The material structure described by K2Na2Eu4Nb2O13 crystallizes in the monoclinic C2/c space group. K(1) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and four equivalent O(4) atoms. Na(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(6) atom to form distorted NaO5 trigonal bipyramids that share corners with five equivalent Nb(1)O5 trigonal bipyramids and edges with two equivalent Eu(1)O7 pentagonal bipyramids. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and two equivalent O(7) atoms to form distorted EuO7 pentagonal bipyramids that share  a cornercorner with one Eu(1)O7 pentagonal bipyramid,  an edgeedge with one Eu(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 Eu site, Eu(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(5), one O(6), and two equivalent O(7) atoms. Nb(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(6) atom to form NbO5 trigonal bipyramids that share corners with five equivalent Na(1)O5 trigonal bipyramids and edges with two equivalent Eu(1)O7 pentagonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent K(1), one Na(1), one Eu(1), one Eu(2), and one Nb(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent K(1), one Na(1), one Eu(1), one Eu(2), and one Nb(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent K(1), one Na(1), one Eu(1), one Eu(2), and one Nb(1) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to four equivalent K(1), one Na(1), and one Nb(1) atom. In the fifth O site, O(5) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form OEu4 tetrahedra that share corners with four equivalent O(7)Eu4 tetrahedra, corners with four equivalent O(6)NaEu2Nb tetrahedra, and edges with two equivalent O(7)Eu4 tetrahedra. In the sixth O site, O(6) is bonded to one Na(1), one Eu(1), one Eu(2), and one Nb(1) atom to form corner-sharing ONaEu2Nb tetrahedra. In the seventh O site, O(7) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form OEu4 tetrahedra that share corners with two equivalent O(5)Eu4 tetrahedra, corners with four equivalent O(6)NaEu2Nb tetrahedra,  an edgeedge with one O(5)Eu4 tetrahedra, and edges with two equivalent O(7)Eu4 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2Na2Eu4Nb2O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.596
_cell_length_b   12.596
_cell_length_c   11.385
_cell_angle_alpha   64.273
_cell_angle_beta   64.273
_cell_angle_gamma   26.366
_symmetry_Int_Tables_number   1
_cell_volume   718.076
_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  0.802  0.697  0.367  1.0
  K  K1  1  0.303  0.198  0.133  1.0
  K  K2  1  0.198  0.303  0.633  1.0
  K  K3  1  0.697  0.802  0.867  1.0
  Na  Na4  1  0.880  0.803  0.023  1.0
  Na  Na5  1  0.197  0.120  0.477  1.0
  Na  Na6  1  0.120  0.197  0.977  1.0
  Na  Na7  1  0.803  0.880  0.523  1.0
  Eu  Eu8  1  0.605  0.521  0.552  1.0
  Eu  Eu9  1  0.479  0.395  0.948  1.0
  Eu  Eu10  1  0.395  0.479  0.448  1.0
  Eu  Eu11  1  0.521  0.605  0.052  1.0
  Eu  Eu12  1  0.971  0.904  0.174  1.0
  Eu  Eu13  1  0.096  0.029  0.326  1.0
  Eu  Eu14  1  0.029  0.096  0.826  1.0
  Eu  Eu15  1  0.904  0.971  0.674  1.0
  Nb  Nb16  1  0.685  0.616  0.218  1.0
  Nb  Nb17  1  0.384  0.315  0.282  1.0
  Nb  Nb18  1  0.315  0.384  0.782  1.0
  Nb  Nb19  1  0.616  0.685  0.718  1.0
  O  O20  1  0.909  0.354  0.359  1.0
  O  O21  1  0.646  0.091  0.141  1.0
  O  O22  1  0.091  0.646  0.641  1.0
  O  O23  1  0.354  0.909  0.859  1.0
  O  O24  1  0.860  0.407  0.624  1.0
  O  O25  1  0.593  0.140  0.876  1.0
  O  O26  1  0.140  0.593  0.376  1.0
  O  O27  1  0.407  0.860  0.124  1.0
  O  O28  1  0.181  0.559  0.137  1.0
  O  O29  1  0.441  0.819  0.363  1.0
  O  O30  1  0.819  0.441  0.863  1.0
  O  O31  1  0.559  0.181  0.637  1.0
  O  O32  1  0.799  0.672  0.124  1.0
  O  O33  1  0.328  0.201  0.376  1.0
  O  O34  1  0.201  0.328  0.876  1.0
  O  O35  1  0.672  0.799  0.624  1.0
  O  O36  1  0.241  0.759  0.250  1.0
  O  O37  1  0.759  0.241  0.750  1.0
  O  O38  1  0.370  0.832  0.659  1.0
  O  O39  1  0.168  0.630  0.841  1.0
  O  O40  1  0.630  0.168  0.341  1.0
  O  O41  1  0.832  0.370  0.159  1.0
  O  O42  1  0.751  0.247  0.479  1.0
  O  O43  1  0.753  0.249  0.021  1.0
  O  O44  1  0.249  0.753  0.521  1.0
  O  O45  1  0.247  0.751  0.979  1.0
[/CIF]
.
