The compound described by K3Nb8(O5F2)2 crystallizes in the tetragonal P4mm space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 9-coordinate geometry to four equivalent O(1), one F(3), and four equivalent F(1) atoms. In the second K site, K(2) is bonded in a 9-coordinate geometry to four equivalent O(2), one F(4), and four equivalent F(2) atoms. In the third K site, K(3) is bonded in a 9-coordinate geometry to four equivalent O(4), one F(1), and four equivalent F(3) atoms. There are six inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to four equivalent O(1) and one F(1) atom to form corner-sharing NbO4F square pyramids. In the second Nb site, Nb(2) is bonded to four equivalent O(2) and one F(2) atom to form corner-sharing NbO4F square pyramids. In the third Nb site, Nb(3) is bonded in a square co-planar geometry to one O(4), one O(5), and two equivalent O(6) atoms. In the fourth Nb site, Nb(4) is bonded to four equivalent O(4) and one F(3) atom to form corner-sharing NbO4F square pyramids. In the fifth Nb site, Nb(5) is bonded to four equivalent O(5) and one F(4) atom to form corner-sharing NbO4F square pyramids. In the sixth Nb site, Nb(6) is bonded in a square co-planar geometry to one O(1), one O(2), and two equivalent O(3) atoms. There are six inequivalent O sites. In the first O site, O(1) is bonded to two equivalent K(1), one Nb(6), and two equivalent Nb(1) atoms to form distorted OK2Nb3 trigonal bipyramids that share corners with two equivalent F(3)K5Nb octahedra, corners with four equivalent F(1)K5Nb octahedra, corners with four equivalent O(1)K2Nb3 trigonal bipyramids, edges with four equivalent O(1)K2Nb3 trigonal bipyramids, and faces with two equivalent F(1)K5Nb octahedra. The corner-sharing octahedral tilt angles range from 47-56°. In the second O site, O(2) is bonded in a distorted T-shaped geometry to two equivalent K(2), one Nb(6), and two equivalent Nb(2) atoms. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to four equivalent Nb(6) atoms. In the fourth O site, O(4) is bonded to two equivalent K(3), one Nb(3), and two equivalent Nb(4) atoms to form distorted OK2Nb3 trigonal bipyramids that share corners with two equivalent F(1)K5Nb octahedra, corners with four equivalent F(3)K5Nb octahedra, corners with four equivalent O(4)K2Nb3 trigonal bipyramids, edges with four equivalent O(4)K2Nb3 trigonal bipyramids, and faces with two equivalent F(3)K5Nb octahedra. The corner-sharing octahedral tilt angles range from 47-56°. In the fifth O site, O(5) is bonded in a T-shaped geometry to one Nb(3) and two equivalent Nb(5) atoms. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to four equivalent Nb(3) atoms. There are four inequivalent F sites. In the first F site, F(1) is bonded to one K(3), four equivalent K(1), and one Nb(1) atom to form FK5Nb octahedra that share corners with four equivalent F(1)K5Nb octahedra, corners with four equivalent O(4)K2Nb3 trigonal bipyramids, corners with eight equivalent O(1)K2Nb3 trigonal bipyramids, edges with four equivalent F(1)K5Nb octahedra, edges with four equivalent F(3)K5Nb octahedra, and faces with four equivalent O(1)K2Nb3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 7°. In the second F site, F(2) is bonded to four equivalent K(2) and one Nb(2) atom to form a mixture of distorted corner and edge-sharing FK4Nb square pyramids. In the third F site, F(3) is bonded to one K(1), four equivalent K(3), and one