The compound described by Bi2Se crystallizes in the trigonal P-3m1 space group. There are four inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to three equivalent Bi(1) and three equivalent Se(2) atoms to form distorted BiBi3Se3 octahedra that share corners with three equivalent Bi(2)Se6 octahedra, edges with three equivalent Bi(2)Se6 octahedra, and edges with six equivalent Bi(1)Bi3Se3 octahedra. The corner-sharing octahedral tilt angles are 11°. In the second Bi site, Bi(2) is bonded to three equivalent Se(1) and three equivalent Se(2) atoms to form BiSe6 octahedra that share corners with three equivalent Bi(1)Bi3Se3 octahedra, corners with three equivalent Bi(4)Bi3Se3 octahedra, edges with three equivalent Bi(1)Bi3Se3 octahedra, edges with three equivalent Bi(4)Bi3Se3 octahedra, and edges with six equivalent Bi(2)Se6 octahedra. The corner-sharing octahedral tilt angles range from 8-11°. In the third Bi site, Bi(3) is bonded to three equivalent Bi(3) and three equivalent Bi(4) atoms to form distorted BiBi6 octahedra that share corners with three equivalent Bi(4)Bi3Se3 octahedra, corners with three equivalent Se(1)Bi6 octahedra, edges with three equivalent Bi(4)Bi3Se3 octahedra, edges with three equivalent Se(1)Bi6 octahedra, and edges with six equivalent Bi(3)Bi6 octahedra. The corner-sharing octahedral tilt angles range from 6-11°. In the fourth Bi site, Bi(4) is bonded to three equivalent Bi(3) and three equivalent Se(1) atoms to form BiBi3Se3 octahedra that share corners with three equivalent Bi(3)Bi6 octahedra, corners with three equivalent Bi(2)Se6 octahedra, edges with three equivalent Bi(3)Bi6 octahedra, edges with three equivalent Bi(2)Se6 octahedra, and edges with six equivalent Bi(4)Bi3Se3 octahedra. The corner-sharing octahedral tilt angles range from 8-11°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to three equivalent Bi(2) and three equivalent Bi(4) atoms to form distorted SeBi6 octahedra that share corners with three equivalent Bi(3)Bi6 octahedra, edges with three equivalent Bi(3)Bi6 octahedra, and edges with six equivalent Se(1)Bi6 octahedra. The corner-sharing octahedral tilt angles are 6°. In the second Se site, Se(2) is bonded in a 3-coordinate geometry to three equivalent Bi(1) and three equivalent Bi(2) atoms. is represented by the CIF card [CIF]
data_Bi2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.246
_cell_length_b   4.246
_cell_length_c   24.329
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   379.811
_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
  Bi  Bi0  1  0.667  0.333  0.462  1.0
  Bi  Bi1  1  0.333  0.667  0.538  1.0
  Bi  Bi2  1  0.667  0.333  0.705  1.0
  Bi  Bi3  1  0.333  0.667  0.295  1.0
  Bi  Bi4  1  0.667  0.333  0.945  1.0
  Bi  Bi5  1  0.333  0.667  0.055  1.0
  Bi  Bi6  1  0.000  0.000  0.869  1.0
  Bi  Bi7  1  0.000  0.000  0.131  1.0
  Se  Se8  1  0.667  0.333  0.225  1.0
  Se  Se9  1  0.333  0.667  0.775  1.0
  Se  Se10  1  0.000  0.000  0.637  1.0
  Se  Se11  1  0.000  0.000  0.363  1.0
[/CIF]
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The compound described by Bi2Se crystallizes in the trigonal P-3m1 space group. There are four inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to three equivalent Bi(1) and three equivalent Se(2) atoms to form distorted BiBi3Se3 octahedra that share corners with three equivalent Bi(2)Se6 octahedra, edges with three equivalent Bi(2)Se6 octahedra, and edges with six equivalent Bi(1)Bi3Se3 octahedra. The corner-sharing octahedral tilt angles are 11°. In the second Bi site, Bi(2) is bonded to three equivalent Se(1) and three equivalent Se(2) atoms to form BiSe6 octahedra that share corners with three equivalent Bi(1)Bi3Se3 octahedra, corners with three equivalent Bi(4)Bi3Se3 octahedra, edges with three equivalent Bi(1)Bi3Se3 octahedra, edges with three equivalent Bi(4)Bi3Se3 octahedra, and edges with six equivalent Bi(2)Se6 octahedra. The corner-sharing octahedral tilt angles range from 8-11°. In the third Bi site, Bi(3) is bonded to three equivalent Bi(3) and three equivalent Bi(4) atoms to form distorted BiBi6 octahedra that share corners with three equivalent Bi(4)Bi3Se3 octahedra, corners with three equivalent Se(1)Bi6 octahedra, edges with three equivalent Bi(4)Bi3Se3 octahedra, edges with three equivalent Se(1)Bi6 octahedra, and edges with six equivalent Bi(3)Bi6 octahedra. The corner-sharing octahedral tilt angles range from 6-11°. In the fourth Bi site, Bi(4) is bonded to three equivalent Bi(3) and three equivalent Se(1) atoms to form BiBi3Se3 octahedra that share corners with three equivalent Bi(3)Bi6 octahedra, corners with three equivalent Bi(2)Se6 octahedra, edges with three equivalent Bi(3)Bi6 octahedra, edges with three equivalent Bi(2)Se6 octahedra, and edges with six equivalent Bi(4)Bi3Se3 octahedra. The corner-sharing octahedral tilt angles range from 8-11°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to three equivalent Bi(2) and three equivalent Bi(4) atoms to form distorted SeBi6 octahedra that share corners with three equivalent Bi(3)Bi6 octahedra, edges with three equivalent Bi(3)Bi6 octahedra, and edges with six equivalent Se(1)Bi6 octahedra. The corner-sharing octahedral tilt angles are 6°. In the second Se site, Se(2) is bonded in a 3-coordinate geometry to three equivalent Bi(1) and three equivalent Bi(2) atoms. is represented by the CIF card [CIF]
data_Bi2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.246
_cell_length_b   4.246
_cell_length_c   24.329
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   379.811
_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
  Bi  Bi0  1  0.667  0.333  0.462  1.0
  Bi  Bi1  1  0.333  0.667  0.538  1.0
  Bi  Bi2  1  0.667  0.333  0.705  1.0
  Bi  Bi3  1  0.333  0.667  0.295  1.0
  Bi  Bi4  1  0.667  0.333  0.945  1.0
  Bi  Bi5  1  0.333  0.667  0.055  1.0
  Bi  Bi6  1  0.000  0.000  0.869  1.0
  Bi  Bi7  1  0.000  0.000  0.131  1.0
  Se  Se8  1  0.667  0.333  0.225  1.0
  Se  Se9  1  0.333  0.667  0.775  1.0
  Se  Se10  1  0.000  0.000  0.637  1.0
  Se  Se11  1  0.000  0.000  0.363  1.0
[/CIF]
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