The material structure described by K2Na2Eu4Nb2O13 crystallizes in the monoclinic C2/c space group. K(1) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and four equivalent O(4) atoms. Na(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(6) atom to form distorted NaO5 trigonal bipyramids that share corners with five equivalent Nb(1)O5 trigonal bipyramids and edges with two equivalent Eu(1)O7 pentagonal bipyramids. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and two equivalent O(7) atoms to form distorted EuO7 pentagonal bipyramids that share  a cornercorner with one Eu(1)O7 pentagonal bipyramid,  an edgeedge with one Eu(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 Eu site, Eu(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(5), one O(6), and two equivalent O(7) atoms. Nb(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(6) atom to form NbO5 trigonal bipyramids that share corners with five equivalent Na(1)O5 trigonal bipyramids and edges with two equivalent Eu(1)O7 pentagonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent K(1), one Na(1), one Eu(1), one Eu(2), and one Nb(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent K(1), one Na(1), one Eu(1), one Eu(2), and one Nb(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent K(1), one Na(1), one Eu(1), one Eu(2), and one Nb(1) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to four equivalent K(1), one Na(1), and one Nb(1) atom. In the fifth O site, O(5) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form OEu4 tetrahedra that share corners with four equivalent O(7)Eu4 tetrahedra, corners with four equivalent O(6)NaEu2Nb tetrahedra, and edges with two equivalent O(7)Eu4 tetrahedra. In the sixth O site, O(6) is bonded to one Na(1), one Eu(1), one Eu(2), and one Nb(1) atom to form corner-sharing ONaEu2Nb tetrahedra. In the seventh O site, O(7) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form OEu4 tetrahedra that share corners with two equivalent O(5)Eu4 tetrahedra, corners with four equivalent O(6)NaEu2Nb tetrahedra,  an edgeedge with one O(5)Eu4 tetrahedra, and edges with two equivalent O(7)Eu4 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2Na2Eu4Nb2O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.596
_cell_length_b   12.596
_cell_length_c   11.385
_cell_angle_alpha   64.273
_cell_angle_beta   64.273
_cell_angle_gamma   26.366
_symmetry_Int_Tables_number   1
_cell_volume   718.076
_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  0.802  0.697  0.367  1.0
  K  K1  1  0.303  0.198  0.133  1.0
  K  K2  1  0.198  0.303  0.633  1.0
  K  K3  1  0.697  0.802  0.867  1.0
  Na  Na4  1  0.880  0.803  0.023  1.0
  Na  Na5  1  0.197  0.120  0.477  1.0
  Na  Na6  1  0.120  0.197  0.977  1.0
  Na  Na7  1  0.803  0.880  0.523  1.0
  Eu  Eu8  1  0.605  0.521  0.552  1.0
  Eu  Eu9  1  0.479  0.395  0.948  1.0
  Eu  Eu10  1  0.395  0.479  0.448  1.0
  Eu  Eu11  1  0.521  0.605  0.052  1.0
  Eu  Eu12  1  0.971  0.904  0.174  1.0
  Eu  Eu13  1  0.096  0.029  0.326  1.0
  Eu  Eu14  1  0.029  0.096  0.826  1.0
  Eu  Eu15  1  0.904  0.971  0.674  1.0
  Nb  Nb16  1  0.685  0.616  0.218  1.0
  Nb  Nb17  1  0.384  0.315  0.282  1.0
  Nb  Nb18  1  0.315  0.384  0.782  1.0
  Nb  Nb19  1  0.616  0.685  0.718  1.0
  O  O20  1  0.909  0.354  0.359  1.0
  O  O21  1  0.646  0.091  0.141  1.0
  O  O22  1  0.091  0.646  0.641  1.0
  O  O23  1  0.354  0.909  0.859  1.0
  O  O24  1  0.860  0.407  0.624  1.0
  O  O25  1  0.593  0.140  0.876  1.0
  O  O26  1  0.140  0.593  0.376  1.0
  O  O27  1  0.407  0.860  0.124  1.0
  O  O28  1  0.181  0.559  0.137  1.0
  O  O29  1  0.441  0.819  0.363  1.0
  O  O30  1  0.819  0.441  0.863  1.0
  O  O31  1  0.559  0.181  0.637  1.0
  O  O32  1  0.799  0.672  0.124  1.0
  O  O33  1  0.328  0.201  0.376  1.0
  O  O34  1  0.201  0.328  0.876  1.0
  O  O35  1  0.672  0.799  0.624  1.0
  O  O36  1  0.241  0.759  0.250  1.0
  O  O37  1  0.759  0.241  0.750  1.0
  O  O38  1  0.370  0.832  0.659  1.0
  O  O39  1  0.168  0.630  0.841  1.0
  O  O40  1  0.630  0.168  0.341  1.0
  O  O41  1  0.832  0.370  0.159  1.0
  O  O42  1  0.751  0.247  0.479  1.0
  O  O43  1  0.753  0.249  0.021  1.0
  O  O44  1  0.249  0.753  0.521  1.0
  O  O45  1  0.247  0.751  0.979  1.0
[/CIF]
.