The material structure described by Nb9TlSe12 crystallizes in the trigonal R-3 space group. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one Se(2), one Se(4), two equivalent Se(1), and two equivalent Se(3) atoms. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one Se(2), one Se(4), two equivalent Se(1), and two equivalent Se(3) atoms. In the third Nb site, Nb(3) is bonded in a 6-coordinate geometry to two equivalent Se(1), two equivalent Se(2), and two equivalent Se(4) atoms. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a distorted hexagonal planar geometry to six equivalent Se(2) atoms. In the second Tl site, Tl(2) is bonded in a distorted hexagonal planar geometry to six equivalent Se(3) atoms. There are four inequivalent Se sites. In the first Se site, Se(2) is bonded in a 5-coordinate geometry to one Nb(1), one Nb(2), two equivalent Nb(3), and one Tl(1) atom. In the second Se site, Se(3) is bonded in a 5-coordinate geometry to two equivalent Nb(1), two equivalent Nb(2), and one Tl(2) atom. In the third Se site, Se(4) is bonded in a 4-coordinate geometry to one Nb(1), one Nb(2), and two equivalent Nb(3) atoms. In the fourth Se site, Se(1) is bonded to two equivalent Nb(1), two equivalent Nb(2), and two equivalent Nb(3) atoms to form distorted face-sharing SeNb6 pentagonal pyramids. is represented by the CIF file [CIF]
data_Nb9TlSe12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.769
_cell_length_b   10.769
_cell_length_c   10.769
_cell_angle_alpha   109.958
_cell_angle_beta   109.958
_cell_angle_gamma   109.958
_symmetry_Int_Tables_number   1
_cell_volume   943.783
_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
  Nb  Nb0  1  0.659  0.552  0.040  1.0
  Nb  Nb1  1  0.325  0.218  0.706  1.0
  Nb  Nb2  1  0.991  0.885  0.373  1.0
  Nb  Nb3  1  0.885  0.373  0.991  1.0
  Nb  Nb4  1  0.552  0.040  0.659  1.0
  Nb  Nb5  1  0.218  0.706  0.325  1.0
  Nb  Nb6  1  0.706  0.325  0.218  1.0
  Nb  Nb7  1  0.373  0.991  0.885  1.0
  Nb  Nb8  1  0.040  0.659  0.552  1.0
  Nb  Nb9  1  0.675  0.782  0.294  1.0
  Nb  Nb10  1  0.341  0.448  0.960  1.0
  Nb  Nb11  1  0.009  0.115  0.627  1.0
  Nb  Nb12  1  0.448  0.960  0.341  1.0
  Nb  Nb13  1  0.115  0.627  0.009  1.0
  Nb  Nb14  1  0.782  0.294  0.675  1.0
  Nb  Nb15  1  0.627  0.009  0.115  1.0
  Nb  Nb16  1  0.294  0.675  0.782  1.0
  Nb  Nb17  1  0.960  0.341  0.448  1.0
  Tl  Tl18  1  0.000  0.000  0.000  1.0
  Tl  Tl19  1  0.500  0.500  0.500  1.0
  Se  Se20  1  0.083  0.416  0.750  1.0
  Se  Se21  1  0.416  0.750  0.083  1.0
  Se  Se22  1  0.750  0.083  0.416  1.0
  Se  Se23  1  0.917  0.584  0.250  1.0
  Se  Se24  1  0.250  0.917  0.584  1.0
  Se  Se25  1  0.584  0.250  0.917  1.0
  Se  Se26  1  0.158  0.876  0.218  1.0
  Se  Se27  1  0.490  0.208  0.550  1.0
  Se  Se28  1  0.824  0.543  0.883  1.0
  Se  Se29  1  0.208  0.550  0.490  1.0
  Se  Se30  1  0.543  0.883  0.824  1.0
  Se  Se31  1  0.876  0.218  0.158  1.0
  Se  Se32  1  0.883  0.824  0.543  1.0
  Se  Se33  1  0.218  0.158  0.876  1.0
  Se  Se34  1  0.550  0.490  0.208  1.0
  Se  Se35  1  0.842  0.124  0.782  1.0
  Se  Se36  1  0.176  0.457  0.117  1.0
  Se  Se37  1  0.510  0.792  0.450  1.0
  Se  Se38  1  0.792  0.450  0.510  1.0
  Se  Se39  1  0.124  0.782  0.842  1.0
  Se  Se40  1  0.457  0.117  0.176  1.0
  Se  Se41  1  0.117  0.176  0.457  1.0
  Se  Se42  1  0.450  0.510  0.792  1.0
  Se  Se43  1  0.782  0.842  0.124  1.0
[/CIF]
.
