The crystal structure described by K2Na2Sm4Nb2O13 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 Sm(1)O7 pentagonal bipyramids. There are two inequivalent Sm sites. In the first Sm site, Sm(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 SmO7 pentagonal bipyramids that share  a cornercorner with one Sm(1)O7 pentagonal bipyramid,  an edgeedge with one Sm(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 Sm site, Sm(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 Sm(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 Sm(1), one Sm(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 Sm(1), one Sm(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 Sm(1), one Sm(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 Sm(1) and two equivalent Sm(2) atoms to form OSm4 tetrahedra that share corners with four equivalent O(6)NaSm2Nb tetrahedra, corners with four equivalent O(7)Sm4 tetrahedra, and edges with two equivalent O(7)Sm4 tetrahedra. In the sixth O site, O(6) is bonded to one Na(1), one Sm(1), one Sm(2), and one Nb(1) atom to form corner-sharing ONaSm2Nb tetrahedra. In the seventh O site, O(7) is bonded to two equivalent Sm(1) and two equivalent Sm(2) atoms to form OSm4 tetrahedra that share corners with two equivalent O(5)Sm4 tetrahedra, corners with four equivalent O(6)NaSm2Nb tetrahedra,  an edgeedge with one O(5)Sm4 tetrahedra, and edges with two equivalent O(7)Sm4 tetrahedra. is represented by the CIF file [CIF]
data_K2Na2Sm4Nb2O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.555
_cell_length_b   12.555
_cell_length_c   11.333
_cell_angle_alpha   64.308
_cell_angle_beta   64.308
_cell_angle_gamma   26.357
_symmetry_Int_Tables_number   1
_cell_volume   710.103
_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  0.801  0.698  0.367  1.0
  K  K1  1  0.302  0.199  0.133  1.0
  K  K2  1  0.199  0.302  0.633  1.0
  K  K3  1  0.698  0.801  0.867  1.0
  Na  Na4  1  0.878  0.804  0.023  1.0
  Na  Na5  1  0.196  0.122  0.477  1.0
  Na  Na6  1  0.122  0.196  0.977  1.0
  Na  Na7  1  0.804  0.878  0.523  1.0
  Sm  Sm8  1  0.609  0.517  0.550  1.0
  Sm  Sm9  1  0.483  0.391  0.950  1.0
  Sm  Sm10  1  0.391  0.483  0.450  1.0
  Sm  Sm11  1  0.517  0.609  0.050  1.0
  Sm  Sm12  1  0.975  0.900  0.172  1.0
  Sm  Sm13  1  0.100  0.025  0.328  1.0
  Sm  Sm14  1  0.025  0.100  0.828  1.0
  Sm  Sm15  1  0.900  0.975  0.672  1.0
  Nb  Nb16  1  0.685  0.617  0.217  1.0
  Nb  Nb17  1  0.383  0.315  0.283  1.0
  Nb  Nb18  1  0.315  0.383  0.783  1.0
  Nb  Nb19  1  0.617  0.685  0.717  1.0
  O  O20  1  0.906  0.357  0.360  1.0
  O  O21  1  0.643  0.094  0.140  1.0
  O  O22  1  0.094  0.643  0.640  1.0
  O  O23  1  0.357  0.906  0.860  1.0
  O  O24  1  0.860  0.408  0.623  1.0
  O  O25  1  0.592  0.140  0.877  1.0
  O  O26  1  0.140  0.592  0.377  1.0
  O  O27  1  0.408  0.860  0.123  1.0
  O  O28  1  0.178  0.562  0.138  1.0
  O  O29  1  0.438  0.822  0.362  1.0
  O  O30  1  0.822  0.438  0.862  1.0
  O  O31  1  0.562  0.178  0.638  1.0
  O  O32  1  0.799  0.672  0.123  1.0
  O  O33  1  0.328  0.201  0.377  1.0
  O  O34  1  0.201  0.328  0.877  1.0
  O  O35  1  0.672  0.799  0.623  1.0
  O  O36  1  0.242  0.758  0.250  1.0
  O  O37  1  0.758  0.242  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  0.248  0.477  1.0
  O  O43  1  0.752  0.249  0.023  1.0
  O  O44  1  0.249  0.752  0.523  1.0
  O  O45  1  0.248  0.751  0.977  1.0
[/CIF]
.
