data_K2Nb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.26
_cell_length_b   7.26
_cell_length_c   11.32
_cell_angle_alpha   101.92
_cell_angle_beta   101.92
_cell_angle_gamma   26.38
_symmetry_Int_Tables_number   1
_chemical_formula_structural   K2Nb
_chemical_formula_sum   'K4 Nb2'
_cell_volume   258.97
_cell_formula_units_Z   2
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  0.86  0.0  0.89  1.0
  K  K1  1  0.39  0.0  0.66  1.0
  K  K2  1  0.79  0.0  0.08  1.0
  K  K3  1  0.86  0.0  0.03  1.0
  Nb  Nb4  1  0.23  0.0  0.1  1.0
  Nb  Nb5  1  0.29  0.0  0.65  1.0

data_K2Nb
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.31
_cell_length_b   7.26
_cell_length_c   11.32
_cell_angle_alpha   101.92
_cell_angle_beta   90.0
_cell_angle_gamma   103.19
_symmetry_Int_Tables_number   1
_chemical_formula_structural   K2Nb
_chemical_formula_sum   'K4 Nb2'
_cell_volume   258.97
_cell_formula_units_Z   2
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  0.14  0.97  1.0
  K  K1  1  0.0  0.14  0.11  1.0
  K  K2  1  0.0  0.21  0.92  1.0
  K  K3  1  0.0  0.61  0.34  1.0
  Nb  Nb4  1  0.0  0.71  0.35  1.0
  Nb  Nb5  1  0.0  0.77  0.9  1.0

K K K K Nb Nb
K K K K Nb Nb 0 3 o o + 0 4 + o + 1 5 o o o 2 3 o o o 2 4 + o o 3 4 + o o 4 4 + - o 