The compound described by K2DyNb5O15 crystallizes in the tetragonal P4/mbm space group. K(1) is bonded in a 9-coordinate geometry to one O(3), two equivalent O(1), two equivalent O(2), and four equivalent O(5) atoms. Dy(1) is bonded to four equivalent O(1) and eight equivalent O(4) atoms to form DyO12 cuboctahedra that share faces with two equivalent Dy(1)O12 cuboctahedra and faces with eight equivalent Nb(2)O6 octahedra. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(3) and four equivalent O(5) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 0-31°. In the second Nb site, Nb(2) is bonded to one O(2), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with five equivalent Nb(2)O6 octahedra, and faces with two equivalent Dy(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 12-37°. There are five inequivalent O sites. In the first O site, O(5) is bonded in a distorted bent 150 degrees geometry to two equivalent K(1), one Nb(1), and one Nb(2) atom. In the second O site, O(1) is bonded in a 2-coordinate geometry to one K(1), one Dy(1), and two equivalent Nb(2) atoms. In the third O site, O(2) is bonded in a 4-coordinate geometry to two equivalent K(1) and two equivalent Nb(2) atoms. In the fourth O site, O(3) is bonded in a linear geometry to two equivalent K(1) and two equivalent Nb(1) atoms. In the fifth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Dy(1) and two equivalent Nb(2) atoms. is represented by the CIF file [CIF]
data_K2DyNb5O15
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.751
_cell_length_b   12.751
_cell_length_c   3.954
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   642.843
_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  0.670  0.170  0.500  1.0
  K  K1  1  0.330  0.830  0.500  1.0
  K  K2  1  0.170  0.330  0.500  1.0
  K  K3  1  0.830  0.670  0.500  1.0
  Dy  Dy4  1  0.000  0.000  0.500  1.0
  Dy  Dy5  1  0.500  0.500  0.500  1.0
  Nb  Nb6  1  0.500  0.000  0.000  1.0
  Nb  Nb7  1  0.000  0.500  0.000  1.0
  Nb  Nb8  1  0.212  0.077  0.000  1.0
  Nb  Nb9  1  0.788  0.923  0.000  1.0
  Nb  Nb10  1  0.077  0.788  0.000  1.0
  Nb  Nb11  1  0.712  0.423  0.000  1.0
  Nb  Nb12  1  0.923  0.212  0.000  1.0
  Nb  Nb13  1  0.288  0.577  0.000  1.0
  Nb  Nb14  1  0.577  0.712  0.000  1.0
  Nb  Nb15  1  0.423  0.288  0.000  1.0
  O  O16  1  0.185  0.078  0.500  1.0
  O  O17  1  0.815  0.922  0.500  1.0
  O  O18  1  0.078  0.815  0.500  1.0
  O  O19  1  0.685  0.422  0.500  1.0
  O  O20  1  0.922  0.185  0.500  1.0
  O  O21  1  0.315  0.578  0.500  1.0
  O  O22  1  0.578  0.685  0.500  1.0
  O  O23  1  0.422  0.315  0.500  1.0
  O  O24  1  0.217  0.717  0.000  1.0
  O  O25  1  0.783  0.283  0.000  1.0
  O  O26  1  0.717  0.783  0.000  1.0
  O  O27  1  0.283  0.217  0.000  1.0
  O  O28  1  0.500  0.000  0.500  1.0
  O  O29  1  0.000  0.500  0.500  1.0
  O  O30  1  0.058  0.131  0.000  1.0
  O  O31  1  0.942  0.869  0.000  1.0
  O  O32  1  0.131  0.942  0.000  1.0
  O  O33  1  0.558  0.369  0.000  1.0
  O  O34  1  0.869  0.058  0.000  1.0
  O  O35  1  0.442  0.631  0.000  1.0
  O  O36  1  0.631  0.558  0.000  1.0
  O  O37  1  0.369  0.442  0.000  1.0
  O  O38  1  0.342  1.000  0.000  1.0
  O  O39  1  0.658  0.000  0.000  1.0
  O  O40  1  1.000  0.658  0.000  1.0
  O  O41  1  0.842  0.500  0.000  1.0
  O  O42  1  0.000  0.342  0.000  1.0
  O  O43  1  0.158  0.500  0.000  1.0
  O  O44  1  0.500  0.842  0.000  1.0
  O  O45  1  0.500  0.158  0.000  1.0
[/CIF]
.
