The material described by Nb5PbSe8 crystallizes in the monoclinic C2/m space group. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form a mixture of distorted corner and edge-sharing NbSe6 octahedra. The corner-sharing octahedral tilt angles are 49°. In the second Nb site, Nb(2) is bonded to one Se(1), two equivalent Se(2), and three equivalent Se(4) atoms to form a mixture of distorted face, corner, and edge-sharing NbSe6 octahedra. The corner-sharing octahedral tilt angles range from 50-53°. In the third Nb site, Nb(3) is bonded to one Se(1), two equivalent Se(4), and three equivalent Se(3) atoms to form a mixture of distorted face, corner, and edge-sharing NbSe6 octahedra. The corner-sharing octahedral tilt angles range from 49-53°. Pb(1) is bonded in a 12-coordinate geometry to two equivalent Pb(1), two equivalent Se(1), four equivalent Se(2), and four equivalent Se(3) atoms. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 4-coordinate geometry to one Nb(2), one Nb(3), two equivalent Nb(1), and one Pb(1) atom. In the second Se site, Se(2) is bonded in a 3-coordinate geometry to one Nb(1), two equivalent Nb(2), and two equivalent Pb(1) atoms. In the third Se site, Se(3) is bonded in a 3-coordinate geometry to three equivalent Nb(3) and two equivalent Pb(1) atoms. In the fourth Se site, Se(4) is bonded in a 5-coordinate geometry to two equivalent Nb(3) and three equivalent Nb(2) atoms. is represented by the CIF file [CIF]
data_Nb5PbSe8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.421
_cell_length_b   9.421
_cell_length_c   9.436
_cell_angle_alpha   77.004
_cell_angle_beta   77.004
_cell_angle_gamma   21.449
_symmetry_Int_Tables_number   1
_cell_volume   298.148
_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
  Nb  Nb0  1  0.000  0.000  0.000  1.0
  Nb  Nb1  1  0.359  0.359  0.997  1.0
  Nb  Nb2  1  0.641  0.641  0.003  1.0
  Nb  Nb3  1  0.289  0.289  0.368  1.0
  Nb  Nb4  1  0.711  0.711  0.632  1.0
  Pb  Pb5  1  0.500  0.500  0.500  1.0
  Se  Se6  1  0.570  0.570  0.801  1.0
  Se  Se7  1  0.430  0.430  0.199  1.0
  Se  Se8  1  0.085  0.085  0.193  1.0
  Se  Se9  1  0.915  0.915  0.807  1.0
  Se  Se10  1  0.150  0.150  0.491  1.0
  Se  Se11  1  0.850  0.850  0.509  1.0
  Se  Se12  1  0.239  0.239  0.839  1.0
  Se  Se13  1  0.761  0.761  0.161  1.0
[/CIF]
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The material described by Nb5PbSe8 crystallizes in the monoclinic C2/m space group. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form a mixture of distorted corner and edge-sharing NbSe6 octahedra. The corner-sharing octahedral tilt angles are 49°. In the second Nb site, Nb(2) is bonded to one Se(1), two equivalent Se(2), and three equivalent Se(4) atoms to form a mixture of distorted face, corner, and edge-sharing NbSe6 octahedra. The corner-sharing octahedral tilt angles range from 50-53°. In the third Nb site, Nb(3) is bonded to one Se(1), two equivalent Se(4), and three equivalent Se(3) atoms to form a mixture of distorted face, corner, and edge-sharing NbSe6 octahedra. The corner-sharing octahedral tilt angles range from 49-53°. Pb(1) is bonded in a 12-coordinate geometry to two equivalent Pb(1), two equivalent Se(1), four equivalent Se(2), and four equivalent Se(3) atoms. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 4-coordinate geometry to one Nb(2), one Nb(3), two equivalent Nb(1), and one Pb(1) atom. In the second Se site, Se(2) is bonded in a 3-coordinate geometry to one Nb(1), two equivalent Nb(2), and two equivalent Pb(1) atoms. In the third Se site, Se(3) is bonded in a 3-coordinate geometry to three equivalent Nb(3) and two equivalent Pb(1) atoms. In the fourth Se site, Se(4) is bonded in a 5-coordinate geometry to two equivalent Nb(3) and three equivalent Nb(2) atoms. is represented by the CIF file [CIF]
data_Nb5PbSe8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.421
_cell_length_b   9.421
_cell_length_c   9.436
_cell_angle_alpha   77.004
_cell_angle_beta   77.004
_cell_angle_gamma   21.449
_symmetry_Int_Tables_number   1
_cell_volume   298.148
_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
  Nb  Nb0  1  0.000  0.000  0.000  1.0
  Nb  Nb1  1  0.359  0.359  0.997  1.0
  Nb  Nb2  1  0.641  0.641  0.003  1.0
  Nb  Nb3  1  0.289  0.289  0.368  1.0
  Nb  Nb4  1  0.711  0.711  0.632  1.0
  Pb  Pb5  1  0.500  0.500  0.500  1.0
  Se  Se6  1  0.570  0.570  0.801  1.0
  Se  Se7  1  0.430  0.430  0.199  1.0
  Se  Se8  1  0.085  0.085  0.193  1.0
  Se  Se9  1  0.915  0.915  0.807  1.0
  Se  Se10  1  0.150  0.150  0.491  1.0
  Se  Se11  1  0.850  0.850  0.509  1.0
  Se  Se12  1  0.239  0.239  0.839  1.0
  Se  Se13  1  0.761  0.761  0.161  1.0
[/CIF]
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