The crystal structure described by K2Na2Sm4Nb2O13 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 Sm(1)O7 pentagonal bipyramids. There are two inequivalent Sm sites. In the first Sm site, Sm(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 SmO7 pentagonal bipyramids that share  a cornercorner with one Sm(1)O7 pentagonal bipyramid,  an edgeedge with one Sm(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 Sm site, Sm(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 Sm(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 Sm(1), one Sm(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 Sm(1), one Sm(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 Sm(1), one Sm(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 Sm(1) and two equivalent Sm(2) atoms to form OSm4 tetrahedra that share corners with four equivalent O(6)NaSm2Nb tetrahedra, corners with four equivalent O(7)Sm4 tetrahedra, and edges with two equivalent O(7)Sm4 tetrahedra. In the sixth O site, O(6) is bonded to one Na(1), one Sm(1), one Sm(2), and one Nb(1) atom to form corner-sharing ONaSm2Nb tetrahedra. In the seventh O site, O(7) is bonded to two equivalent Sm(1) and two equivalent Sm(2) atoms to form OSm4 tetrahedra that share corners with two equivalent O(5)Sm4 tetrahedra, corners with four equivalent O(6)NaSm2Nb tetrahedra,  an edgeedge with one O(5)Sm4 tetrahedra, and edges with two equivalent O(7)Sm4 tetrahedra. is represented by the CIF file [CIF]
data_K2Na2Sm4Nb2O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.555
_cell_length_b   12.555
_cell_length_c   11.333
_cell_angle_alpha   64.308
_cell_angle_beta   64.308
_cell_angle_gamma   26.357
_symmetry_Int_Tables_number   1
_cell_volume   710.103
_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  0.801  0.698  0.367  1.0
  K  K1  1  0.302  0.199  0.133  1.0
  K  K2  1  0.199  0.302  0.633  1.0
  K  K3  1  0.698  0.801  0.867  1.0
  Na  Na4  1  0.878  0.804  0.023  1.0
  Na  Na5  1  0.196  0.122  0.477  1.0
  Na  Na6  1  0.122  0.196  0.977  1.0
  Na  Na7  1  0.804  0.878  0.523  1.0
  Sm  Sm8  1  0.609  0.517  0.550  1.0
  Sm  Sm9  1  0.483  0.391  0.950  1.0
  Sm  Sm10  1  0.391  0.483  0.450  1.0
  Sm  Sm11  1  0.517  0.609  0.050  1.0
  Sm  Sm12  1  0.975  0.900  0.172  1.0
  Sm  Sm13  1  0.100  0.025  0.328  1.0
  Sm  Sm14  1  0.025  0.100  0.828  1.0
  Sm  Sm15  1  0.900  0.975  0.672  1.0
  Nb  Nb16  1  0.685  0.617  0.217  1.0
  Nb  Nb17  1  0.383  0.315  0.283  1.0
  Nb  Nb18  1  0.315  0.383  0.783  1.0
  Nb  Nb19  1  0.617  0.685  0.717  1.0
  O  O20  1  0.906  0.357  0.360  1.0
  O  O21  1  0.643  0.094  0.140  1.0
  O  O22  1  0.094  0.643  0.640  1.0
  O  O23  1  0.357  0.906  0.860  1.0
  O  O24  1  0.860  0.408  0.623  1.0
  O  O25  1  0.592  0.140  0.877  1.0
  O  O26  1  0.140  0.592  0.377  1.0
  O  O27  1  0.408  0.860  0.123  1.0
  O  O28  1  0.178  0.562  0.138  1.0
  O  O29  1  0.438  0.822  0.362  1.0
  O  O30  1  0.822  0.438  0.862  1.0
  O  O31  1  0.562  0.178  0.638  1.0
  O  O32  1  0.799  0.672  0.123  1.0
  O  O33  1  0.328  0.201  0.377  1.0
  O  O34  1  0.201  0.328  0.877  1.0
  O  O35  1  0.672  0.799  0.623  1.0
  O  O36  1  0.242  0.758  0.250  1.0
  O  O37  1  0.758  0.242  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  0.248  0.477  1.0
  O  O43  1  0.752  0.249  0.023  1.0
  O  O44  1  0.249  0.752  0.523  1.0
  O  O45  1  0.248  0.751  0.977  1.0
[/CIF]
.