The crystal structure described by Si is Clathrate-like structured and crystallizes in the orthorhombic Cmcm space group. There are nine inequivalent Si sites. In the first Si site, Si(1) is bonded to one Si(2), one Si(3), one Si(5), and one Si(8) atom to form corner-sharing SiSi4 tetrahedra. In the second Si site, Si(6) is bonded to one Si(5), one Si(6), and two equivalent Si(4) atoms to form a mixture of edge and corner-sharing SiSi4 tetrahedra. In the third Si site, Si(7) is bonded to one Si(8), one Si(9), and two equivalent Si(3) atoms to form corner-sharing SiSi4 tetrahedra. In the fourth Si site, Si(2) is bonded to one Si(1), one Si(2), one Si(3), and one Si(4) atom to form corner-sharing SiSi4 tetrahedra. In the fifth Si site, Si(8) is bonded to one Si(7), one Si(8), and two equivalent Si(1) atoms to form corner-sharing SiSi4 tetrahedra. In the sixth Si site, Si(9) is bonded to two equivalent Si(5) and two equivalent Si(7) atoms to form corner-sharing SiSi4 tetrahedra. In the seventh Si site, Si(3) is bonded to one Si(1), one Si(2), one Si(3), and one Si(7) atom to form corner-sharing SiSi4 tetrahedra. In the eighth Si site, Si(4) is bonded to two equivalent Si(2) and two equivalent Si(6) atoms to form a mixture of edge and corner-sharing SiSi4 tetrahedra. In the ninth Si site, Si(5) is bonded to one Si(6), one Si(9), and two equivalent Si(1) atoms to form corner-sharing SiSi4 tetrahedra. is represented by the CIF card [CIF]
data_Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.981
_cell_length_b   10.538
_cell_length_c   10.538
_cell_angle_alpha   105.141
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1069.797
_cell_formula_units_Z   46
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  0.059  0.332  0.094  1.0
  Si  Si1  1  0.941  0.906  0.668  1.0
  Si  Si2  1  0.441  0.332  0.094  1.0
  Si  Si3  1  0.559  0.906  0.668  1.0
  Si  Si4  1  0.941  0.668  0.906  1.0
  Si  Si5  1  0.059  0.094  0.332  1.0
  Si  Si6  1  0.559  0.668  0.906  1.0
  Si  Si7  1  0.441  0.094  0.332  1.0
  Si  Si8  1  0.127  0.552  0.199  1.0
  Si  Si9  1  0.873  0.801  0.448  1.0
  Si  Si10  1  0.373  0.552  0.199  1.0
  Si  Si11  1  0.627  0.801  0.448  1.0
  Si  Si12  1  0.873  0.448  0.801  1.0
  Si  Si13  1  0.127  0.199  0.552  1.0
  Si  Si14  1  0.627  0.448  0.801  1.0
  Si  Si15  1  0.373  0.199  0.552  1.0
  Si  Si16  1  0.059  0.726  0.111  1.0
  Si  Si17  1  0.941  0.889  0.274  1.0
  Si  Si18  1  0.441  0.726  0.111  1.0
  Si  Si19  1  0.559  0.889  0.274  1.0
  Si  Si20  1  0.941  0.274  0.889  1.0
  Si  Si21  1  0.059  0.111  0.726  1.0
  Si  Si22  1  0.559  0.274  0.889  1.0
  Si  Si23  1  0.441  0.111  0.726  1.0
  Si  Si24  1  0.000  0.601  0.399  1.0
  Si  Si25  1  0.500  0.601  0.399  1.0
  Si  Si26  1  0.000  0.399  0.601  1.0
  Si  Si27  1  0.500  0.399  0.601  1.0
  Si  Si28  1  0.939  0.248  0.248  1.0
  Si  Si29  1  0.061  0.752  0.752  1.0
  Si  Si30  1  0.561  0.248  0.248  1.0
  Si  Si31  1  0.439  0.752  0.752  1.0
  Si  Si32  1  0.869  0.421  0.421  1.0
  Si  Si33  1  0.131  0.579  0.579  1.0
  Si  Si34  1  0.631  0.421  0.421  1.0
  Si  Si35  1  0.369  0.579  0.579  1.0
  Si  Si36  1  0.750  0.929  0.160  1.0
  Si  Si37  1  0.250  0.840  0.071  1.0
  Si  Si38  1  0.250  0.071  0.840  1.0
  Si  Si39  1  0.750  0.160  0.929  1.0
  Si  Si40  1  0.750  0.943  0.801  1.0
  Si  Si41  1  0.250  0.199  0.057  1.0
  Si  Si42  1  0.250  0.057  0.199  1.0
  Si  Si43  1  0.750  0.801  0.943  1.0
  Si  Si44  1  0.750  0.144  0.144  1.0
  Si  Si45  1  0.250  0.856  0.856  1.0
[/CIF]
.