Nb(4) atom to form FK5Nb octahedra that share corners with four equivalent F(3)K5Nb octahedra, corners with four equivalent O(1)K2Nb3 trigonal bipyramids, corners with eight equivalent O(4)K2Nb3 trigonal bipyramids, edges with four equivalent F(1)K5Nb octahedra, edges with four equivalent F(3)K5Nb octahedra, and faces with four equivalent O(4)K2Nb3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 6°. In the fourth F site, F(4) is bonded in a linear geometry to one K(2) and one Nb(5) atom. is represented by the CIF card [CIF]
data_K3Nb8(O5F2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.196
_cell_length_b   4.196
_cell_length_c   21.958
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   386.618
_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  0.500  0.500  0.686  1.0
  K  K1  1  0.500  0.500  0.304  1.0
  K  K2  1  0.000  0.000  0.814  1.0
  Nb  Nb3  1  0.000  0.000  0.593  1.0
  Nb  Nb4  1  0.000  0.000  0.406  1.0
  Nb  Nb5  1  0.000  0.500  0.000  1.0
  Nb  Nb6  1  0.500  0.000  0.000  1.0
  Nb  Nb7  1  0.500  0.500  0.908  1.0
  Nb  Nb8  1  0.500  0.500  0.100  1.0
  Nb  Nb9  1  0.000  0.500  0.500  1.0
  Nb  Nb10  1  0.500  0.000  0.500  1.0
  O  O11  1  0.000  0.500  0.597  1.0
  O  O12  1  0.500  0.000  0.597  1.0
  O  O13  1  0.000  0.500  0.403  1.0
  O  O14  1  0.500  0.000  0.403  1.0
  O  O15  1  0.500  0.500  0.500  1.0
  O  O16  1  0.500  0.000  0.903  1.0
  O  O17  1  0.000  0.500  0.903  1.0
  O  O18  1  0.500  0.000  0.095  1.0
  O  O19  1  0.000  0.500  0.095  1.0
  O  O20  1  0.000  0.000  0.000  1.0
  F  F21  1  0.000  0.000  0.694  1.0
  F  F22  1  0.000  0.000  0.310  1.0
  F  F23  1  0.500  0.500  0.806  1.0
  F  F24  1  0.500  0.500  0.191  1.0
[/CIF]
.
The compound described by K3Nb8(O5F2)2 crystallizes in the tetragonal P4mm space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 9-coordinate geometry to four equivalent O(1), one F(3), and four equivalent F(1) atoms. In the second K site, K(2) is bonded in a 9-coordinate geometry to four equivalent O(2), one F(4), and four equivalent F(2) atoms. In the third K site, K(3) is bonded in a 9-coordinate geometry to four equivalent O(4), one F(1), and four equivalent F(3) atoms. There are six inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to four equivalent O(1) and one F(1) atom to form corner-sharing NbO4F square pyramids. In the second Nb site, Nb(2) is bonded to four equivalent O(2) and one F(2) atom to form corner-sharing NbO4F square pyramids. In the third Nb site, Nb(3) is bonded in a square co-planar geometry to one O(4), one O(5), and two equivalent O(6) atoms. In the fourth Nb site, Nb(4) is bonded to four equivalent O(4) and one F(3) atom to form corner-sharing NbO4F square pyramids. In the fifth Nb site, Nb(5) is bonded to four equivalent O(5) and one F(4) atom to form corner-sharing NbO4F square pyramids. In the sixth Nb site, Nb(6) is bonded in a square co-planar geometry to one O(1), one O(2), and two equivalent O(3) atoms. There are six inequivalent O sites. In the first O site, O(1) is bonded to two equivalent K(1), one Nb(6), and two equivalent Nb(1) atoms to form distorted OK2Nb3 trigonal bipyramids that share corners with two equivalent F(3)K5Nb octahedra, corners with four equivalent F(1)K5Nb octahedra, corners with four equivalent O(1)K2Nb3 trigonal bipyramids, edges with four equivalent O(1)K2Nb3 trigonal bipyramids, and faces with two equivalent F(1)K5Nb octahedra. The corner-sharing octahedral tilt angles range from 47-56°. In the second O site, O(2) is bonded in a distorted T-shaped geometry to two equivalent K(2), one Nb(6), and two equivalent Nb(2) atoms. