The crystal structure described by Bi4N2Se3 crystallizes in the orthorhombic Pnnm space group. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 6-coordinate geometry to two equivalent N(1), two equivalent Se(1), and two equivalent Se(2) atoms. In the second Bi site, Bi(2) is bonded in a 6-coordinate geometry to two equivalent N(1), one Se(1), and three equivalent Se(2) atoms. N(1) is bonded to two equivalent Bi(1) and two equivalent Bi(2) atoms to form NBi4 tetrahedra that share corners with two equivalent Se(1)Bi6 octahedra, corners with two equivalent N(1)Bi4 tetrahedra, corners with four equivalent Se(2)Bi5 trigonal bipyramids, edges with two equivalent Se(1)Bi6 octahedra,  an edgeedge with one N(1)Bi4 tetrahedra, and edges with three equivalent Se(2)Bi5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 45°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Bi(2) and four equivalent Bi(1) atoms to form SeBi6 octahedra that share corners with four equivalent N(1)Bi4 tetrahedra, corners with ten equivalent Se(2)Bi5 trigonal bipyramids, edges with two equivalent Se(1)Bi6 octahedra, edges with four equivalent N(1)Bi4 tetrahedra, and edges with two equivalent Se(2)Bi5 trigonal bipyramids. In the second Se site, Se(2) is bonded to two equivalent Bi(1) and three equivalent Bi(2) atoms to form distorted SeBi5 trigonal bipyramids that share corners with five equivalent Se(1)Bi6 octahedra, corners with four equivalent N(1)Bi4 tetrahedra, corners with four equivalent Se(2)Bi5 trigonal bipyramids,  an edgeedge with one Se(1)Bi6 octahedra, edges with three equivalent N(1)Bi4 tetrahedra, and edges with two equivalent Se(2)Bi5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 28-70°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Bi4Se3N2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.182
_cell_length_b   15.760
_cell_length_c   4.034
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   456.662
_cell_formula_units_Z   2
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  0.705  0.934  0.500  1.0
  Bi  Bi1  1  0.295  0.066  0.500  1.0
  Bi  Bi2  1  0.205  0.566  0.000  1.0
  Bi  Bi3  1  0.795  0.434  0.000  1.0
  Bi  Bi4  1  0.782  0.647  0.500  1.0
  Bi  Bi5  1  0.218  0.353  0.500  1.0
  Bi  Bi6  1  0.282  0.853  0.000  1.0
  Bi  Bi7  1  0.718  0.147  0.000  1.0
  Se  Se8  1  0.500  0.500  0.500  1.0
  Se  Se9  1  0.000  0.000  0.000  1.0
  Se  Se10  1  0.848  0.288  0.500  1.0
  Se  Se11  1  0.152  0.712  0.500  1.0
  Se  Se12  1  0.348  0.212  0.000  1.0
  Se  Se13  1  0.652  0.788  0.000  1.0
  N  N14  1  0.616  0.076  0.500  1.0
  N  N15  1  0.384  0.924  0.500  1.0
  N  N16  1  0.116  0.424  0.000  1.0
  N  N17  1  0.884  0.576  0.000  1.0
[/CIF]
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The crystal structure described by Bi4N2Se3 crystallizes in the orthorhombic Pnnm space group. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 6-coordinate geometry to two equivalent N(1), two equivalent Se(1), and two equivalent Se(2) atoms. In the second Bi site, Bi(2) is bonded in a 6-coordinate geometry to two equivalent N(1), one Se(1), and three equivalent Se(2) atoms. N(1) is bonded to two equivalent Bi(1) and two equivalent Bi(2) atoms to form NBi4 tetrahedra that share corners with two equivalent Se(1)Bi6 octahedra, corners with two equivalent N(1)Bi4 tetrahedra, corners with four equivalent Se(2)Bi5 trigonal bipyramids, edges with two equivalent Se(1)Bi6 octahedra,  an edgeedge with one N(1)Bi4 tetrahedra, and edges with three equivalent Se(2)Bi5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 45°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Bi(2) and four equivalent Bi(1) atoms to form SeBi6 octahedra that share corners with four equivalent N(1)Bi4 tetrahedra, corners with ten equivalent Se(2)Bi5 trigonal bipyramids, edges with two equivalent Se(1)Bi6 octahedra, edges with four equivalent N(1)Bi4 tetrahedra, and edges with two equivalent Se(2)Bi5 trigonal bipyramids. In the second Se site, Se(2) is bonded to two equivalent Bi(1) and three equivalent Bi(2) atoms to form distorted SeBi5 trigonal bipyramids that share corners with five equivalent Se(1)Bi6 octahedra, corners with four equivalent N(1)Bi4 tetrahedra, corners with four equivalent Se(2)Bi5 trigonal bipyramids,  an edgeedge with one Se(1)Bi6 octahedra, edges with three equivalent N(1)Bi4 tetrahedra, and edges with two equivalent Se(2)Bi5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 28-70°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Bi4Se3N2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.182
_cell_length_b   15.760
_cell_length_c   4.034
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   456.662
_cell_formula_units_Z   2
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  0.705  0.934  0.500  1.0
  Bi  Bi1  1  0.295  0.066  0.500  1.0
  Bi  Bi2  1  0.205  0.566  0.000  1.0
  Bi  Bi3  1  0.795  0.434  0.000  1.0
  Bi  Bi4  1  0.782  0.647  0.500  1.0
  Bi  Bi5  1  0.218  0.353  0.500  1.0
  Bi  Bi6  1  0.282  0.853  0.000  1.0
  Bi  Bi7  1  0.718  0.147  0.000  1.0
  Se  Se8  1  0.500  0.500  0.500  1.0
  Se  Se9  1  0.000  0.000  0.000  1.0
  Se  Se10  1  0.848  0.288  0.500  1.0
  Se  Se11  1  0.152  0.712  0.500  1.0
  Se  Se12  1  0.348  0.212  0.000  1.0
  Se  Se13  1  0.652  0.788  0.000  1.0
  N  N14  1  0.616  0.076  0.500  1.0
  N  N15  1  0.384  0.924  0.500  1.0
  N  N16  1  0.116  0.424  0.000  1.0
  N  N17  1  0.884  0.576  0.000  1.0
[/CIF]
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