The crystal structure described by K4Nb2Si8O23 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 4-coordinate geometry to one O(2), one O(6), and two equivalent O(7) atoms. In the second K site, K(2) is bonded in a 2-coordinate geometry to one O(6) and one O(7) atom. Nb(1) is bonded to one O(12), one O(4), one O(5), one O(6), one O(7), and one O(9) atom to form distorted NbO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(11), one O(3), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 47°. In the second Si site, Si(2) is bonded to one O(11), one O(12), one O(2), and one O(5) atom to form SiO4 tetrahedra that share corners with two equivalent Nb(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 30-38°. In the third Si site, Si(3) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. In the fourth Si site, Si(4) is bonded to one O(1), one O(10), one O(8), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 17°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one K(1), one Si(2), and one Si(3) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(3) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Nb(1) and one Si(3) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Nb(1) and one Si(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one K(1), one K(2), one Nb(1), and one Si(1) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one Nb(1) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Si(1) and one Si(4) atom. In the ninth O site, O(9) is bonded in a 2-coordinate geometry to one Nb(1) and one Si(4) atom. In the tenth O site, O(10) is bonded in a linear geometry to two equivalent Si(4) atoms. In the eleventh O site, O(11) is bonded in a distorted linear geometry to one Si(1) and one Si(2) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one Nb(1) and one Si(2) atom. is represented by the CIF file [CIF]
data_K4Nb2Si8O23
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.883
_cell_length_b   7.963
_cell_length_c   11.163
_cell_angle_alpha   104.083
_cell_angle_beta   89.202
_cell_angle_gamma   107.924
_symmetry_Int_Tables_number   1
_cell_volume   563.420
_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  0.278  0.244  0.481  1.0
  K  K1  1  0.722  0.756  0.519  1.0
  K  K2  1  0.333  0.299  0.148  1.0
  K  K3  1  0.667  0.701  0.852  1.0
  Nb  Nb4  1  0.785  0.273  0.310  1.0
  Nb  Nb5  1  0.215  0.727  0.690  1.0
  Si  Si6  1  0.970  0.894  0.212  1.0
  Si  Si7  1  0.030  0.106  0.788  1.0
  Si  Si8  1  0.173  0.696  0.376  1.0
  Si  Si9  1  0.827  0.304  0.624  1.0
  Si  Si10  1  0.514  0.818  0.215  1.0
  Si  Si11  1  0.486  0.182  0.785  1.0
  Si  Si12  1  0.169  0.696  0.005  1.0
  Si  Si13  1  0.831  0.304  0.995  1.0
  O  O14  1  0.375  0.709  0.084  1.0
  O  O15  1  0.625  0.291  0.916  1.0
  O  O16  1  0.406  0.722  0.325  1.0
  O  O17  1  0.594  0.278  0.675  1.0
  O  O18  1  0.727  0.769  0.190  1.0
  O  O19  1  0.273  0.231  0.810  1.0
  O  O20  1  0.548  0.034  0.254  1.0
  O  O21  1  0.452  0.966  0.746  1.0
  O  O22  1  0.051  0.479  0.338  1.0
  O  O23  1  0.949  0.521  0.662  1.0
  O  O24  1  0.002  0.108  0.261  1.0
  O  O25  1  0.998  0.892  0.739  1.0
  O  O26  1  0.614  0.404  0.363  1.0
  O  O27  1  0.386  0.596  0.637  1.0
  O  O28  1  0.074  0.855  0.078  1.0
  O  O29  1  0.926  0.145  0.922  1.0
  O  O30  1  0.770  0.283  0.131  1.0
  O  O31  1  0.230  0.717  0.869  1.0
  O  O32  1  0.000  0.500  0.000  1.0
  O  O33  1  0.069  0.815  0.311  1.0
  O  O34  1  0.931  0.185  0.689  1.0
  O  O35  1  0.818  0.218  0.476  1.0
  O  O36  1  0.182  0.782  0.524  1.0
[/CIF]
.