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to four equivalent Nb(6) atoms. In the fourth O site, O(4) is bonded to two equivalent K(3), one Nb(3), and two equivalent Nb(4) atoms to form distorted OK2Nb3 trigonal bipyramids that share corners with two equivalent F(1)K5Nb octahedra, corners with four equivalent F(3)K5Nb octahedra, corners with four equivalent O(4)K2Nb3 trigonal bipyramids, edges with four equivalent O(4)K2Nb3 trigonal bipyramids, and faces with two equivalent F(3)K5Nb octahedra. The corner-sharing octahedral tilt angles range from 47-56°. In the fifth O site, O(5) is bonded in a T-shaped geometry to one Nb(3) and two equivalent Nb(5) atoms. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to four equivalent Nb(3) atoms. There are four inequivalent F sites. In the first F site, F(1) is bonded to one K(3), four equivalent K(1), and one Nb(1) atom to form FK5Nb octahedra that share corners with four equivalent F(1)K5Nb octahedra, corners with four equivalent O(4)K2Nb3 trigonal bipyramids, corners with eight equivalent O(1)K2Nb3 trigonal bipyramids, edges with four equivalent F(1)K5Nb octahedra, edges with four equivalent F(3)K5Nb octahedra, and faces with four equivalent O(1)K2Nb3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 7°. In the second F site, F(2) is bonded to four equivalent K(2) and one Nb(2) atom to form a mixture of distorted corner and edge-sharing FK4Nb square pyramids. In the third F site, F(3) is bonded to one K(1), four equivalent K(3), and one Nb(4) atom to form FK5Nb octahedra that share corners with four equivalent F(3)K5Nb octahedra, corners with four equivalent O(1)K2Nb3 trigonal bipyramids, corners with eight equivalent O(4)K2Nb3 trigonal bipyramids, edges with four equivalent F(1)K5Nb octahedra, edges with four equivalent F(3)K5Nb octahedra, and faces with four equivalent O(4)K2Nb3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 6°. In the fourth F site, F(4) is bonded in a linear geometry to one K(2) and one Nb(5) atom. is represented by the CIF card [CIF]
data_K3Nb8(O5F2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.196
_cell_length_b   4.196
_cell_length_c   21.958
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   386.618
_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  0.500  0.500  0.686  1.0
  K  K1  1  0.500  0.500  0.304  1.0
  K  K2  1  0.000  0.000  0.814  1.0
  Nb  Nb3  1  0.000  0.000  0.593  1.0
  Nb  Nb4  1  0.000  0.000  0.406  1.0
  Nb  Nb5  1  0.000  0.500  0.000  1.0
  Nb  Nb6  1  0.500  0.000  0.000  1.0
  Nb  Nb7  1  0.500  0.500  0.908  1.0
  Nb  Nb8  1  0.500  0.500  0.100  1.0
  Nb  Nb9  1  0.000  0.500  0.500  1.0
  Nb  Nb10  1  0.500  0.000  0.500  1.0
  O  O11  1  0.000  0.500  0.597  1.0
  O  O12  1  0.500  0.000  0.597  1.0
  O  O13  1  0.000  0.500  0.403  1.0
  O  O14  1  0.500  0.000  0.403  1.0
  O  O15  1  0.500  0.500  0.500  1.0
  O  O16  1  0.500  0.000  0.903  1.0
  O  O17  1  0.000  0.500  0.903  1.0
  O  O18  1  0.500  0.000  0.095  1.0
  O  O19  1  0.000  0.500  0.095  1.0
  O  O20  1  0.000  0.000  0.000  1.0
  F  F21  1  0.000  0.000  0.694  1.0
  F  F22  1  0.000  0.000  0.310  1.0
  F  F23  1  0.500  0.500  0.806  1.0
  F  F24  1  0.500  0.500  0.191  1.0
[/CIF]
.