The material structure described by Nb9TlSe12 crystallizes in the trigonal R-3 space group. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one Se(2), one Se(4), two equivalent Se(1), and two equivalent Se(3) atoms. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one Se(2), one Se(4), two equivalent Se(1), and two equivalent Se(3) atoms. In the third Nb site, Nb(3) is bonded in a 6-coordinate geometry to two equivalent Se(1), two equivalent Se(2), and two equivalent Se(4) atoms. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a distorted hexagonal planar geometry to six equivalent Se(2) atoms. In the second Tl site, Tl(2) is bonded in a distorted hexagonal planar geometry to six equivalent Se(3) atoms. There are four inequivalent Se sites. In the first Se site, Se(2) is bonded in a 5-coordinate geometry to one Nb(1), one Nb(2), two equivalent Nb(3), and one Tl(1) atom. In the second Se site, Se(3) is bonded in a 5-coordinate geometry to two equivalent Nb(1), two equivalent Nb(2), and one Tl(2) atom. In the third Se site, Se(4) is bonded in a 4-coordinate geometry to one Nb(1), one Nb(2), and two equivalent Nb(3) atoms. In the fourth Se site, Se(1) is bonded to two equivalent Nb(1), two equivalent Nb(2), and two equivalent Nb(3) atoms to form distorted face-sharing SeNb6 pentagonal pyramids. is represented by the CIF file [CIF]
data_Nb9TlSe12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.769
_cell_length_b   10.769
_cell_length_c   10.769
_cell_angle_alpha   109.958
_cell_angle_beta   109.958
_cell_angle_gamma   109.958
_symmetry_Int_Tables_number   1
_cell_volume   943.783
_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
  Nb  Nb0  1  0.659  0.552  0.040  1.0
  Nb  Nb1  1  0.325  0.218  0.706  1.0
  Nb  Nb2  1  0.991  0.885  0.373  1.0
  Nb  Nb3  1  0.885  0.373  0.991  1.0
  Nb  Nb4  1  0.552  0.040  0.659  1.0
  Nb  Nb5  1  0.218  0.706  0.325  1.0
  Nb  Nb6  1  0.706  0.325  0.218  1.0
  Nb  Nb7  1  0.373  0.991  0.885  1.0
  Nb  Nb8  1  0.040  0.659  0.552  1.0
  Nb  Nb9  1  0.675  0.782  0.294  1.0
  Nb  Nb10  1  0.341  0.448  0.960  1.0
  Nb  Nb11  1  0.009  0.115  0.627  1.0
  Nb  Nb12  1  0.448  0.960  0.341  1.0
  Nb  Nb13  1  0.115  0.627  0.009  1.0
  Nb  Nb14  1  0.782  0.294  0.675  1.0
  Nb  Nb15  1  0.627  0.009  0.115  1.0
  Nb  Nb16  1  0.294  0.675  0.782  1.0
  Nb  Nb17  1  0.960  0.341  0.448  1.0
  Tl  Tl18  1  0.000  0.000  0.000  1.0
  Tl  Tl19  1  0.500  0.500  0.500  1.0
  Se  Se20  1  0.083  0.416  0.750  1.0
  Se  Se21  1  0.416  0.750  0.083  1.0
  Se  Se22  1  0.750  0.083  0.416  1.0
  Se  Se23  1  0.917  0.584  0.250  1.0
  Se  Se24  1  0.250  0.917  0.584  1.0
  Se  Se25  1  0.584  0.250  0.917  1.0
  Se  Se26  1  0.158  0.876  0.218  1.0
  Se  Se27  1  0.490  0.208  0.550  1.0
  Se  Se28  1  0.824  0.543  0.883  1.0
  Se  Se29  1  0.208  0.550  0.490  1.0
  Se  Se30  1  0.543  0.883  0.824  1.0
  Se  Se31  1  0.876  0.218  0.158  1.0
  Se  Se32  1  0.883  0.824  0.543  1.0
  Se  Se33  1  0.218  0.158  0.876  1.0
  Se  Se34  1  0.550  0.490  0.208  1.0
  Se  Se35  1  0.842  0.124  0.782  1.0
  Se  Se36  1  0.176  0.457  0.117  1.0
  Se  Se37  1  0.510  0.792  0.450  1.0
  Se  Se38  1  0.792  0.450  0.510  1.0
  Se  Se39  1  0.124  0.782  0.842  1.0
  Se  Se40  1  0.457  0.117  0.176  1.0
  Se  Se41  1  0.117  0.176  0.457  1.0
  Se  Se42  1  0.450  0.510  0.792  1.0
  Se  Se43  1  0.782  0.842  0.124  1.0
[/CIF]
.