The crystal structure described by K2Na2Gd4Nb2O13 crystallizes in the monoclinic C2/c space group. K(1) is bonded in a 10-coordinate geometry to two equivalent O(4), two equivalent O(6), two equivalent O(7), and four equivalent O(2) atoms. Na(1) is bonded to one O(2), one O(4), one O(5), one O(6), and one O(7) atom to form distorted NaO5 trigonal bipyramids that share corners with five equivalent Nb(1)O5 trigonal bipyramids and edges with two equivalent Gd(1)O7 pentagonal bipyramids. There are two inequivalent Gd sites. In the first Gd site, Gd(1) is bonded to one O(1), one O(4), one O(5), one O(6), one O(7), and two equivalent O(3) atoms to form distorted GdO7 pentagonal bipyramids that share  a cornercorner with one Gd(1)O7 pentagonal bipyramid,  an edgeedge with one Gd(1)O7 pentagonal bipyramid, edges with two equivalent Na(1)O5 trigonal bipyramids, and edges with two equivalent Nb(1)O5 trigonal bipyramids. In the second Gd site, Gd(2) is bonded in a 7-coordinate geometry to one O(1), one O(4), one O(5), one O(6), one O(7), and two equivalent O(3) atoms. Nb(1) is bonded to one O(2), one O(4), one O(5), one O(6), and one O(7) atom to form NbO5 trigonal bipyramids that share corners with five equivalent Na(1)O5 trigonal bipyramids and edges with two equivalent Gd(1)O7 pentagonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Gd(1) and two equivalent Gd(2) atoms to form OGd4 tetrahedra that share corners with four equivalent O(3)Gd4 tetrahedra, corners with four equivalent O(5)NaGd2Nb tetrahedra, and edges with two equivalent O(3)Gd4 tetrahedra. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent K(1), one Na(1), and one Nb(1) atom. In the third O site, O(3) is bonded to two equivalent Gd(1) and two equivalent Gd(2) atoms to form OGd4 tetrahedra that share corners with two equivalent O(1)Gd4 tetrahedra, corners with four equivalent O(5)NaGd2Nb tetrahedra,  an edgeedge with one O(1)Gd4 tetrahedra, and edges with two equivalent O(3)Gd4 tetrahedra. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to two equivalent K(1), one Na(1), one Gd(1), one Gd(2), and one Nb(1) atom. In the fifth O site, O(5) is bonded to one Na(1), one Gd(1), one Gd(2), and one Nb(1) atom to form corner-sharing ONaGd2Nb tetrahedra. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent K(1), one Na(1), one Gd(1), one Gd(2), and one Nb(1) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to two equivalent K(1), one Na(1), one Gd(1), one Gd(2), and one Nb(1) atom. is represented by the CIF file [CIF]
data_K2Na2Gd4Nb2O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.440
_cell_length_b   12.440
_cell_length_c   11.254
_cell_angle_alpha   64.408
_cell_angle_beta   64.408
_cell_angle_gamma   26.404
_symmetry_Int_Tables_number   1
_cell_volume   694.115
_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  0.196  0.306  0.633  1.0
  K  K1  1  0.804  0.694  0.367  1.0
  K  K2  1  0.694  0.804  0.867  1.0
  K  K3  1  0.306  0.196  0.133  1.0
  Na  Na4  1  0.801  0.881  0.522  1.0
  Na  Na5  1  0.199  0.119  0.478  1.0
