data_CeBi2SeO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.9
_cell_length_b   3.9
_cell_length_c   8.96
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CeBi2SeO4
_chemical_formula_sum   'Ce1 Bi2 Se1 O4'
_cell_volume   136.26
_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  0.0  0.0  0.48  1.0
  Bi  Bi1  1  0.95  0.95  0.12  1.0
  Bi  Bi2  1  0.95  0.95  0.84  1.0
  Se  Se3  1  0.0  0.0  0.0  1.0
  O  O4  1  0.0  0.95  0.85  1.0
  O  O5  1  0.0  0.95  0.11  1.0
  O  O6  1  0.95  0.0  0.85  1.0
  O  O7  1  0.95  0.0  0.11  1.0

data_CeBi2SeO4
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.52
_cell_length_b   5.52
_cell_length_c   8.96
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   CeBi2SeO4
_chemical_formula_sum   'Ce2 Bi4 Se2 O8'
_cell_volume   272.53
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  2  0.0  0.0  0.48  1.0
  Bi  Bi1  2  0.45  0.5  0.12  1.0
  Bi  Bi2  2  0.45  0.5  0.84  1.0
  Se  Se3  2  0.0  0.0  0.0  1.0
  O  O4  4  0.48  0.48  0.11  1.0
  O  O5  4  0.48  0.48  0.85  1.0

Ce Bi Bi Se O O O O
CeBi2SeO4 crystallizes in the monoclinic Cm space group. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a distorted q4 geometry to four equivalent Ce(1), one Bi(1), one Bi(2), two equivalent O(1), and two equivalent O(2) atoms. All Ce(1)-Ce(1) bond lengths are 3.90 Å. The Ce(1)-Bi(1) bond length is 3.25 Å. The Ce(1)-Bi(2) bond length is 3.25 Å. Both Ce(1)-O(1) bond lengths are 3.30 Å. Both Ce(1)-O(2) bond lengths are 3.30 Å. In the second Ce site, Ce(1) is bonded in a distorted q4 geometry to four equivalent Ce(1), one Bi(1), one Bi(2), two equivalent O(1), and two equivalent O(2) atoms. The Ce(1)-Bi(1) bond length is 3.25 Å. The Ce(1)-Bi(2) bond length is 3.25 Å. Both Ce(1)-O(1) bond lengths are 3.30 Å. Both Ce(1)-O(2) bond lengths are 3.30 Å. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in an L-shaped geometry to one Ce(1) and two equivalent O(2) atoms. Both Bi(1)-O(2) bond lengths are 0.20 Å. In the second Bi site, Bi(2) is bonded in an L-shaped geometry to one Ce(1) and two equivalent O(1) atoms. Both Bi(2)-O(1) bond lengths are 0.20 Å. Se(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(2) atoms. Both Se(1)-O(1) bond lengths are 1.39 Å. Both Se(1)-O(2) bond lengths are 1.02 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one Ce(1), one Bi(2), and one Se(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to one Ce(1), one Bi(1), and one Se(1) atom.