data_Mg2ZrNb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.96
_cell_length_b   2.96
_cell_length_c   9.66
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2ZrNb
_chemical_formula_sum   'Mg2 Zr1 Nb1'
_cell_volume   84.45
_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
  Mg  Mg0  1  0.48  0.48  0.04  1.0
  Mg  Mg1  1  0.0  0.0  0.5  1.0
  Zr  Zr3  1  0.0  0.0  0.11  1.0
  Nb  Nb2  1  0.48  0.48  0.83  1.0

data_Mg2ZrNb
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.18
_cell_length_b   4.18
_cell_length_c   9.66
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Mg2ZrNb
_chemical_formula_sum   'Mg4 Zr2 Nb2'
_cell_volume   168.9
_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
  Mg  Mg0  2  0.0  0.0  0.5  1.0
  Mg  Mg1  2  0.48  0.0  0.04  1.0
  Zr  Zr2  2  0.0  0.0  0.11  1.0
  Nb  Nb3  2  0.48  0.0  0.83  1.0

Mg Mg Zr Nb
Mg Mg Zr Nb 0 2 o o o 0 2 o + o 0 2 + o o 0 2 + + o 0 3 o o - 1 1 + o o 1 1 o + o 