The compound described by K2DyNb5O15 crystallizes in the tetragonal P4/mbm space group. K(1) is bonded in a 9-coordinate geometry to one O(3), two equivalent O(1), two equivalent O(2), and four equivalent O(5) atoms. Dy(1) is bonded to four equivalent O(1) and eight equivalent O(4) atoms to form DyO12 cuboctahedra that share faces with two equivalent Dy(1)O12 cuboctahedra and faces with eight equivalent Nb(2)O6 octahedra. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(3) and four equivalent O(5) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 0-31°. In the second Nb site, Nb(2) is bonded to one O(2), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with five equivalent Nb(2)O6 octahedra, and faces with two equivalent Dy(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 12-37°. There are five inequivalent O sites. In the first O site, O(5) is bonded in a distorted bent 150 degrees geometry to two equivalent K(1), one Nb(1), and one Nb(2) atom. In the second O site, O(1) is bonded in a 2-coordinate geometry to one K(1), one Dy(1), and two equivalent Nb(2) atoms. In the third O site, O(2) is bonded in a 4-coordinate geometry to two equivalent K(1) and two equivalent Nb(2) atoms. In the fourth O site, O(3) is bonded in a linear geometry to two equivalent K(1) and two equivalent Nb(1) atoms. In the fifth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Dy(1) and two equivalent Nb(2) atoms. is represented by the CIF file [CIF]
data_K2DyNb5O15
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.751
_cell_length_b   12.751
_cell_length_c   3.954
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   642.843
_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  0.670  0.170  0.500  1.0
  K  K1  1  0.330  0.830  0.500  1.0
  K  K2  1  0.170  0.330  0.500  1.0
  K  K3  1  0.830  0.670  0.500  1.0
  Dy  Dy4  1  0.000  0.000  0.500  1.0
  Dy  Dy5  1  0.500  0.500  0.500  1.0
  Nb  Nb6  1  0.500  0.000  0.000  1.0
  Nb  Nb7  1  0.000  0.500  0.000  1.0
  Nb  Nb8  1  0.212  0.077  0.000  1.0
  Nb  Nb9  1  0.788  0.923  0.000  1.0
  Nb  Nb10  1  0.077  0.788  0.000  1.0
  Nb  Nb11  1  0.712  0.423  0.000  1.0
  Nb  Nb12  1  0.923  0.212  0.000  1.0
  Nb  Nb13  1  0.288  0.577  0.000  1.0
  Nb  Nb14  1  0.577  0.712  0.000  1.0
  Nb  Nb15  1  0.423  0.288  0.000  1.0
  O  O16  1  0.185  0.078  0.500  1.0
  O  O17  1  0.815  0.922  0.500  1.0
  O  O18  1  0.078  0.815  0.500  1.0
  O  O19  1  0.685  0.422  0.500  1.0
  O  O20  1  0.922  0.185  0.500  1.0
  O  O21  1  0.315  0.578  0.500  1.0
  O  O22  1  0.578  0.685  0.500  1.0
  O  O23  1  0.422  0.315  0.500  1.0
  O  O24  1  0.217  0.717  0.000  1.0
  O  O25  1  0.783  0.283  0.000  1.0
  O  O26  1  0.717  0.783  0.000  1.0
  O  O27  1  0.283  0.217  0.000  1.0
  O  O28  1  0.500  0.000  0.500  1.0
  O  O29  1  0.000  0.500  0.500  1.0
  O  O30  1  0.058  0.131  0.000  1.0
  O  O31  1  0.942  0.869  0.000  1.0
  O  O32  1  0.131  0.942  0.000  1.0
  O  O33  1  0.558  0.369  0.000  1.0
  O  O34  1  0.869  0.058  0.000  1.0
  O  O35  1  0.442  0.631  0.000  1.0
  O  O36  1  0.631  0.558  0.000  1.0
  O  O37  1  0.369  0.442  0.000  1.0
  O  O38  1  0.342  1.000  0.000  1.0
  O  O39  1  0.658  0.000  0.000  1.0
  O  O40  1  1.000  0.658  0.000  1.0
  O  O41  1  0.842  0.500  0.000  1.0
  O  O42  1  0.000  0.342  0.000  1.0
  O  O43  1  0.158  0.500  0.000  1.0
  O  O44  1  0.500  0.842  0.000  1.0
  O  O45  1  0.500  0.158  0.000  1.0
[/CIF]
.