The 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(2), one Se(3), one Se(5), one Se(6), one Se(7), and one Se(8) atom to form distorted CeSe6 octahedra that share  a cornercorner with one Ce(2)Se5 trigonal bipyramid,  a cornercorner with one Ce(4)Se5 trigonal bipyramid,  an edgeedge with one Ce(2)Se5 trigonal bipyramid, edges with two equivalent Ce(4)Se5 trigonal bipyramids, and  an edgeedge with one Ce(3)Se4 trigonal pyramid. In the second Ce site, Ce(2) is bonded to one Se(1), one Se(2), one Se(4), one Se(6), and one Se(7) atom to form CeSe5 trigonal bipyramids that share  a cornercorner with one Ce(1)Se6 octahedra, corners with two equivalent Ce(4)Se5 trigonal bipyramids, corners with two equivalent Ce(3)Se4 trigonal pyramids, and  an edgeedge with one Ce(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 53°. In the third Ce site, Ce(3) is bonded to one Se(1), one Se(3), one Se(4), and one Se(8) atom to form CeSe4 trigonal pyramids that share corners with two equivalent Ce(2)Se5 trigonal bipyramids, corners with two equivalent Ce(4)Se5 trigonal bipyramids, and  an edgeedge with one Ce(1)Se6 octahedra. In the fourth Ce site, Ce(4) is bonded to one Se(3), one Se(5), one Se(6), one Se(7), and one Se(8) atom to form CeSe5 trigonal bipyramids that share  a cornercorner with one Ce(1)Se6 octahedra, corners with two equivalent Ce(2)Se5 trigonal bipyramids, corners with two equivalent Ce(3)Se4 trigonal pyramids, and edges with two equivalent Ce(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 36°. There are eight inequivalent Se sites. In the first Se site, Se(1) is bonded in a bent 120 degrees geometry to one Ce(2) and one Ce(3) atom. In the second Se site, Se(2) is bonded in a bent 120 degrees geometry to one Ce(1) and one Ce(2) atom. In the third Se site, Se(3) is bonded in a distorted T-shaped geometry to one Ce(1), one Ce(3), and one Ce(4) atom. In the fourth Se site, Se(4) is bonded in a bent 120 degrees geometry to one Ce(2) and one Ce(3) atom. In the fifth Se site, Se(5) is bonded in a bent 150 degrees geometry to one Ce(1) 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(2), and one Ce(4) atom. In the seventh Se site, Se(7) is bonded in a trigonal non-coplanar geometry to one Ce(1), one Ce(2), and one Ce(4) atom. In the eighth Se site, Se(8) is bonded in a T-shaped geometry to one Ce(1), 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   7.289
_cell_length_b   7.491
_cell_length_c   10.102
_cell_angle_alpha   95.434
_cell_angle_beta   96.919
_cell_angle_gamma   104.388
_symmetry_Int_Tables_number   1
_cell_volume   525.911
_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  0.517  0.107  0.093  1.0
  Ce  Ce1  1  0.995  0.016  0.808  1.0
  Ce  Ce2  1  0.451  0.095  0.507  1.0
  Ce  Ce3  1  0.213  0.539  0.138  1.0
  Se  Se4  1  0.812  0.220  0.642  1.0
  Se  Se5  1  0.724  0.898  0.966  1.0
  Se  Se6  1  0.495  0.850  0.296  1.0
  Se  Se7  1  0.158  0.872  0.599  1.0
  Se  Se8  1  0.831  0.424  0.133  1.0
  Se  Se9  1  0.201  0.804  0.961  1.0
  Se  Se10  1  0.310  0.315  0.928  1.0
  Se  Se11  1  0.369  0.306  0.306  1.0
[/CIF]
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The 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(2), one Se(3), one Se(5), one Se(6), one Se(7), and one Se(8) atom to form distorted CeSe6 octahedra that share  a cornercorner with one Ce(2)Se5 trigonal bipyramid,  a cornercorner with one Ce(4)Se5 trigonal bipyramid,  an edgeedge with one Ce(2)Se5 trigonal bipyramid, edges with two equivalent Ce(4)Se5 trigonal bipyramids, and  an edgeedge with one Ce(3)Se4 trigonal pyramid. In the second Ce site, Ce(2) is bonded to one Se(1), one Se(2), one Se(4), one Se(6), and one Se(7) atom to form CeSe5 trigonal bipyramids that share  a cornercorner with one Ce(1)Se6 octahedra, corners with two equivalent Ce(4)Se5 trigonal bipyramids, corners with two equivalent Ce(3)Se4 trigonal pyramids, and  an edgeedge with one Ce(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 53°. In the third Ce site, Ce(3) is bonded to one Se(1), one Se(3), one Se(4), and one Se(8) atom to form CeSe4 trigonal pyramids that share corners with two equivalent Ce(2)Se5 trigonal bipyramids, corners with two equivalent Ce(4)Se5 trigonal bipyramids, and  an edgeedge with one Ce(1)Se6 octahedra. In the fourth Ce site, Ce(4) is bonded to one Se(3), one Se(5), one Se(6), one Se(7), and one Se(8) atom to form CeSe5 trigonal bipyramids that share  a cornercorner with one Ce(1)Se6 octahedra, corners with two equivalent Ce(2)Se5 trigonal bipyramids, corners with two equivalent Ce(3)Se4 trigonal pyramids, and edges with two equivalent Ce(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 36°. There are eight inequivalent Se sites. In the first Se site, Se(1) is bonded in a bent 120 degrees geometry to one Ce(2) and one Ce(3) atom. In the second Se site, Se(2) is bonded in a bent 120 degrees geometry to one Ce(1) and one Ce(2) atom. In the third Se site, Se(3) is bonded in a distorted T-shaped geometry to one Ce(1), one Ce(3), and one Ce(4) atom. In the fourth Se site, Se(4) is bonded in a bent 120 degrees geometry to one Ce(2) and one Ce(3) atom. In the fifth Se site, Se(5) is bonded in a bent 150 degrees geometry to one Ce(1) 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(2), and one Ce(4) atom. In the seventh Se site, Se(7) is bonded in a trigonal non-coplanar geometry to one Ce(1), one Ce(2), and one Ce(4) atom. In the eighth Se site, Se(8) is bonded in a T-shaped geometry to one Ce(1), 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   7.289
_cell_length_b   7.491
_cell_length_c   10.102
_cell_angle_alpha   95.434
_cell_angle_beta   96.919
_cell_angle_gamma   104.388
_symmetry_Int_Tables_number   1
_cell_volume   525.911
_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  0.517  0.107  0.093  1.0
  Ce  Ce1  1  0.995  0.016  0.808  1.0
  Ce  Ce2  1  0.451  0.095  0.507  1.0
  Ce  Ce3  1  0.213  0.539  0.138  1.0
  Se  Se4  1  0.812  0.220  0.642  1.0
  Se  Se5  1  0.724  0.898  0.966  1.0
  Se  Se6  1  0.495  0.850  0.296  1.0
  Se  Se7  1  0.158  0.872  0.599  1.0
  Se  Se8  1  0.831  0.424  0.133  1.0
  Se  Se9  1  0.201  0.804  0.961  1.0
  Se  Se10  1  0.310  0.315  0.928  1.0
  Se  Se11  1  0.369  0.306  0.306  1.0
[/CIF]
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