data_Ba2Tl2Cu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.39
_cell_length_b   6.39
_cell_length_c   6.39
_cell_angle_alpha   115.43
_cell_angle_beta   115.43
_cell_angle_gamma   98.12
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ba2Tl2Cu
_chemical_formula_sum   'Ba2 Tl2 Cu1'
_cell_volume   195.14
_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
  Ba  Ba0  1  0.0  0.41  0.09  1.0
  Ba  Ba1  1  0.41  0.0  0.09  1.0
  Tl  Tl3  1  0.0  0.0  0.61  1.0
  Tl  Tl4  1  0.0  0.0  0.76  1.0
  Cu  Cu2  1  0.0  0.0  0.0  1.0

data_Ba2Tl2Cu
_symmetry_space_group_name_H-M   Cm
_cell_length_a   8.37
_cell_length_b   9.65
_cell_length_c   6.39
_cell_angle_alpha   90.0
_cell_angle_beta   130.94
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Ba2Tl2Cu
_chemical_formula_sum   'Ba4 Tl4 Cu2'
_cell_volume   390.28
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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
  Ba  Ba0  4  0.11  0.21  0.91  1.0
  Tl  Tl1  2  0.24  0.0  0.24  1.0
  Tl  Tl2  2  0.39  0.0  0.39  1.0
  Cu  Cu3  2  0.0  0.0  0.0  1.0

Ba Ba Tl Tl Cu
Ba2CuTl2 crystallizes in the monoclinic Cm space group. Ba(1) is bonded in a 4-coordinate geometry to two equivalent Cu(1), one Tl(1), and one Tl(2) atom. There is one shorter (2.44 Å) and one longer (4.04 Å) Ba(1)-Cu(1) bond length. The Ba(1)-Tl(1) bond length is 3.79 Å. The Ba(1)-Tl(2) bond length is 2.58 Å. Cu(1) is bonded in a 3-coordinate geometry to four equivalent Ba(1) and one Tl(2) atom. The Cu(1)-Tl(2) bond length is 1.52 Å. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a distorted single-bond geometry to two equivalent Ba(1) and one Tl(2) atom. The Tl(1)-Tl(2) bond length is 0.95 Å. In the second Tl site, Tl(2) is bonded in a distorted tetrahedral geometry to two equivalent Ba(1), one Cu(1), and one Tl(1) atom.