  Na  Na6  1  0.881  0.801  0.022  1.0
  Na  Na7  1  0.119  0.199  0.978  1.0
  Gd  Gd8  1  0.391  0.484  0.450  1.0
  Gd  Gd9  1  0.484  0.391  0.950  1.0
  Gd  Gd10  1  0.099  0.026  0.328  1.0
  Gd  Gd11  1  0.609  0.516  0.550  1.0
  Gd  Gd12  1  0.516  0.609  0.050  1.0
  Gd  Gd13  1  0.974  0.901  0.172  1.0
  Gd  Gd14  1  0.026  0.099  0.828  1.0
  Gd  Gd15  1  0.901  0.974  0.672  1.0
  Nb  Nb16  1  0.616  0.685  0.718  1.0
  Nb  Nb17  1  0.384  0.315  0.282  1.0
  Nb  Nb18  1  0.685  0.616  0.218  1.0
  Nb  Nb19  1  0.315  0.384  0.782  1.0
  O  O20  1  0.246  0.754  0.250  1.0
  O  O21  1  0.669  0.802  0.622  1.0
  O  O22  1  0.751  0.246  0.477  1.0
  O  O23  1  0.135  0.595  0.377  1.0
  O  O24  1  0.405  0.865  0.123  1.0
  O  O25  1  0.331  0.198  0.378  1.0
  O  O26  1  0.754  0.246  0.750  1.0
  O  O27  1  0.198  0.331  0.878  1.0
  O  O28  1  0.829  0.369  0.161  1.0
  O  O29  1  0.092  0.645  0.639  1.0
  O  O30  1  0.754  0.249  0.023  1.0
  O  O31  1  0.645  0.092  0.139  1.0
  O  O32  1  0.369  0.829  0.661  1.0
  O  O33  1  0.355  0.908  0.861  1.0
  O  O34  1  0.865  0.405  0.623  1.0
  O  O35  1  0.561  0.180  0.636  1.0
  O  O36  1  0.249  0.754  0.523  1.0
  O  O37  1  0.595  0.135  0.877  1.0
  O  O38  1  0.631  0.171  0.339  1.0
  O  O39  1  0.180  0.561  0.136  1.0
  O  O40  1  0.171  0.631  0.839  1.0
  O  O41  1  0.908  0.355  0.361  1.0
  O  O42  1  0.802  0.669  0.122  1.0
  O  O43  1  0.246  0.751  0.977  1.0
  O  O44  1  0.439  0.820  0.364  1.0
  O  O45  1  0.820  0.439  0.864  1.0
[/CIF]
.
The crystal structure described by K2Na2Gd4Nb2O13 crystallizes in the monoclinic C2/c space group. K(1) is bonded in a 10-coordinate geometry to two equivalent O(4), two equivalent O(6), two equivalent O(7), and four equivalent O(2) atoms. Na(1) is bonded to one O(2), one O(4), one O(5), one O(6), and one O(7) atom to form distorted NaO5 trigonal bipyramids that share corners with five equivalent Nb(1)O5 trigonal bipyramids and edges with two equivalent Gd(1)O7 pentagonal bipyramids. There are two inequivalent Gd sites. In the first Gd site, Gd(1) is bonded to one O(1), one O(4), one O(5), one O(6), one O(7), and two equivalent O(3) atoms to form distorted GdO7 pentagonal bipyramids that share  a cornercorner with one Gd(1)O7 pentagonal bipyramid,  an edgeedge with one Gd(1)O7 pentagonal bipyramid, edges with two equivalent Na(1)O5 trigonal bipyramids, and edges with two equivalent Nb(1)O5 trigonal bipyramids. In the second Gd site, Gd(2) is bonded in a 7-coordinate geometry to one O(1), one O(4), one O(5), one O(6), one O(7), and two equivalent O(3) atoms. Nb(1) is bonded to one O(2), one O(4), one O(5), one O(6), and one O(7) atom to form NbO5 trigonal bipyramids that share corners with five equivalent Na(1)O5 trigonal bipyramids and edges with two equivalent Gd(1)O7 pentagonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Gd(1) and two equivalent Gd(2) atoms to form OGd4 tetrahedra that share corners with four equivalent O(3)Gd4 tetrahedra, corners with four equivalent O(5)NaGd2Nb tetrahedra, and edges with two equivalent O(3)Gd4 tetrahedra. