The crystal structure described by K2Zn2Si8O19 crystallizes in the monoclinic C2 space group. K(1) is bonded in a 8-coordinate geometry to one O(10), one O(2), one O(3), one O(4), one O(6), one O(9), and two equivalent O(8) atoms. Zn(1) is bonded to one O(3), one O(8), and two equivalent O(10) atoms to form ZnO4 tetrahedra that share  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Zn(1)O4 tetrahedra, and corners with three equivalent Si(2)O4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(10), one O(2), one O(4), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with three equivalent Zn(1)O4 tetrahedra. In the third Si site, Si(3) is bonded to one O(1), one O(6), one O(7), and one O(9) atom to form corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(1), one O(3), one O(5), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Zn(1)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. There are ten inequivalent O sites. In the first O site, O(7) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the second O site, O(8) is bonded in a distorted bent 120 degrees geometry to two equivalent K(1), one Zn(1), and one Si(2) atom. In the third O site, O(9) is bonded in a distorted bent 150 degrees geometry to one K(1), one Si(3), and one Si(4) atom. In the fourth O site, O(10) is bonded in a distorted trigonal planar geometry to one K(1), two equivalent Zn(1), and one Si(2) atom. In the fifth O site, O(1) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the sixth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one K(1), one Si(1), and one Si(2) atom. In the seventh O site, O(3) is bonded in a 3-coordinate geometry to one K(1), one Zn(1), and one Si(4) atom. In the eighth O site, O(4) is bonded in a distorted bent 150 degrees geometry to two equivalent K(1) and two equivalent Si(2) atoms. In the ninth O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(4) atom. In the tenth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one K(1), one Si(1), and one Si(3) atom. is represented by the CIF file [CIF]
data_K2Zn2Si8O19
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.454
_cell_length_b   7.454
_cell_length_c   12.578
_cell_angle_alpha   73.873
_cell_angle_beta   73.873
_cell_angle_gamma   40.536
_symmetry_Int_Tables_number   1
_cell_volume   433.884
_cell_formula_units_Z   1
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  0.591  0.655  0.351  1.0
  K  K1  1  0.345  0.409  0.649  1.0
  Zn  Zn2  1  0.703  0.696  0.589  1.0
  Zn  Zn3  1  0.304  0.297  0.411  1.0
  Si  Si4  1  0.142  0.853  0.167  1.0
  Si  Si5  1  0.923  0.931  0.425  1.0
  Si  Si6  1  0.781  0.471  0.073  1.0
  Si  Si7  1  0.069  0.077  0.575  1.0
  Si  Si8  1  0.613  0.795  0.841  1.0
  Si  Si9  1  0.147  0.858  0.833  1.0
  Si  Si10  1  0.529  0.219  0.927  1.0
  Si  Si11  1  0.205  0.387  0.159  1.0
  O  O12  1  0.803  0.546  0.940  1.0
  O  O13  1  0.454  0.197  0.060  1.0
  O  O14  1  0.095  0.878  0.299  1.0
  O  O15  1  0.289  0.222  0.281  1.0
  O  O16  1  0.122  0.905  0.701  1.0
  O  O17  1  0.094  0.906  0.500  1.0
  O  O18  1  0.109  0.676  0.145  1.0
  O  O19  1  0.457  0.699  0.126  1.0
  O  O20  1  0.919  0.161  0.101  1.0
  O  O21  1  0.301  0.543  0.874  1.0
  O  O22  1  0.603  0.231  0.428  1.0
  O  O23  1  0.930  0.488  0.137  1.0
  O  O24  1  0.965  0.673  0.466  1.0
  O  O25  1  0.324  0.891  0.855  1.0
  O  O26  1  0.839  0.081  0.899  1.0
  O  O27  1  0.769  0.397  0.572  1.0
  O  O28  1  0.778  0.711  0.719  1.0
  O  O29  1  0.327  0.035  0.534  1.0
  O  O30  1  0.512  0.070  0.863  1.0
[/CIF]
.
