ce(1) and two equivalent Ce(2) atoms to form distorted corner-sharing SeCe4 trigonal pyramids. In the third Se site, Se(3) is bonded in a 4-coordinate geometry to one Ce(1), three equivalent Ce(2), and two equivalent Se(4) atoms. In the fourth Se site, Se(4) is bonded in a 6-coordinate geometry to one Ce(1), three equivalent Ce(2), and two equivalent Se(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_CeSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.234
_cell_length_b   5.608
_cell_length_c   10.620
_cell_angle_alpha   89.928
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   311.690
_cell_formula_units_Z   4
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  0.250  0.759  0.864  1.0
  Ce  Ce1  1  0.750  0.241  0.136  1.0
  Ce  Ce2  1  0.750  0.256  0.632  1.0
  Ce  Ce3  1  0.250  0.744  0.368  1.0
  Se  Se4  1  0.250  0.258  0.932  1.0
  Se  Se5  1  0.750  0.742  0.068  1.0
  Se  Se6  1  0.750  0.764  0.747  1.0
  Se  Se7  1  0.250  0.236  0.253  1.0
  Se  Se8  1  0.250  0.507  0.614  1.0
  Se  Se9  1  0.750  0.493  0.386  1.0
  Se  Se10  1  0.250  0.015  0.610  1.0
  Se  Se11  1  0.750  0.985  0.390  1.0
[/CIF]
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