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent K(1), one Na(1), and one Nb(1) atom. In the third O site, O(3) is bonded to two equivalent Gd(1) and two equivalent Gd(2) atoms to form OGd4 tetrahedra that share corners with two equivalent O(1)Gd4 tetrahedra, corners with four equivalent O(5)NaGd2Nb tetrahedra,  an edgeedge with one O(1)Gd4 tetrahedra, and edges with two equivalent O(3)Gd4 tetrahedra. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to two equivalent K(1), one Na(1), one Gd(1), one Gd(2), and one Nb(1) atom. In the fifth O site, O(5) is bonded to one Na(1), one Gd(1), one Gd(2), and one Nb(1) atom to form corner-sharing ONaGd2Nb tetrahedra. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent K(1), one Na(1), one Gd(1), one Gd(2), and one Nb(1) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to two equivalent K(1), one Na(1), one Gd(1), one Gd(2), and one Nb(1) atom. is represented by the CIF file [CIF]
data_K2Na2Gd4Nb2O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.440
_cell_length_b   12.440
_cell_length_c   11.254
_cell_angle_alpha   64.408
_cell_angle_beta   64.408
_cell_angle_gamma   26.404
_symmetry_Int_Tables_number   1
_cell_volume   694.115
_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  0.196  0.306  0.633  1.0
  K  K1  1  0.804  0.694  0.367  1.0
  K  K2  1  0.694  0.804  0.867  1.0
  K  K3  1  0.306  0.196  0.133  1.0
  Na  Na4  1  0.801  0.881  0.522  1.0
  Na  Na5  1  0.199  0.119  0.478  1.0
  Na  Na6  1  0.881  0.801  0.022  1.0
  Na  Na7  1  0.119  0.199  0.978  1.0
  Gd  Gd8  1  0.391  0.484  0.450  1.0
  Gd  Gd9  1  0.484  0.391  0.950  1.0
  Gd  Gd10  1  0.099  0.026  0.328  1.0
  Gd  Gd11  1  0.609  0.516  0.550  1.0
  Gd  Gd12  1  0.516  0.609  0.050  1.0
  Gd  Gd13  1  0.974  0.901  0.172  1.0
  Gd  Gd14  1  0.026  0.099  0.828  1.0
  Gd  Gd15  1  0.901  0.974  0.672  1.0
  Nb  Nb16  1  0.616  0.685  0.718  1.0
  Nb  Nb17  1  0.384  0.315  0.282  1.0
  Nb  Nb18  1  0.685  0.616  0.218  1.0
  Nb  Nb19  1  0.315  0.384  0.782  1.0
  O  O20  1  0.246  0.754  0.250  1.0
  O  O21  1  0.669  0.802  0.622  1.0
  O  O22  1  0.751  0.246  0.477  1.0
  O  O23  1  0.135  0.595  0.377  1.0
  O  O24  1  0.405  0.865  0.123  1.0
  O  O25  1  0.331  0.198  0.378  1.0
  O  O26  1  0.754  0.246  0.750  1.0
  O  O27  1  0.198  0.331  0.878  1.0
  O  O28  1  0.829  0.369  0.161  1.0
  O  O29  1  0.092  0.645  0.639  1.0
  O  O30  1  0.754  0.249  0.023  1.0
  O  O31  1  0.645  0.092  0.139  1.0
  O  O32  1  0.369  0.829  0.661  1.0
  O  O33  1  0.355  0.908  0.861  1.0
  O  O34  1  0.865  0.405  0.623  1.0
  O  O35  1  0.561  0.180  0.636  1.0
  O  O36  1  0.249  0.754  0.523  1.0
  O  O37  1  0.595  0.135  0.877  1.0
  O  O38  1  0.631  0.171  0.339  1.0
  O  O39  1  0.180  0.561  0.136  1.0
  O  O40  1  0.171  0.631  0.839  1.0
  O  O41  1  0.908  0.355  0.361  1.0
  O  O42  1  0.802  0.669  0.122  1.0
  O  O43  1  0.246  0.751  0.977  1.0
  O  O44  1  0.439  0.820  0.364  1.0
  O  O45  1  0.820  0.439  0.864  1.0
[/CIF]
.