The compound described by Nb12TlTe16 crystallizes in the monoclinic Cm space group. There are nine inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one Te(5), one Te(9), two equivalent Te(10), and two equivalent Te(3) atoms. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one Te(4), one Te(8), two equivalent Te(10), and two equivalent Te(3) atoms. In the third Nb site, Nb(3) is bonded in a 6-coordinate geometry to one Te(5), one Te(7), two equivalent Te(11), and two equivalent Te(3) atoms. In the fourth Nb site, Nb(4) is bonded in a 6-coordinate geometry to one Te(4), one Te(6), two equivalent Te(11), and two equivalent Te(3) atoms. In the fifth Nb site, Nb(5) is bonded in a 6-coordinate geometry to one Te(7), one Te(9), two equivalent Te(12), and two equivalent Te(3) atoms. In the sixth Nb site, Nb(6) is bonded in a 6-coordinate geometry to one Te(6), one Te(8), two equivalent Te(12), and two equivalent Te(3) atoms. In the seventh Nb site, Nb(7) is bonded in a 6-coordinate geometry to one Te(1), one Te(10), one Te(12), one Te(2), one Te(4), and one Te(5) atom. In the eighth Nb site, Nb(8) is bonded in a 6-coordinate geometry to one Te(1), one Te(10), one Te(11), one Te(2), one Te(6), and one Te(7) atom. In the ninth Nb site, Nb(9) is bonded in a 6-coordinate geometry to one Te(1), one Te(11), one Te(12), one Te(2), one Te(8), and one Te(9) atom. Tl(1) is bonded in a trigonal planar geometry to one Te(5), one Te(7), and one Te(8) atom. There are twelve inequivalent Te sites. In the first Te site, Te(1) is bonded to two equivalent Nb(7), two equivalent Nb(8), and two equivalent Nb(9) atoms to form distorted face-sharing TeNb6 pentagonal pyramids. In the second Te site, Te(2) is bonded to two equivalent Nb(7), two equivalent Nb(8), and two equivalent Nb(9) atoms to form distorted face-sharing TeNb6 pentagonal pyramids. In the third Te site, Te(3) is bonded to one Nb(1), one Nb(2), one Nb(3), one Nb(4), one Nb(5), and one Nb(6) atom to form distorted face-sharing TeNb6 pentagonal pyramids. In the fourth Te site, Te(4) is bonded in a 4-coordinate geometry to one Nb(2), one Nb(4), and two equivalent Nb(7) atoms. In the fifth Te site, Te(5) is bonded in a 5-coordinate geometry to one Nb(1), one Nb(3), two equivalent Nb(7), and one Tl(1) atom. In the sixth Te site, Te(6) is bonded in a 4-coordinate geometry to one Nb(4), one Nb(6), and two equivalent Nb(8) atoms. In the seventh Te site, Te(7) is bonded in a 5-coordinate geometry to one Nb(3), one Nb(5), two equivalent Nb(8), and one Tl(1) atom. In the eighth Te site, Te(8) is bonded in a 5-coordinate geometry to one Nb(2), one Nb(6), two equivalent Nb(9), and one Tl(1) atom. In the ninth Te site, Te(9) is bonded in a 4-coordinate geometry to one Nb(1), one Nb(5), and two equivalent Nb(9) atoms. In the tenth Te site, Te(10) is bonded in a 4-coordinate geometry to one Nb(1), one Nb(2), one Nb(7), and one Nb(8) atom. In the eleventh Te site, Te(11) is bonded in a 4-coordinate geometry to one Nb(3), one Nb(4), one Nb(8), and one Nb(9) atom. In the twelfth Te site, Te(12) is bonded in a 4-coordinate geometry to one Nb(5), one Nb(6), one Nb(7), and one Nb(9) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Nb12TlTe16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.447
