data_Si2As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.38
_cell_length_b   7.38
_cell_length_c   3.46
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si2As
_chemical_formula_sum   'Si6 As3'
_cell_volume   163.03
_cell_formula_units_Z   3
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
  Si  Si3  1  0.02  0.0  0.73  1.0
  Si  Si4  1  0.99  0.75  0.73  1.0
  Si  Si5  1  0.68  0.64  0.73  1.0
  Si  Si6  1  0.95  0.0  0.0  1.0
  Si  Si7  1  0.02  0.42  0.0  1.0
  Si  Si8  1  0.71  0.97  0.0  1.0
  As  As0  1  0.0  0.26  0.73  1.0
  As  As1  1  0.69  0.13  0.73  1.0
  As  As2  1  0.0  0.0  0.0  1.0

data_Si2As
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.46
_cell_length_b   7.38
_cell_length_c   7.38
_cell_angle_alpha   120.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si2As
_chemical_formula_sum   'Si6 As3'
_cell_volume   163.03
_cell_formula_units_Z   3
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
  Si  Si0  1  0.0  0.02  0.42  1.0
  Si  Si1  1  0.0  0.71  0.97  1.0
  Si  Si2  1  0.0  0.95  0.0  1.0
  Si  Si3  1  0.73  0.02  0.0  1.0
  Si  Si4  1  0.73  0.68  0.64  1.0
  Si  Si5  1  0.73  0.99  0.75  1.0
  As  As6  1  0.0  0.0  0.0  1.0
  As  As7  1  0.73  0.0  0.26  1.0
  As  As8  1  0.73  0.69  0.13  1.0

Si Si Si Si Si Si As As As
Si Si Si Si Si Si As As As 0 8 o o + 0 3 - o + 0 1 - - o 1 2 o o o 1 8 + + + 1 3 o + + 2 5 o o + 3 8 + o o 3 5 o - o 4 6 o o - 5 7 o + - 