data_Ca2NbHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.48
_cell_length_b   5.02
_cell_length_c   6.45
_cell_angle_alpha   90.0
_cell_angle_beta   104.83
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca2NbHg
_chemical_formula_sum   'Ca2 Nb1 Hg1'
_cell_volume   108.78
_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
  Ca  Ca0  1  0.53  0.51  0.91  1.0
  Ca  Ca1  1  0.01  0.0  0.87  1.0
  Nb  Nb3  1  0.25  0.0  0.63  1.0
  Hg  Hg2  1  0.3  0.51  0.17  1.0

data_Ca2NbHg
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.48
_cell_length_b   5.02
_cell_length_c   6.45
_cell_angle_alpha   90.0
_cell_angle_beta   104.83
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca2NbHg
_chemical_formula_sum   'Ca2 Nb1 Hg1'
_cell_volume   108.78
_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
  Ca  Ca0  1  0.01  0.0  0.87  1.0
  Ca  Ca1  1  0.53  0.51  0.91  1.0
  Nb  Nb2  1  0.25  0.0  0.63  1.0
  Hg  Hg3  1  0.3  0.51  0.17  1.0

Ca Ca Nb Hg
Ca Ca Nb Hg 0 3 o o + 1 2 o o o 