_cell_length_b   11.447
_cell_length_c   10.846
_cell_angle_alpha   61.747
_cell_angle_beta   61.747
_cell_angle_gamma   37.520
_symmetry_Int_Tables_number   1
_cell_volume   749.663
_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  0.118  0.118  0.899  1.0
  Nb  Nb1  1  0.619  0.619  0.900  1.0
  Nb  Nb2  1  0.325  0.325  0.614  1.0
  Nb  Nb3  1  0.824  0.824  0.613  1.0
  Nb  Nb4  1  0.181  0.181  0.488  1.0
  Nb  Nb5  1  0.683  0.683  0.486  1.0
  Nb  Nb6  1  0.874  0.386  0.100  1.0
  Nb  Nb7  1  0.386  0.874  0.100  1.0
  Nb  Nb8  1  0.675  0.176  0.390  1.0
  Nb  Nb9  1  0.176  0.675  0.390  1.0
  Nb  Nb10  1  0.826  0.314  0.510  1.0
  Nb  Nb11  1  0.314  0.826  0.510  1.0
  Tl  Tl12  1  0.376  0.376  0.999  1.0
  Te  Te13  1  0.541  0.541  0.335  1.0
  Te  Te14  1  0.042  0.042  0.331  1.0
  Te  Te15  1  0.458  0.959  0.667  1.0
  Te  Te16  1  0.959  0.458  0.667  1.0
  Te  Te17  1  0.738  0.738  0.935  1.0
  Te  Te18  1  0.235  0.235  0.937  1.0
  Te  Te19  1  0.843  0.843  0.339  1.0
  Te  Te20  1  0.343  0.343  0.341  1.0
  Te  Te21  1  0.546  0.546  0.720  1.0
  Te  Te22  1  0.044  0.044  0.727  1.0
  Te  Te23  1  0.261  0.760  0.063  1.0
  Te  Te24  1  0.760  0.261  0.063  1.0
  Te  Te25  1  0.155  0.658  0.665  1.0
  Te  Te26  1  0.658  0.155  0.665  1.0
  Te  Te27  1  0.458  0.957  0.272  1.0
  Te  Te28  1  0.957  0.458  0.272  1.0
[/CIF]
.
The compound described by Nb12TlTe16 crystallizes in the monoclinic Cm space group. There are nine inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one Te(5), one Te(9), two equivalent Te(10), and two equivalent Te(3) atoms. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one Te(4), one Te(8), two equivalent Te(10), and two equivalent Te(3) atoms. In the third Nb site, Nb(3) is bonded in a 6-coordinate geometry to one Te(5), one Te(7), two equivalent Te(11), and two equivalent Te(3) atoms. In the fourth Nb site, Nb(4) is bonded in a 6-coordinate geometry to one Te(4), one Te(6), two equivalent Te(11), and two equivalent Te(3) atoms. In the fifth Nb site, Nb(5) is bonded in a 6-coordinate geometry to one Te(7), one Te(9), two equivalent Te(12), and two equivalent Te(3) atoms. In the sixth Nb site, Nb(6) is bonded in a 6-coordinate geometry to one Te(6), one Te(8), two equivalent Te(12), and two equivalent Te(3) atoms. In the seventh Nb site, Nb(7) is bonded in a 6-coordinate geometry to one Te(1), one Te(10), one Te(12), one Te(2), one Te(4), and one Te(5) atom. In the eighth Nb site, Nb(8) is bonded in a 6-coordinate geometry to one Te(1), one Te(10), one Te(11), one Te(2), one Te(6), and one Te(7) atom. In the ninth Nb site, Nb(9) is bonded in a 6-coordinate geometry to one Te(1), one Te(11), one Te(12), one Te(2), one Te(8), and one Te(9) atom. Tl(1) is bonded in a trigonal planar geometry to one Te(5), one Te(7), and one Te(8) atom. There are twelve inequivalent Te sites. In the first Te site, Te(1) is bonded to two