data_KMg2Nb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.81
_cell_length_b   5.81
_cell_length_c   5.81
_cell_angle_alpha   132.15
_cell_angle_beta   132.15
_cell_angle_gamma   69.99
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KMg2Nb
_chemical_formula_sum   'K1 Mg2 Nb1'
_cell_volume   105.69
_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  0.0  0.76  1.0
  Mg  Mg1  1  0.0  0.36  0.38  1.0
  Mg  Mg2  1  0.0  0.0  0.0  1.0
  Nb  Nb3  1  0.36  0.0  0.38  1.0

data_KMg2Nb
_symmetry_space_group_name_H-M   P1
_cell_length_a   4.71
_cell_length_b   4.71
_cell_length_c   5.81
_cell_angle_alpha   113.93
_cell_angle_beta   113.93
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KMg2Nb
_chemical_formula_sum   'K1 Mg2 Nb1'
_cell_volume   105.69
_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  0.24  0.0  0.24  1.0
  Mg  Mg1  1  0.0  0.0  0.0  1.0
  Mg  Mg2  1  0.98  0.36  0.98  1.0
  Nb  Nb3  1  0.62  0.0  0.98  1.0

K Mg Mg Nb
K Mg Mg Nb 0 2 o o + 1 2 o o o 2 3 o o o 