The material structure described by KNb3O8 crystallizes in the orthorhombic Cmcm space group. K(1) is bonded to two equivalent O(1) and four equivalent O(5) atoms to form distorted face-sharing KO6 pentagonal pyramids. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(5), and two equivalent O(4) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent K(1) and two equivalent Nb(2) atoms to form distorted corner-sharing OK2Nb2 tetrahedra. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to two equivalent Nb(1) and two equivalent Nb(2) atoms. In the third O site, O(3) is bonded in a linear geometry to one Nb(1) and one Nb(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Nb(1) and two equivalent Nb(2) atoms. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to two equivalent K(1) and one Nb(2) atom. is represented by the CIF card [CIF]
data_KNb3O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.893
_cell_length_b   10.893
_cell_length_c   9.002
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   159.753
_symmetry_Int_Tables_number   1
_cell_volume   369.685
_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  0.984  0.016  0.750  1.0
  K  K1  1  0.016  0.984  0.250  1.0
  Nb  Nb2  1  0.242  0.758  0.750  1.0
  Nb  Nb3  1  0.758  0.242  0.250  1.0
  Nb  Nb4  1  0.631  0.369  0.558  1.0
  Nb  Nb5  1  0.369  0.631  0.442  1.0
  Nb  Nb6  1  0.369  0.631  0.058  1.0
  Nb  Nb7  1  0.631  0.369  0.942  1.0
  O  O8  1  0.585  0.415  0.750  1.0
  O  O9  1  0.415  0.585  0.250  1.0
  O  O10  1  0.714  0.286  0.750  1.0
  O  O11  1  0.286  0.714  0.250  1.0
  O  O12  1  0.704  0.296  0.407  1.0
  O  O13  1  0.296  0.704  0.593  1.0
  O  O14  1  0.296  0.704  0.907  1.0
  O  O15  1  0.704  0.296  0.093  1.0
  O  O16  1  0.843  0.157  0.408  1.0
  O  O17  1  0.157  0.843  0.592  1.0
  O  O18  1  0.157  0.843  0.908  1.0
  O  O19  1  0.843  0.157  0.092  1.0
  O  O20  1  0.568  0.432  0.067  1.0
  O  O21  1  0.432  0.568  0.933  1.0
  O  O22  1  0.432  0.568  0.567  1.0
  O  O23  1  0.568  0.432  0.433  1.0
[/CIF]
.
The material structure described by KNb3O8 crystallizes in the orthorhombic Cmcm space group. K(1) is bonded to two equivalent O(1) and four equivalent O(5) atoms to form distorted face-sharing KO6 pentagonal pyramids. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(5), and two equivalent O(4) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent K(1) and two equivalent Nb(2) atoms to form distorted corner-sharing OK2Nb2 tetrahedra. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to two equivalent Nb(1) and two equivalent Nb(2) atoms. In the third O site, O(3) is bonded in a linear geometry to one Nb(1) and one Nb(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Nb(1) and two equivalent Nb(2) atoms. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to two equivalent K(1) and one Nb(2) atom. is represented by the CIF card [CIF]
data_KNb3O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.893
_cell_length_b   10.893
_cell_length_c   9.002
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   159.753
_symmetry_Int_Tables_number   1
_cell_volume   369.685
_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  0.984  0.016  0.750  1.0
  K  K1  1  0.016  0.984  0.250  1.0
  Nb  Nb2  1  0.242  0.758  0.750  1.0
  Nb  Nb3  1  0.758  0.242  0.250  1.0
  Nb  Nb4  1  0.631  0.369  0.558  1.0
  Nb  Nb5  1  0.369  0.631  0.442  1.0
  Nb  Nb6  1  0.369  0.631  0.058  1.0
  Nb  Nb7  1  0.631  0.369  0.942  1.0
  O  O8  1  0.585  0.415  0.750  1.0
  O  O9  1  0.415  0.585  0.250  1.0
  O  O10  1  0.714  0.286  0.750  1.0
  O  O11  1  0.286  0.714  0.250  1.0
  O  O12  1  0.704  0.296  0.407  1.0
  O  O13  1  0.296  0.704  0.593  1.0
  O  O14  1  0.296  0.704  0.907  1.0
  O  O15  1  0.704  0.296  0.093  1.0
  O  O16  1  0.843  0.157  0.408  1.0
  O  O17  1  0.157  0.843  0.592  1.0
  O  O18  1  0.157  0.843  0.908  1.0
  O  O19  1  0.843  0.157  0.092  1.0
  O  O20  1  0.568  0.432  0.067  1.0
  O  O21  1  0.432  0.568  0.933  1.0
  O  O22  1  0.432  0.568  0.567  1.0
  O  O23  1  0.568  0.432  0.433  1.0
[/CIF]
.