The crystal structure described by K2Zn2Si8O19 crystallizes in the monoclinic C2 space group. K(1) is bonded in a 8-coordinate geometry to one O(10), one O(2), one O(3), one O(4), one O(6), one O(9), and two equivalent O(8) atoms. Zn(1) is bonded to one O(3), one O(8), and two equivalent O(10) atoms to form ZnO4 tetrahedra that share  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Zn(1)O4 tetrahedra, and corners with three equivalent Si(2)O4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(10), one O(2), one O(4), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with three equivalent Zn(1)O4 tetrahedra. In the third Si site, Si(3) is bonded to one O(1), one O(6), one O(7), and one O(9) atom to form corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(1), one O(3), one O(5), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Zn(1)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. There are ten inequivalent O sites. In the first O site, O(7) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the second O site, O(8) is bonded in a distorted bent 120 degrees geometry to two equivalent K(1), one Zn(1), and one Si(2) atom. In the third O site, O(9) is bonded in a distorted bent 150 degrees geometry to one K(1), one Si(3), and one Si(4) atom. In the fourth O site, O(10) is bonded in a distorted trigonal planar geometry to one K(1), two equivalent Zn(1), and one Si(2) atom. In the fifth O site, O(1) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the sixth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one K(1), one Si(1), and one Si(2) atom. In the seventh O site, O(3) is bonded in a 3-coordinate geometry to one K(1), one Zn(1), and one Si(4) atom. In the eighth O site, O(4) is bonded in a distorted bent 150 degrees geometry to two equivalent K(1) and two equivalent Si(2) atoms. In the ninth O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(4) atom. In the tenth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one K(1), one Si(1), and one Si(3) atom. is represented by the CIF file [CIF]
data_K2Zn2Si8O19
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.454
_cell_length_b   7.454
_cell_length_c   12.578
_cell_angle_alpha   73.873
_cell_angle_beta   73.873
_cell_angle_gamma   40.536
_symmetry_Int_Tables_number   1
_cell_volume   433.884
_cell_formula_units_Z   1
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  0.591  0.655  0.351  1.0
  K  K1  1  0.345  0.409  0.649  1.0
  Zn  Zn2  1  0.703  0.696  0.589  1.0
  Zn  Zn3  1  0.304  0.297  0.411  1.0
  Si  Si4  1  0.142  0.853  0.167  1.0
  Si  Si5  1  0.923  0.931  0.425  1.0
  Si  Si6  1  0.781  0.471  0.073  1.0
  Si  Si7  1  0.069  0.077  0.575  1.0
  Si  Si8  1  0.613  0.795  0.841  1.0
  Si  Si9  1  0.147  0.858  0.833  1.0
  Si  Si10  1  0.529  0.219  0.927  1.0
  Si  Si11  1  0.205  0.387  0.159  1.0
  O  O12  1  0.803  0.546  0.940  1.0
  O  O13  1  0.454  0.197  0.060  1.0
  O  O14  1  0.095  0.878  0.299  1.0
  O  O15  1  0.289  0.222  0.281  1.0
  O  O16  1  0.122  0.905  0.701  1.0
  O  O17  1  0.094  0.906  0.500  1.0
  O  O18  1  0.109  0.676  0.145  1.0
  O  O19  1  0.457  0.699  0.126  1.0
  O  O20  1  0.919  0.161  0.101  1.0
  O  O21  1  0.301  0.543  0.874  1.0
  O  O22  1  0.603  0.231  0.428  1.0
  O  O23  1  0.930  0.488  0.137  1.0
  O  O24  1  0.965  0.673  0.466  1.0
  O  O25  1  0.324  0.891  0.855  1.0
  O  O26  1  0.839  0.081  0.899  1.0
  O  O27  1  0.769  0.397  0.572  1.0
  O  O28  1  0.778  0.711  0.719  1.0
  O  O29  1  0.327  0.035  0.534  1.0
  O  O30  1  0.512  0.070  0.863  1.0
[/CIF]
.