data_Si3As5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.18
_cell_length_b   7.18
_cell_length_c   6.8
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si3As5
_chemical_formula_sum   'Si6 As10'
_cell_volume   303.8
_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
  Si  Si10  1  0.47  0.65  0.1  1.0
  Si  Si11  1  0.94  0.57  0.7  1.0
  Si  Si12  1  0.06  0.57  0.1  1.0
  Si  Si13  1  0.06  0.0  0.1  1.0
  Si  Si14  1  0.12  0.0  0.7  1.0
  Si  Si15  1  0.53  0.65  0.7  1.0
  As  As0  1  0.59  0.07  0.4  1.0
  As  As1  1  0.0  0.15  0.0  1.0
  As  As2  1  0.0  0.15  0.4  1.0
  As  As3  1  0.59  0.07  0.0  1.0
  As  As4  1  0.21  0.83  0.1  1.0
  As  As5  1  0.2  0.39  0.7  1.0
  As  As6  1  0.8  0.39  0.1  1.0
  As  As7  1  0.57  0.0  0.1  1.0
  As  As8  1  0.61  0.0  0.7  1.0
  As  As9  1  0.79  0.83  0.7  1.0

data_Si3As5
_symmetry_space_group_name_H-M   P1
_cell_length_a   6.8
_cell_length_b   7.18
_cell_length_c   7.18
_cell_angle_alpha   120.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si3As5
_chemical_formula_sum   'Si6 As10'
_cell_volume   303.8
_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
  Si  Si0  1  0.1  0.06  0.0  1.0
  Si  Si1  1  0.1  0.06  0.57  1.0
  Si  Si2  1  0.1  0.47  0.65  1.0
  Si  Si3  1  0.7  0.12  0.0  1.0
  Si  Si4  1  0.7  0.53  0.65  1.0
  Si  Si5  1  0.7  0.94  0.57  1.0
  As  As6  1  0.0  0.0  0.15  1.0
  As  As7  1  0.0  0.59  0.07  1.0
  As  As8  1  0.1  0.21  0.83  1.0
  As  As9  1  0.1  0.57  0.0  1.0
  As  As10  1  0.1  0.8  0.39  1.0
  As  As11  1  0.4  0.0  0.15  1.0
  As  As12  1  0.4  0.59  0.07  1.0
  As  As13  1  0.7  0.2  0.39  1.0
  As  As14  1  0.7  0.61  0.0  1.0
  As  As15  1  0.7  0.79  0.83  1.0

Si Si Si Si Si Si As As As As As As As As As As
Si3As5 crystallizes in the triclinic P1 space group. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded in a distorted single-bond geometry to one As(8) atom. The Si(1)-As(8) bond length is 2.25 Å. In the second Si site, Si(2) is bonded in a 2-coordinate geometry to one As(10) and one As(6) atom. The Si(2)-As(10) bond length is 2.57 Å. The Si(2)-As(6) bond length is 2.73 Å. In the third Si site, Si(3) is bonded in a distorted bent 150 degrees geometry to one As(5) and one As(7) atom. The Si(3)-As(5) bond length is 1.60 Å. The Si(3)-As(7) bond length is 1.64 Å. In the fourth Si site, Si(4) is bonded in a 3-coordinate geometry to one As(2), one As(3), and one As(5) atom. The Si(4)-As(2) bond length is 1.48 Å. The Si(4)-As(3) bond length is 2.41 Å. The Si(4)-As(5) bond length is 2.05 Å. In the fifth Si site, Si(5) is bonded in a 1-coordinate geometry to one As(10), one As(3), and one As(6) atom. The Si(5)-As(10) bond length is 2.09 Å. The Si(5)-As(3) bond length is 2.63 Å. The Si(5)-As(6) bond length is 2.59 Å. In the sixth Si site, Si(6) is bonded in a 3-coordinate geometry to one As(10), one As(6), and one As(9) atom. The Si(6)-As(10) bond length is 1.64 Å. The Si(6)-As(6) bond length is 2.17 Å. The Si(6)-As(9) bond length is 2.30 Å. There are ten inequivalent As sites. In the first As site, As(1) is bonded in a 2-coordinate geometry to one As(3), one As(8), and one As(9) atom. The As(1)-As(3) bond length is 2.72 Å. The As(1)-As(8) bond length is 2.09 Å. The As(1)-As(9) bond length is 2.12 Å. In the second As site, As(2) is bonded in a single-bond geometry to one Si(4), one As(3), and one As(6) atom. The As(2)-As(3) bond length is 2.74 Å. The As(2)-As(6) bond length is 2.60 Å. In the third As site, As(3) is bonded in a 6-coordinate geometry to one Si(4), one Si(5), one As(1), one As(10), one As(2), and one As(6) atom. The As(3)-As(10) bond length is 2.87 Å. The As(3)-As(6) bond length is 2.60 Å. In the fourth As site, As(4) is bonded in a distorted single-bond geometry to one As(8) and one As(9) atom. The As(4)-As(8) bond length is 0.85 Å. The As(4)-As(9) bond length is 2.12 Å. In the fifth As site, As(5) is bonded in a distorted bent 120 degrees geometry to one Si(3) and one Si(4) atom. In the sixth As site, As(6) is bonded in a 5-coordinate geometry to one Si(2), one Si(5), one Si(6), one As(2), and one As(3) atom. In the seventh As site, As(7) is bonded in a single-bond geometry to one Si(3) atom. In the eighth As site, As(8) is bonded in a 1-coordinate geometry to one Si(1), one As(1), and one As(4) atom. In the ninth As site, As(9) is bonded in a 4-coordinate geometry to one Si(6), one As(1), one As(10), and one As(4) atom. The As(9)-As(10) bond length is 2.20 Å. In the tenth As site, As(10) is bonded in a 2-coordinate geometry to one Si(2), one Si(5), one Si(6), one As(3), and one As(9) atom.