The material described by Bi5KNb4O18 crystallizes in the monoclinic Cm space group. K(1) is bonded in a 10-coordinate geometry to two equivalent O(10), two equivalent O(4), two equivalent O(7), two equivalent O(8), and two equivalent O(9) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(3), one O(4), one O(7), one O(8), and one O(9) atom to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 20-30°. In the second Nb site, Nb(2) is bonded to one O(10), one O(2), one O(3), one O(4), one O(7), and one O(8) atom to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 19-30°. There are three inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 4-coordinate geometry to one O(10), one O(9), and two equivalent O(3) atoms. In the second Bi site, Bi(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(5), and two equivalent O(6) atoms. In the third Bi site, Bi(3) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(5), and two equivalent O(6) atoms. There are ten inequivalent O sites. In the first O site, O(7) is bonded in a 3-coordinate geometry to one K(1), one Nb(1), and one Nb(2) atom. In the second O site, O(8) is bonded in a distorted bent 150 degrees geometry to one K(1), one Nb(1), and one Nb(2) atom. In the third O site, O(9) is bonded in a 5-coordinate geometry to two equivalent K(1), two equivalent Nb(1), and one Bi(1) atom. In the fourth O site, O(10) is bonded to two equivalent K(1), two equivalent Nb(2), and one Bi(1) atom to form distorted corner-sharing OK2Nb2Bi square pyramids. In the fifth O site, O(1) is bonded in a distorted single-bond geometry to one Nb(1), one Bi(2), and one Bi(3) atom. In the sixth O site, O(2) is bonded in a distorted single-bond geometry to one Nb(2), one Bi(2), and one Bi(3) atom. In the seventh O site, O(3) is bonded in a 3-coordinate geometry to one Nb(1), one Nb(2), and one Bi(1) atom. In the eighth O site, O(4) is bonded in a distorted T-shaped geometry to one K(1), one Nb(1), and one Nb(2) atom. In the ninth O site, O(5) is bonded to two equivalent Bi(2) and two equivalent Bi(3) atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. In the tenth O site, O(6) is bonded to two equivalent Bi(2) and two equivalent Bi(3) atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. is represented by the CIF card [CIF]
data_KNb4Bi5O18
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.946
_cell_length_b   12.946
_cell_length_c   5.616
_cell_angle_alpha   89.779
_cell_angle_beta   89.779
_cell_angle_gamma   154.983
_symmetry_Int_Tables_number   1
_cell_volume   397.937
_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  0.738  0.738  0.530  1.0
  Nb  Nb1  1  0.824  0.650  0.040  1.0
  Nb  Nb2  1  0.650  0.824  0.040  1.0
  Nb  Nb3  1  0.156  0.331  0.535  1.0
  Nb  Nb4  1  0.331  0.156  0.535  1.0
  Bi  Bi5  1  0.203  0.203  0.987  1.0
  Bi  Bi6  1  0.082  0.484  0.997  1.0
  Bi  Bi7  1  0.484  0.082  0.997  1.0
  Bi  Bi8  1  0.918  0.517  0.496  1.0
  Bi  Bi9  1  0.517  0.918  0.496  1.0
  O  O10  1  0.854  0.532  0.069  1.0
  O  O11  1  0.532  0.854  0.069  1.0
  O  O12  1  0.154  0.475  0.570  1.0
  O  O13  1  0.475  0.154  0.570  1.0
  O  O14  1  0.968  0.135  0.859  1.0
  O  O15  1  0.135  0.968  0.859  1.0
  O  O16  1  0.057  0.876  0.349  1.0
  O  O17  1  0.876  0.057  0.349  1.0
  O  O18  1  0.764  0.259  0.773  1.0
  O  O19  1  0.259  0.764  0.773  1.0
  O  O20  1  0.240  0.744  0.273  1.0
  O  O21  1  0.744  0.240  0.273  1.0
  O  O22  1  0.459  0.610  0.784  1.0
  O  O23  1  0.610  0.459  0.784  1.0
  O  O24  1  0.539  0.397  0.277  1.0
  O  O25  1  0.397  0.539  0.277  1.0
  O  O26  1  0.815  0.815  0.055  1.0
  O  O27  1  0.218  0.218  0.595  1.0
[/CIF]
.
