data_MgNbTl2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.14
_cell_length_b   5.14
_cell_length_c   5.14
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgNbTl2
_chemical_formula_sum   'Mg1 Nb1 Tl2'
_cell_volume   96.24
_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
  Mg  Mg0  1  0.0  0.0  0.0  1.0
  Nb  Nb1  1  0.82  0.82  0.82  1.0
  Tl  Tl2  1  0.64  0.64  0.64  1.0
  Tl  Tl3  1  0.46  0.46  0.46  1.0

data_MgNbTl2
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.14
_cell_length_b   5.14
_cell_length_c   12.6
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   MgNbTl2
_chemical_formula_sum   'Mg3 Nb3 Tl6'
_cell_volume   288.72
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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
  Mg  Mg0  3  0.0  0.0  0.0  1.0
  Nb  Nb1  3  0.0  0.0  0.18  1.0
  Tl  Tl2  3  0.0  0.0  0.36  1.0
  Tl  Tl3  3  0.0  0.0  0.54  1.0

Mg Nb Tl Tl
Mg Nb Tl Tl 0 1 - - - 1 2 o o o 2 3 o o o 
MgNbTl2 crystallizes in the trigonal R3m space group. Mg(1) is bonded in a 1-coordinate geometry to one Nb(1), three equivalent Tl(1), and three equivalent Tl(2) atoms. The Mg(1)-Nb(1) bond length is 2.29 Å. All Mg(1)-Tl(1) bond lengths are 2.99 Å. All Mg(1)-Tl(2) bond lengths are 3.35 Å. Nb(1) is bonded in a distorted linear geometry to one Mg(1), one Tl(1), and three equivalent Tl(2) atoms. The Nb(1)-Tl(1) bond length is 2.29 Å. All Nb(1)-Tl(2) bond lengths are 2.99 Å. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded to three equivalent Mg(1), one Nb(1), and one Tl(2) atom to form corner-sharing TlMg3NbTl trigonal bipyramids. The Tl(1)-Tl(2) bond length is 2.29 Å. In the second Tl site, Tl(2) is bonded in a 7-coordinate geometry to three equivalent Mg(1), three equivalent Nb(1), and one Tl(1) atom.