The crystal structure described by K4Nb2Si8O23 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 4-coordinate geometry to one O(2), one O(6), and two equivalent O(7) atoms. In the second K site, K(2) is bonded in a 2-coordinate geometry to one O(6) and one O(7) atom. Nb(1) is bonded to one O(12), one O(4), one O(5), one O(6), one O(7), and one O(9) atom to form distorted NbO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(11), one O(3), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 47°. In the second Si site, Si(2) is bonded to one O(11), one O(12), one O(2), and one O(5) atom to form SiO4 tetrahedra that share corners with two equivalent Nb(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 30-38°. In the third Si site, Si(3) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. In the fourth Si site, Si(4) is bonded to one O(1), one O(10), one O(8), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 17°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one K(1), one Si(2), and one Si(3) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(3) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Nb(1) and one Si(3) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Nb(1) and one Si(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one K(1), one K(2), one Nb(1), and one Si(1) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one Nb(1) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Si(1) and one Si(4) atom. In the ninth O site, O(9) is bonded in a 2-coordinate geometry to one Nb(1) and one Si(4) atom. In the tenth O site, O(10) is bonded in a linear geometry to two equivalent Si(4) atoms. In the eleventh O site, O(11) is bonded in a distorted linear geometry to one Si(1) and one Si(2) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one Nb(1) and one Si(2) atom. is represented by the CIF file [CIF]
data_K4Nb2Si8O23
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.883
_cell_length_b   7.963
_cell_length_c   11.163
_cell_angle_alpha   104.083
_cell_angle_beta   89.202
_cell_angle_gamma   107.924
_symmetry_Int_Tables_number   1
_cell_volume   563.420
_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  0.278  0.244  0.481  1.0
  K  K1  1  0.722  0.756  0.519  1.0
  K  K2  1  0.333  0.299  0.148  1.0
  K  K3  1  0.667  0.701  0.852  1.0
  Nb  Nb4  1  0.785  0.273  0.310  1.0
  Nb  Nb5  1  0.215  0.727  0.690  1.0
  Si  Si6  1  0.970  0.894  0.212  1.0
  Si  Si7  1  0.030  0.106  0.788  1.0
  Si  Si8  1  0.173  0.696  0.376  1.0
  Si  Si9  1  0.827  0.304  0.624  1.0
  Si  Si10  1  0.514  0.818  0.215  1.0
  Si  Si11  1  0.486  0.182  0.785  1.0
  Si  Si12  1  0.169  0.696  0.005  1.0
  Si  Si13  1  0.831  0.304  0.995  1.0
  O  O14  1  0.375  0.709  0.084  1.0
  O  O15  1  0.625  0.291  0.916  1.0
  O  O16  1  0.406  0.722  0.325  1.0
  O  O17  1  0.594  0.278  0.675  1.0
  O  O18  1  0.727  0.769  0.190  1.0
  O  O19  1  0.273  0.231  0.810  1.0
  O  O20  1  0.548  0.034  0.254  1.0
  O  O21  1  0.452  0.966  0.746  1.0
  O  O22  1  0.051  0.479  0.338  1.0
  O  O23  1  0.949  0.521  0.662  1.0
  O  O24  1  0.002  0.108  0.261  1.0
  O  O25  1  0.998  0.892  0.739  1.0
  O  O26  1  0.614  0.404  0.363  1.0
  O  O27  1  0.386  0.596  0.637  1.0
  O  O28  1  0.074  0.855  0.078  1.0
  O  O29  1  0.926  0.145  0.922  1.0
  O  O30  1  0.770  0.283  0.131  1.0
  O  O31  1  0.230  0.717  0.869  1.0
  O  O32  1  0.000  0.500  0.000  1.0
  O  O33  1  0.069  0.815  0.311  1.0
  O  O34  1  0.931  0.185  0.689  1.0
  O  O35  1  0.818  0.218  0.476  1.0
  O  O36  1  0.182  0.782  0.524  1.0
[/CIF]
.