The material described by Bi5KNb4O18 crystallizes in the monoclinic Cm space group. K(1) is bonded in a 10-coordinate geometry to two equivalent O(10), two equivalent O(4), two equivalent O(7), two equivalent O(8), and two equivalent O(9) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(3), one O(4), one O(7), one O(8), and one O(9) atom to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 20-30°. In the second Nb site, Nb(2) is bonded to one O(10), one O(2), one O(3), one O(4), one O(7), and one O(8) atom to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 19-30°. There are three inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 4-coordinate geometry to one O(10), one O(9), and two equivalent O(3) atoms. In the second Bi site, Bi(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(5), and two equivalent O(6) atoms. In the third Bi site, Bi(3) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(5), and two equivalent O(6) atoms. There are ten inequivalent O sites. In the first O site, O(7) is bonded in a 3-coordinate geometry to one K(1), one Nb(1), and one Nb(2) atom. In the second O site, O(8) is bonded in a distorted bent 150 degrees geometry to one K(1), one Nb(1), and one Nb(2) atom. In the third O site, O(9) is bonded in a 5-coordinate geometry to two equivalent K(1), two equivalent Nb(1), and one Bi(1) atom. In the fourth O site, O(10) is bonded to two equivalent K(1), two equivalent Nb(2), and one Bi(1) atom to form distorted corner-sharing OK2Nb2Bi square pyramids. In the fifth O site, O(1) is bonded in a distorted single-bond geometry to one Nb(1), one Bi(2), and one Bi(3) atom. In the sixth O site, O(2) is bonded in a distorted single-bond geometry to one Nb(2), one Bi(2), and one Bi(3) atom. In the seventh O site, O(3) is bonded in a 3-coordinate geometry to one Nb(1), one Nb(2), and one Bi(1) atom. In the eighth O site, O(4) is bonded in a distorted T-shaped geometry to one K(1), one Nb(1), and one Nb(2) atom. In the ninth O site, O(5) is bonded to two equivalent Bi(2) and two equivalent Bi(3) atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. In the tenth O site, O(6) is bonded to two equivalent Bi(2) and two equivalent Bi(3) atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. is represented by the CIF card [CIF]
data_KNb4Bi5O18
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.946
_cell_length_b   12.946
_cell_length_c   5.616
_cell_angle_alpha   89.779
_cell_angle_beta   89.779
_cell_angle_gamma   154.983
_symmetry_Int_Tables_number   1
_cell_volume   397.937
_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  0.738  0.738  0.530  1.0
  Nb  Nb1  1  0.824  0.650  0.040  1.0
  Nb  Nb2  1  0.650  0.824  0.040  1.0
  Nb  Nb3  1  0.156  0.331  0.535  1.0
  Nb  Nb4  1  0.331  0.156  0.535  1.0
  Bi  Bi5  1  0.203  0.203  0.987  1.0
  Bi  Bi6  1  0.082  0.484  0.997  1.0
  Bi  Bi7  1  0.484  0.082  0.997  1.0
  Bi  Bi8  1  0.918  0.517  0.496  1.0
  Bi  Bi9  1  0.517  0.918  0.496  1.0
  O  O10  1  0.854  0.532  0.069  1.0
  O  O11  1  0.532  0.854  0.069  1.0
  O  O12  1  0.154  0.475  0.570  1.0
  O  O13  1  0.475  0.154  0.570  1.0
  O  O14  1  0.968  0.135  0.859  1.0
  O  O15  1  0.135  0.968  0.859  1.0
  O  O16  1  0.057  0.876  0.349  1.0
  O  O17  1  0.876  0.057  0.349  1.0
  O  O18  1  0.764  0.259  0.773  1.0
  O  O19  1  0.259  0.764  0.773  1.0
  O  O20  1  0.240  0.744  0.273  1.0
  O  O21  1  0.744  0.240  0.273  1.0
  O  O22  1  0.459  0.610  0.784  1.0
  O  O23  1  0.610  0.459  0.784  1.0
  O  O24  1  0.539  0.397  0.277  1.0
  O  O25  1  0.397  0.539  0.277  1.0
  O  O26  1  0.815  0.815  0.055  1.0
  O  O27  1  0.218  0.218  0.595  1.0
[/CIF]
.