The crystal structure described by CeSe2 crystallizes in the triclinic P1 space group. There are four inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to one Se(1), one Se(3), one Se(4), one Se(5), one Se(6), and one Se(7) atom to form a mixture of distorted edge, face, and corner-sharing CeSe6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 25°. In the second Ce site, Ce(2) is bonded in a 5-coordinate geometry to one Se(1), one Se(2), one Se(3), one Se(7), and one Se(8) atom. In the third Ce site, Ce(3) is bonded to one Se(1), one Se(2), one Se(4), one Se(5), one Se(6), and one Se(7) atom to form a mixture of distorted edge and corner-sharing CeSe6 octahedra. The corner-sharing octahedral tilt angles range from 19-47°. In the fourth Ce site, Ce(4) is bonded to one Se(3), one Se(4), one Se(5), one Se(6), one Se(7), and one Se(8) atom to form a mixture of edge, face, and corner-sharing CeSe6 octahedra. The corner-sharing octahedral tilt angles range from 19-47°. There are eight inequivalent Se sites. In the first Se site, Se(1) is bonded in a T-shaped geometry to one Ce(1), one Ce(2), and one Ce(3) atom. In the second Se site, Se(2) is bonded in a water-like geometry to one Ce(2) and one Ce(3) atom. In the third Se site, Se(3) is bonded in a distorted T-shaped geometry to one Ce(1), one Ce(2), and one Ce(4) atom. In the fourth Se site, Se(4) is bonded in a distorted trigonal non-coplanar geometry to one Ce(1), one Ce(3), and one Ce(4) atom. In the fifth Se site, Se(5) is bonded in a 3-coordinate geometry to one Ce(1), one Ce(3), and one Ce(4) atom. In the sixth Se site, Se(6) is bonded in a T-shaped geometry to one Ce(1), one Ce(3), and one Ce(4) atom. In the seventh Se site, Se(7) is bonded in a distorted see-saw-like geometry to one Ce(1), one Ce(2), one Ce(3), and one Ce(4) atom. In the eighth Se site, Se(8) is bonded in a linear geometry to one Ce(2) 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   7.643
_cell_length_b   7.728
_cell_length_c   7.793
_cell_angle_alpha   98.641
_cell_angle_beta   109.826
_cell_angle_gamma   90.107
_symmetry_Int_Tables_number   1
_cell_volume   427.417
_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  0.966  0.999  0.953  1.0
  Ce  Ce1  1  0.706  0.508  0.586  1.0
  Ce  Ce2  1  0.555  0.857  0.183  1.0
  Ce  Ce3  1  0.115  0.093  0.537  1.0
  Se  Se4  1  0.744  0.702  0.942  1.0
  Se  Se5  1  0.514  0.516  0.220  1.0
  Se  Se6  1  0.995  0.314  0.797  1.0
  Se  Se7  1  0.218  0.879  0.266  1.0
  Se  Se8  1  0.810  0.161  0.223  1.0
  Se  Se9  1  0.290  0.931  0.848  1.0
  Se  Se10  1  0.809  0.863  0.556  1.0
  Se  Se11  1  0.414  0.312  0.584  1.0
[/CIF]
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The crystal structure described by CeSe2 crystallizes in the triclinic P1 space group. There are four inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to one Se(1), one Se(3), one Se(4), one Se(5), one Se(6), and one Se(7) atom to form a mixture of distorted edge, face, and corner-sharing CeSe6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 25°. In the second Ce site, Ce(2) is bonded in a 5-coordinate geometry to one Se(1), one Se(2), one Se(3), one Se(7), and one Se(8) atom. In the third Ce site, Ce(3) is bonded to one Se(1), one Se(2), one Se(4), one Se(5), one Se(6), and one Se(7) atom to form a mixture of distorted edge and corner-sharing CeSe6 octahedra. The corner-sharing octahedral tilt angles range from 19-47°. In the fourth Ce site, Ce(4) is bonded to one Se(3), one Se(4), one Se(5), one Se(6), one Se(7), and one Se(8) atom to form a mixture of edge, face, and corner-sharing CeSe6 octahedra. The corner-sharing octahedral tilt angles range from 19-47°. There are eight inequivalent Se sites. In the first Se site, Se(1) is bonded in a T-shaped geometry to one Ce(1), one Ce(2), and one Ce(3) atom. In the second Se site, Se(2) is bonded in a water-like geometry to one Ce(2) and one Ce(3) atom. In the third Se site, Se(3) is bonded in a distorted T-shaped geometry to one Ce(1), one Ce(2), and one Ce(4) atom. In the fourth Se site, Se(4) is bonded in a distorted trigonal non-coplanar geometry to one Ce(1), one Ce(3), and one Ce(4) atom. In the fifth Se site, Se(5) is bonded in a 3-coordinate geometry to one Ce(1), one Ce(3), and one Ce(4) atom. In the sixth Se site, Se(6) is bonded in a T-shaped geometry to one Ce(1), one Ce(3), and one Ce(4) atom. In the seventh Se site, Se(7) is bonded in a distorted see-saw-like geometry to one Ce(1), one Ce(2), one Ce(3), and one Ce(4) atom. In the eighth Se site, Se(8) is bonded in a linear geometry to one Ce(2) 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   7.643
_cell_length_b   7.728
_cell_length_c   7.793
_cell_angle_alpha   98.641
_cell_angle_beta   109.826
_cell_angle_gamma   90.107
_symmetry_Int_Tables_number   1
_cell_volume   427.417
_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  0.966  0.999  0.953  1.0
  Ce  Ce1  1  0.706  0.508  0.586  1.0
  Ce  Ce2  1  0.555  0.857  0.183  1.0
  Ce  Ce3  1  0.115  0.093  0.537  1.0
  Se  Se4  1  0.744  0.702  0.942  1.0
  Se  Se5  1  0.514  0.516  0.220  1.0
  Se  Se6  1  0.995  0.314  0.797  1.0
  Se  Se7  1  0.218  0.879  0.266  1.0
  Se  Se8  1  0.810  0.161  0.223  1.0
  Se  Se9  1  0.290  0.931  0.848  1.0
  Se  Se10  1  0.809  0.863  0.556  1.0
  Se  Se11  1  0.414  0.312  0.584  1.0
[/CIF]
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