data_Li2MnNb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.46
_cell_length_b   3.46
_cell_length_c   4.85
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Li2MnNb
_chemical_formula_sum   'Li2 Mn1 Nb1'
_cell_volume   58.22
_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
  Li  Li0  1  0.73  0.0  0.43  1.0
  Li  Li1  1  0.0  0.73  0.43  1.0
  Mn  Mn2  1  0.0  0.0  0.0  1.0
  Nb  Nb3  1  0.73  0.73  0.0  1.0

data_Li2MnNb
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.9
_cell_length_b   4.9
_cell_length_c   4.85
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Li2MnNb
_chemical_formula_sum   'Li4 Mn2 Nb2'
_cell_volume   116.44
_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
  Li  Li0  4  0.37  0.37  0.43  1.0
  Mn  Mn1  2  0.0  0.0  0.0  1.0
  Nb  Nb2  2  0.23  0.5  -0.0  1.0

Li Li Mn Nb
Li Li Mn Nb 0 1 + - o 2 3 - - o 