The structure described by K2Si4O9 crystallizes in the triclinic P-1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(4), one O(6), one O(9), and two equivalent O(8) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(3), one O(5), one O(7), one O(8), and three equivalent O(9) atoms. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(4), one O(7), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(3), one O(5), one O(6), and one O(9) atom to form corner-sharing SiO4 tetrahedra. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one K(1), one Si(2), and one Si(3) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one K(1), one Si(1), and one Si(3) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one K(2), one Si(2), and one Si(4) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one K(1), one Si(1), and one Si(3) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one K(2), one Si(2), and one Si(4) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one K(1), one Si(2), and one Si(4) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one K(2), one Si(1), and one Si(3) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one Si(1) atom. In the ninth O site, O(9) is bonded in a distorted single-bond geometry to one K(1), three equivalent K(2), and one Si(4) atom. is represented by the CIF file [CIF]
data_K2Si4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.939
_cell_length_b   8.346
_cell_length_c   12.124
_cell_angle_alpha   71.141
_cell_angle_beta   89.681
_cell_angle_gamma   89.076
_symmetry_Int_Tables_number   1
_cell_volume   472.889
_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
  K  K0  1  0.743  0.587  0.348  1.0
  K  K1  1  0.257  0.413  0.652  1.0
  K  K2  1  0.237  0.936  0.139  1.0
  K  K3  1  0.763  0.064  0.861  1.0
  Si  Si4  1  0.716  0.184  0.554  1.0
  Si  Si5  1  0.205  0.442  0.146  1.0
  Si  Si6  1  0.211  0.200  0.399  1.0
  Si  Si7  1  0.284  0.816  0.446  1.0
  Si  Si8  1  0.789  0.800  0.601  1.0
  Si  Si9  1  0.795  0.558  0.854  1.0
  Si  Si10  1  0.706  0.671  0.063  1.0
  Si  Si11  1  0.294  0.329  0.937  1.0
  O  O12  1  0.714  0.651  0.719  1.0
  O  O13  1  0.902  0.230  0.434  1.0
  O  O14  1  0.394  0.605  0.093  1.0
  O  O15  1  0.286  0.349  0.281  1.0
  O  O16  1  0.404  0.212  0.503  1.0
  O  O17  1  0.098  0.770  0.566  1.0
  O  O18  1  0.596  0.788  0.497  1.0
  O  O19  1  0.760  0.692  0.925  1.0
  O  O20  1  0.606  0.395  0.907  1.0
  O  O21  1  0.240  0.308  0.075  1.0
  O  O22  1  0.893  0.508  0.141  1.0
  O  O23  1  0.243  0.020  0.376  1.0
  O  O24  1  0.107  0.492  0.859  1.0
  O  O25  1  0.768  0.295  0.633  1.0
  O  O26  1  0.757  0.980  0.624  1.0
  O  O27  1  0.232  0.705  0.367  1.0
  O  O28  1  0.249  0.163  0.907  1.0
  O  O29  1  0.751  0.837  0.093  1.0
[/CIF]
.
The structure described by K2Si4O9 crystallizes in the triclinic P-1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(4), one O(6), one O(9), and two equivalent O(8) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(3), one O(5), one O(7), one O(8), and three equivalent O(9) atoms. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(4), one O(7), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(3), one O(5), one O(6), and one O(9) atom to form corner-sharing SiO4 tetrahedra. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one K(1), one Si(2), and one Si(3) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one K(1), one Si(1), and one Si(3) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one K(2), one Si(2), and one Si(4) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one K(1), one Si(1), and one Si(3) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one K(2), one Si(2), and one Si(4) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one K(1), one Si(2), and one Si(4) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one K(2), one Si(1), and one Si(3) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one Si(1) atom. In the ninth O site, O(9) is bonded in a distorted single-bond geometry to one K(1), three equivalent K(2), and one Si(4) atom. is represented by the CIF file [CIF]
data_K2Si4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.939
_cell_length_b   8.346
_cell_length_c   12.124
_cell_angle_alpha   71.141
_cell_angle_beta   89.681
_cell_angle_gamma   89.076
_symmetry_Int_Tables_number   1
_cell_volume   472.889
_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
  K  K0  1  0.743  0.587  0.348  1.0
  K  K1  1  0.257  0.413  0.652  1.0
  K  K2  1  0.237  0.936  0.139  1.0
  K  K3  1  0.763  0.064  0.861  1.0
  Si  Si4  1  0.716  0.184  0.554  1.0
  Si  Si5  1  0.205  0.442  0.146  1.0
  Si  Si6  1  0.211  0.200  0.399  1.0
  Si  Si7  1  0.284  0.816  0.446  1.0
  Si  Si8  1  0.789  0.800  0.601  1.0
  Si  Si9  1  0.795  0.558  0.854  1.0
  Si  Si10  1  0.706  0.671  0.063  1.0
  Si  Si11  1  0.294  0.329  0.937  1.0
  O  O12  1  0.714  0.651  0.719  1.0
  O  O13  1  0.902  0.230  0.434  1.0
  O  O14  1  0.394  0.605  0.093  1.0
  O  O15  1  0.286  0.349  0.281  1.0
  O  O16  1  0.404  0.212  0.503  1.0
  O  O17  1  0.098  0.770  0.566  1.0
  O  O18  1  0.596  0.788  0.497  1.0
  O  O19  1  0.760  0.692  0.925  1.0
  O  O20  1  0.606  0.395  0.907  1.0
  O  O21  1  0.240  0.308  0.075  1.0
  O  O22  1  0.893  0.508  0.141  1.0
  O  O23  1  0.243  0.020  0.376  1.0
  O  O24  1  0.107  0.492  0.859  1.0
  O  O25  1  0.768  0.295  0.633  1.0
  O  O26  1  0.757  0.980  0.624  1.0
  O  O27  1  0.232  0.705  0.367  1.0
  O  O28  1  0.249  0.163  0.907  1.0
  O  O29  1  0.751  0.837  0.093  1.0
[/CIF]
.