equivalent Nb(7), two equivalent Nb(8), and two equivalent Nb(9) atoms to form distorted face-sharing TeNb6 pentagonal pyramids. In the second Te site, Te(2) is bonded to two equivalent Nb(7), two equivalent Nb(8), and two equivalent Nb(9) atoms to form distorted face-sharing TeNb6 pentagonal pyramids. In the third Te site, Te(3) is bonded to one Nb(1), one Nb(2), one Nb(3), one Nb(4), one Nb(5), and one Nb(6) atom to form distorted face-sharing TeNb6 pentagonal pyramids. In the fourth Te site, Te(4) is bonded in a 4-coordinate geometry to one Nb(2), one Nb(4), and two equivalent Nb(7) atoms. In the fifth Te site, Te(5) is bonded in a 5-coordinate geometry to one Nb(1), one Nb(3), two equivalent Nb(7), and one Tl(1) atom. In the sixth Te site, Te(6) is bonded in a 4-coordinate geometry to one Nb(4), one Nb(6), and two equivalent Nb(8) atoms. In the seventh Te site, Te(7) is bonded in a 5-coordinate geometry to one Nb(3), one Nb(5), two equivalent Nb(8), and one Tl(1) atom. In the eighth Te site, Te(8) is bonded in a 5-coordinate geometry to one Nb(2), one Nb(6), two equivalent Nb(9), and one Tl(1) atom. In the ninth Te site, Te(9) is bonded in a 4-coordinate geometry to one Nb(1), one Nb(5), and two equivalent Nb(9) atoms. In the tenth Te site, Te(10) is bonded in a 4-coordinate geometry to one Nb(1), one Nb(2), one Nb(7), and one Nb(8) atom. In the eleventh Te site, Te(11) is bonded in a 4-coordinate geometry to one Nb(3), one Nb(4), one Nb(8), and one Nb(9) atom. In the twelfth Te site, Te(12) is bonded in a 4-coordinate geometry to one Nb(5), one Nb(6), one Nb(7), and one Nb(9) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Nb12TlTe16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.447
_cell_length_b   11.447
_cell_length_c   10.846
_cell_angle_alpha   61.747
_cell_angle_beta   61.747
_cell_angle_gamma   37.520
_symmetry_Int_Tables_number   1
_cell_volume   749.663
_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  0.118  0.118  0.899  1.0
  Nb  Nb1  1  0.619  0.619  0.900  1.0
  Nb  Nb2  1  0.325  0.325  0.614  1.0
  Nb  Nb3  1  0.824  0.824  0.613  1.0
  Nb  Nb4  1  0.181  0.181  0.488  1.0
  Nb  Nb5  1  0.683  0.683  0.486  1.0
  Nb  Nb6  1  0.874  0.386  0.100  1.0
  Nb  Nb7  1  0.386  0.874  0.100  1.0
  Nb  Nb8  1  0.675  0.176  0.390  1.0
  Nb  Nb9  1  0.176  0.675  0.390  1.0
  Nb  Nb10  1  0.826  0.314  0.510  1.0
  Nb  Nb11  1  0.314  0.826  0.510  1.0
  Tl  Tl12  1  0.376  0.376  0.999  1.0
  Te  Te13  1  0.541  0.541  0.335  1.0
  Te  Te14  1  0.042  0.042  0.331  1.0
  Te  Te15  1  0.458  0.959  0.667  1.0
  Te  Te16  1  0.959  0.458  0.667  1.0
  Te  Te17  1  0.738  0.738  0.935  1.0
  Te  Te18  1  0.235  0.235  0.937  1.0
  Te  Te19  1  0.843  0.843  0.339  1.0
  Te  Te20  1  0.343  0.343  0.341  1.0
  Te  Te21  1  0.546  0.546  0.720  1.0
  Te  Te22  1  0.044  0.044  0.727  1.0
  Te  Te23  1  0.261  0.760  0.063  1.0
  Te  Te24  1  0.760  0.261  0.063  1.0
  Te  Te25  1  0.155  0.658  0.665  1.0
  Te  Te26  1  0.658  0.155  0.665  1.0
  Te  Te27  1  0.458  0.957  0.272  1.0
  Te  Te28  1  0.957  0.458  0.272  1.0
[/CIF]
.