The crystal structure described by Si is Clathrate-like structured and crystallizes in the orthorhombic Cmcm space group. There are nine inequivalent Si sites. In the first Si site, Si(1) is bonded to one Si(2), one Si(3), one Si(5), and one Si(8) atom to form corner-sharing SiSi4 tetrahedra. In the second Si site, Si(6) is bonded to one Si(5), one Si(6), and two equivalent Si(4) atoms to form a mixture of edge and corner-sharing SiSi4 tetrahedra. In the third Si site, Si(7) is bonded to one Si(8), one Si(9), and two equivalent Si(3) atoms to form corner-sharing SiSi4 tetrahedra. In the fourth Si site, Si(2) is bonded to one Si(1), one Si(2), one Si(3), and one Si(4) atom to form corner-sharing SiSi4 tetrahedra. In the fifth Si site, Si(8) is bonded to one Si(7), one Si(8), and two equivalent Si(1) atoms to form corner-sharing SiSi4 tetrahedra. In the sixth Si site, Si(9) is bonded to two equivalent Si(5) and two equivalent Si(7) atoms to form corner-sharing SiSi4 tetrahedra. In the seventh Si site, Si(3) is bonded to one Si(1), one Si(2), one Si(3), and one Si(7) atom to form corner-sharing SiSi4 tetrahedra. In the eighth Si site, Si(4) is bonded to two equivalent Si(2) and two equivalent Si(6) atoms to form a mixture of edge and corner-sharing SiSi4 tetrahedra. In the ninth Si site, Si(5) is bonded to one Si(6), one Si(9), and two equivalent Si(1) atoms to form corner-sharing SiSi4 tetrahedra. is represented by the CIF card [CIF]
data_Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.981
_cell_length_b   10.538
_cell_length_c   10.538
_cell_angle_alpha   105.141
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1069.797
_cell_formula_units_Z   46
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  0.059  0.332  0.094  1.0
  Si  Si1  1  0.941  0.906  0.668  1.0
  Si  Si2  1  0.441  0.332  0.094  1.0
  Si  Si3  1  0.559  0.906  0.668  1.0
  Si  Si4  1  0.941  0.668  0.906  1.0
  Si  Si5  1  0.059  0.094  0.332  1.0
  Si  Si6  1  0.559  0.668  0.906  1.0
  Si  Si7  1  0.441  0.094  0.332  1.0
  Si  Si8  1  0.127  0.552  0.199  1.0
  Si  Si9  1  0.873  0.801  0.448  1.0
  Si  Si10  1  0.373  0.552  0.199  1.0
  Si  Si11  1  0.627  0.801  0.448  1.0
  Si  Si12  1  0.873  0.448  0.801  1.0
  Si  Si13  1  0.127  0.199  0.552  1.0
  Si  Si14  1  0.627  0.448  0.801  1.0
  Si  Si15  1  0.373  0.199  0.552  1.0
  Si  Si16  1  0.059  0.726  0.111  1.0
  Si  Si17  1  0.941  0.889  0.274  1.0
  Si  Si18  1  0.441  0.726  0.111  1.0
  Si  Si19  1  0.559  0.889  0.274  1.0
  Si  Si20  1  0.941  0.274  0.889  1.0
  Si  Si21  1  0.059  0.111  0.726  1.0
  Si  Si22  1  0.559  0.274  0.889  1.0
  Si  Si23  1  0.441  0.111  0.726  1.0
  Si  Si24  1  0.000  0.601  0.399  1.0
  Si  Si25  1  0.500  0.601  0.399  1.0
  Si  Si26  1  0.000  0.399  0.601  1.0
  Si  Si27  1  0.500  0.399  0.601  1.0
  Si  Si28  1  0.939  0.248  0.248  1.0
  Si  Si29  1  0.061  0.752  0.752  1.0
  Si  Si30  1  0.561  0.248  0.248  1.0
  Si  Si31  1  0.439  0.752  0.752  1.0
  Si  Si32  1  0.869  0.421  0.421  1.0
  Si  Si33  1  0.131  0.579  0.579  1.0
  Si  Si34  1  0.631  0.421  0.421  1.0
  Si  Si35  1  0.369  0.579  0.579  1.0
  Si  Si36  1  0.750  0.929  0.160  1.0
  Si  Si37  1  0.250  0.840  0.071  1.0
  Si  Si38  1  0.250  0.071  0.840  1.0
  Si  Si39  1  0.750  0.160  0.929  1.0
  Si  Si40  1  0.750  0.943  0.801  1.0
  Si  Si41  1  0.250  0.199  0.057  1.0
  Si  Si42  1  0.250  0.057  0.199  1.0
  Si  Si43  1  0.750  0.801  0.943  1.0
  Si  Si44  1  0.750  0.144  0.144  1.0
  Si  Si45  1  0.250  0.856  0.856  1.0
[/CIF]
.