data_K2TaCu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.87
_cell_length_b   7.87
_cell_length_c   4.71
_cell_angle_alpha   104.06
_cell_angle_beta   104.06
_cell_angle_gamma   21.36
_symmetry_Int_Tables_number   1
_chemical_formula_structural   K2TaCu
_chemical_formula_sum   'K2 Ta1 Cu1'
_cell_volume   102.89
_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
  K  K1  1  0.23  0.0  0.8  1.0
  K  K2  1  0.07  0.0  0.76  1.0
  Ta  Ta3  1  0.15  0.0  0.28  1.0
  Cu  Cu0  1  0.0  0.0  0.0  1.0

data_K2TaCu
_symmetry_space_group_name_H-M   P1
_cell_length_a   2.92
_cell_length_b   4.71
_cell_length_c   7.87
_cell_angle_alpha   104.06
_cell_angle_beta   100.68
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   K2TaCu
_chemical_formula_sum   'K2 Ta1 Cu1'
_cell_volume   102.89
_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
  K  K0  1  0.0  0.76  0.07  1.0
  K  K1  1  0.0  0.8  0.23  1.0
  Ta  Ta2  1  0.0  0.28  0.15  1.0
  Cu  Cu3  1  0.0  0.0  0.0  1.0

K K Ta Cu
K K Ta Cu 0 1 o o o 1 3 o o + 2 3 o o o 
K2TaCu crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one K2TaCu cluster. There are two inequivalent K sites. In the first K site, K(1) is bonded in a distorted single-bond geometry to one K(2) atom. The K(1)-K(2) bond length is 1.28 Å. In the second K site, K(2) is bonded in a 2-coordinate geometry to one K(1) and one Cu(1) atom. The K(2)-Cu(1) bond length is 1.37 Å. Ta(1) is bonded in a distorted single-bond geometry to one Cu(1) atom. The Ta(1)-Cu(1) bond length is 1.55 Å. Cu(1) is bonded in a water-like geometry to one K(2) and one Ta(1) atom.