data_Ca2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.09
_cell_length_b   5.09
_cell_length_c   6.99
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca2Si
_chemical_formula_sum   'Ca4 Si2'
_cell_volume   156.63
_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
  Ca  Ca0  1  0.0  0.0  0.0  1.0
  Ca  Ca1  1  0.0  0.0  0.49  1.0
  Ca  Ca2  1  0.54  0.47  0.75  1.0
  Ca  Ca3  1  0.0  0.94  0.24  1.0
  Si  Si4  1  0.0  0.94  0.75  1.0
  Si  Si5  1  0.54  0.47  0.24  1.0

data_Ca2Si
_symmetry_space_group_name_H-M   Pm
_cell_length_a   5.09
_cell_length_b   6.99
_cell_length_c   5.09
_cell_angle_alpha   90.0
_cell_angle_beta   120.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   6
_chemical_formula_structural   Ca2Si
_chemical_formula_sum   'Ca4 Si2'
_cell_volume   156.63
_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
  Ca  Ca0  2  0.0  0.25  0.0  1.0
  Ca  Ca1  1  0.0  0.5  0.94  1.0
  Ca  Ca2  1  0.54  0.0  0.47  1.0
  Si  Si3  1  0.0  0.0  0.94  1.0
  Si  Si4  1  0.54  0.5  0.47  1.0

Ca Ca Ca Ca Si Si
Ca Ca Ca Ca Si Si 0 4 o - - 0 3 o - o 0 5 - - o 1 3 o - o 1 4 o - o 1 5 - - o 2 4 o - o 2 4 + o o 3 5 o + o 3 5 - o o 