The material described by Ce2SeF4 crystallizes in the trigonal R-3m space group. Ce(1) is bonded in a 10-coordinate geometry to three equivalent Se(1), three equivalent F(2), and four equivalent F(1) atoms. Se(1) is bonded to six equivalent Ce(1) atoms to form SeCe6 octahedra that share corners with eighteen equivalent F(1)Ce4 tetrahedra, edges with six equivalent Se(1)Ce6 octahedra, and faces with two equivalent F(1)Ce4 tetrahedra. There are two inequivalent F sites. In the first F site, F(1) is bonded to four equivalent Ce(1) atoms to form FCe4 tetrahedra that share corners with nine equivalent Se(1)Ce6 octahedra, corners with six equivalent F(1)Ce4 tetrahedra, edges with three equivalent F(1)Ce4 tetrahedra, and  a faceface with one Se(1)Ce6 octahedra. The corner-sharing octahedral tilt angles range from 49-52°. In the second F site, F(2) is bonded in a trigonal planar geometry to three equivalent Ce(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ce2SeF4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.029
_cell_length_b   8.029
_cell_length_c   8.029
_cell_angle_alpha   29.866
_cell_angle_beta   29.866
_cell_angle_gamma   29.866
_symmetry_Int_Tables_number   1
_cell_volume   113.652
_cell_formula_units_Z   1
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  0.757  0.757  0.757  1.0
  Ce  Ce1  1  0.243  0.243  0.243  1.0
  Se  Se2  1  0.000  0.000  0.000  1.0
  F  F3  1  0.861  0.861  0.861  1.0
  F  F4  1  0.139  0.139  0.139  1.0
  F  F5  1  0.569  0.569  0.569  1.0
  F  F6  1  0.431  0.431  0.431  1.0
[/CIF]
.
The material described by Ce2SeF4 crystallizes in the trigonal R-3m space group. Ce(1) is bonded in a 10-coordinate geometry to three equivalent Se(1), three equivalent F(2), and four equivalent F(1) atoms. Se(1) is bonded to six equivalent Ce(1) atoms to form SeCe6 octahedra that share corners with eighteen equivalent F(1)Ce4 tetrahedra, edges with six equivalent Se(1)Ce6 octahedra, and faces with two equivalent F(1)Ce4 tetrahedra. There are two inequivalent F sites. In the first F site, F(1) is bonded to four equivalent Ce(1) atoms to form FCe4 tetrahedra that share corners with nine equivalent Se(1)Ce6 octahedra, corners with six equivalent F(1)Ce4 tetrahedra, edges with three equivalent F(1)Ce4 tetrahedra, and  a faceface with one Se(1)Ce6 octahedra. The corner-sharing octahedral tilt angles range from 49-52°. In the second F site, F(2) is bonded in a trigonal planar geometry to three equivalent Ce(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ce2SeF4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.029
_cell_length_b   8.029
_cell_length_c   8.029
_cell_angle_alpha   29.866
_cell_angle_beta   29.866
_cell_angle_gamma   29.866
_symmetry_Int_Tables_number   1
_cell_volume   113.652
_cell_formula_units_Z   1
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  0.757  0.757  0.757  1.0
  Ce  Ce1  1  0.243  0.243  0.243  1.0
  Se  Se2  1  0.000  0.000  0.000  1.0
  F  F3  1  0.861  0.861  0.861  1.0
  F  F4  1  0.139  0.139  0.139  1.0
  F  F5  1  0.569  0.569  0.569  1.0
  F  F6  1  0.431  0.431  0.431  1.0
[/CIF]
.