data_Tb2Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.01
_cell_length_b   7.01
_cell_length_c   7.01
_cell_angle_alpha   149.75
_cell_angle_beta   149.75
_cell_angle_gamma   43.31
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Tb2Mg
_chemical_formula_sum   'Tb2 Mg1'
_cell_volume   87.33
_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
  Tb  Tb1  1  0.0  0.0  0.6  1.0
  Tb  Tb2  1  0.0  0.0  0.43  1.0
  Mg  Mg0  1  0.0  0.0  0.0  1.0

data_Tb2Mg
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.18
_cell_length_b   5.18
_cell_length_c   7.01
_cell_angle_alpha   90.0
_cell_angle_beta   111.66
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Tb2Mg
_chemical_formula_sum   'Tb4 Mg2'
_cell_volume   174.65
_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
  Tb  Tb0  2  0.0  0.0  0.4  1.0
  Tb  Tb1  2  0.0  0.0  0.57  1.0
  Mg  Mg2  2  0.0  0.0  0.0  1.0

Tb Tb Mg
Tb Tb Mg 0 1 o o o 0 2 o o + 1 2 o o o 