data_YSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.02
_cell_length_b   6.02
_cell_length_c   6.02
_cell_angle_alpha   143.59
_cell_angle_beta   137.05
_cell_angle_gamma   57.54
_symmetry_Int_Tables_number   1
_chemical_formula_structural   YSi
_chemical_formula_sum   'Y2 Si2'
_cell_volume   87.3
_cell_formula_units_Z   2
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
  Y  Y2  1  0.0  0.1  0.01  1.0
  Y  Y3  1  0.88  0.1  0.26  1.0
  Si  Si0  1  0.88  0.9  0.52  1.0
  Si  Si1  1  0.0  0.3  0.75  1.0

data_YSi
_symmetry_space_group_name_H-M   P-1
_cell_length_a   3.76
_cell_length_b   4.4
_cell_length_c   6.02
_cell_angle_alpha   111.48
_cell_angle_beta   108.21
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   2
_chemical_formula_structural   YSi
_chemical_formula_sum   'Y2 Si2'
_cell_volume   87.3
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-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
  Y  Y0  2  0.5  0.88  0.82  1.0
  Si  Si1  2  0.3  0.41  0.35  1.0

Y Y Si Si
Y Y Si Si 0 2 - - - 1 3 + o o 2 3 + + o 