data_K2NaCu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.86
_cell_length_b   5.86
_cell_length_c   4.71
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   K2NaCu
_chemical_formula_sum   'K2 Na1 Cu1'
_cell_volume   162.09
_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  0.93  0.0  0.36  1.0
  K  K2  1  0.0  0.93  0.36  1.0
  Na  Na3  1  0.0  0.0  0.0  1.0
  Cu  Cu0  1  0.93  0.93  0.0  1.0

data_K2NaCu
_symmetry_space_group_name_H-M   Cm
_cell_length_a   8.29
_cell_length_b   8.29
_cell_length_c   4.71
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   K2NaCu
_chemical_formula_sum   'K4 Na2 Cu2'
_cell_volume   324.18
_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
  K  K0  4  0.47  0.47  0.36  1.0
  Na  Na1  2  0.0  0.0  0.0  1.0
  Cu  Cu2  2  0.43  0.5  -0.0  1.0

K K Na Cu
K K Na Cu 0 1 + - o 2 3 - - o 
(K)2NaCu crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two potassio-kalium molecules and two NaCu clusters. In each NaCu cluster, Na(1) is bonded in a single-bond geometry to one Cu(1) atom. The Na(1)-Cu(1) bond length is 0.56 Å. Cu(1) is bonded in a single-bond geometry to one Na(1) atom.