data_K2MgCu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.76
_cell_length_b   3.9
_cell_length_c   9.16
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   K2MgCu
_chemical_formula_sum   'K2 Mg1 Cu1'
_cell_volume   134.32
_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  0.0  0.0  0.57  1.0
  K  K2  1  0.88  0.95  0.84  1.0
  Mg  Mg3  1  0.0  0.0  0.4  1.0
  Cu  Cu0  1  0.88  0.95  0.1  1.0

data_K2MgCu
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.76
_cell_length_b   3.9
_cell_length_c   9.16
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   K2MgCu
_chemical_formula_sum   'K2 Mg1 Cu1'
_cell_volume   134.32
_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  0.57  1.0
  K  K1  1  0.88  0.95  0.84  1.0
  Mg  Mg2  1  0.0  0.0  0.4  1.0
  Cu  Cu3  1  0.88  0.95  0.1  1.0

K K Mg Cu
K K Mg Cu 0 2 o o o 0 1 - - o 1 3 o o + 2 3 - - o 