The material described by K2Nb2O5 crystallizes in the orthorhombic Ima2 space group. K(1) is bonded in a 9-coordinate geometry to one O(3), four equivalent O(1), and four equivalent O(2) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NbO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra and corners with two equivalent Nb(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 2°. In the second Nb site, Nb(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form NbO4 tetrahedra that share corners with two equivalent Nb(1)O6 octahedra and corners with two equivalent Nb(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 15°. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent K(1) and two equivalent Nb(1) atoms to form distorted OK4Nb2 octahedra that share corners with two equivalent O(1)K4Nb2 octahedra, corners with four equivalent O(3)K2Nb2 tetrahedra, edges with two equivalent O(1)K4Nb2 octahedra, and faces with four equivalent O(1)K4Nb2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent K(1), one Nb(1), and one Nb(2) atom. In the third O site, O(3) is bonded to two equivalent K(1) and two equivalent Nb(2) atoms to form distorted OK2Nb2 tetrahedra that share corners with eight equivalent O(1)K4Nb2 octahedra and corners with two equivalent O(3)K2Nb2 tetrahedra. The corner-sharing octahedral tilt angles range from 17-82°. is represented by the CIF file [CIF]
data_K2Nb2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.050
_cell_length_b   9.050
_cell_length_c   9.050
_cell_angle_alpha   142.362
_cell_angle_beta   141.992
_cell_angle_gamma   54.563
_symmetry_Int_Tables_number   1
_cell_volume   276.808
_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  0.388  0.866  0.476  1.0
  K  K1  1  0.610  0.134  0.522  1.0
  K  K2  1  0.888  0.411  0.522  1.0
  K  K3  1  0.110  0.589  0.476  1.0
  Nb  Nb4  1  0.994  0.000  0.994  1.0
  Nb  Nb5  1  0.494  0.500  0.994  1.0
  Nb  Nb6  1  0.765  0.829  0.094  1.0
  Nb  Nb7  1  0.265  0.171  0.937  1.0
  O  O8  1  0.750  0.753  0.499  1.0
  O  O9  1  0.746  0.247  0.997  1.0
  O  O10  1  0.250  0.751  0.997  1.0
  O  O11  1  0.246  0.249  0.499  1.0
  O  O12  1  0.863  0.865  0.992  1.0
  O  O13  1  0.128  0.135  0.999  1.0
  O  O14  1  0.363  0.371  0.999  1.0
  O  O15  1  0.628  0.629  0.992  1.0
  O  O16  1  0.092  0.888  0.479  1.0
  O  O17  1  0.592  0.112  0.204  1.0
[/CIF]
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The material described by K2Nb2O5 crystallizes in the orthorhombic Ima2 space group. K(1) is bonded in a 9-coordinate geometry to one O(3), four equivalent O(1), and four equivalent O(2) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NbO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra and corners with two equivalent Nb(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 2°. In the second Nb site, Nb(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form NbO4 tetrahedra that share corners with two equivalent Nb(1)O6 octahedra and corners with two equivalent Nb(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 15°. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent K(1) and two equivalent Nb(1) atoms to form distorted OK4Nb2 octahedra that share corners with two equivalent O(1)K4Nb2 octahedra, corners with four equivalent O(3)K2Nb2 tetrahedra, edges with two equivalent O(1)K4Nb2 octahedra, and faces with four equivalent O(1)K4Nb2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent K(1), one Nb(1), and one Nb(2) atom. In the third O site, O(3) is bonded to two equivalent K(1) and two equivalent Nb(2) atoms to form distorted OK2Nb2 tetrahedra that share corners with eight equivalent O(1)K4Nb2 octahedra and corners with two equivalent O(3)K2Nb2 tetrahedra. The corner-sharing octahedral tilt angles range from 17-82°. is represented by the CIF file [CIF]
data_K2Nb2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.050
_cell_length_b   9.050
_cell_length_c   9.050
_cell_angle_alpha   142.362
_cell_angle_beta   141.992
_cell_angle_gamma   54.563
_symmetry_Int_Tables_number   1
_cell_volume   276.808
_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  0.388  0.866  0.476  1.0
  K  K1  1  0.610  0.134  0.522  1.0
  K  K2  1  0.888  0.411  0.522  1.0
  K  K3  1  0.110  0.589  0.476  1.0
  Nb  Nb4  1  0.994  0.000  0.994  1.0
  Nb  Nb5  1  0.494  0.500  0.994  1.0
  Nb  Nb6  1  0.765  0.829  0.094  1.0
  Nb  Nb7  1  0.265  0.171  0.937  1.0
  O  O8  1  0.750  0.753  0.499  1.0
  O  O9  1  0.746  0.247  0.997  1.0
  O  O10  1  0.250  0.751  0.997  1.0
  O  O11  1  0.246  0.249  0.499  1.0
  O  O12  1  0.863  0.865  0.992  1.0
  O  O13  1  0.128  0.135  0.999  1.0
  O  O14  1  0.363  0.371  0.999  1.0
  O  O15  1  0.628  0.629  0.992  1.0
  O  O16  1  0.092  0.888  0.479  1.0
  O  O17  1  0.592  0.112  0.204  1.0
[/CIF]
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