The crystal structure described by Na2Sr2Nb4O13 crystallizes in the orthorhombic Imm2 space group. Na(1) is bonded to one O(2), one O(5), one O(7), two equivalent O(3), and two equivalent O(6) atoms to form distorted NaO7 hexagonal pyramids that share  a cornercorner with one Na(1)O7 hexagonal pyramid, corners with two equivalent Sr(1)O7 hexagonal pyramids,  an edgeedge with one Na(1)O7 hexagonal pyramid, edges with two equivalent Sr(1)O7 hexagonal pyramids, edges with two equivalent Nb(1)O6 octahedra, and edges with four equivalent Nb(2)O6 octahedra. Sr(1) is bonded to one O(1), one O(4), one O(7), two equivalent O(3), and two equivalent O(6) atoms to form distorted SrO7 hexagonal pyramids that share  a cornercorner with one Sr(1)O7 hexagonal pyramid, corners with two equivalent Na(1)O7 hexagonal pyramids,  an edgeedge with one Sr(1)O7 hexagonal pyramid, edges with two equivalent Na(1)O7 hexagonal pyramids, edges with two equivalent Nb(2)O6 octahedra, and edges with four equivalent Nb(1)O6 octahedra. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(4), two equivalent O(3), and two equivalent O(6) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with four equivalent Nb(2)O6 octahedra, edges with two equivalent Na(1)O7 hexagonal pyramids, and edges with four equivalent Sr(1)O7 hexagonal pyramids. The corner-sharing octahedral tilt angles range from 39-43°. In the second Nb site, Nb(2) is bonded to one O(2), one O(5), two equivalent O(3), and two equivalent O(6) atoms to form NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, edges with two equivalent Sr(1)O7 hexagonal pyramids, and edges with four equivalent Na(1)O7 hexagonal pyramids. The corner-sharing octahedral tilt angles range from 36-42°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sr(1) and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Na(1) and two equivalent Nb(2) atoms. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Sr(1), one Nb(1), and one Nb(2) atom. In the fourth O site, O(4) is bonded to two equivalent Sr(1) and two equivalent Nb(1) atoms to form distorted corner-sharing OSr2Nb2 tetrahedra. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(1) and two equivalent Nb(2) atoms. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(1), one Sr(1), one Nb(1), and one Nb(2) atom. In the seventh O site, O(7) is bonded to two equivalent Na(1) and two equivalent Sr(1) atoms to form corner-sharing ONa2Sr2 tetrahedra. is represented by the CIF file [CIF]
data_Na2Sr2Nb4O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.557
_cell_length_b   7.557
_cell_length_c   7.557
_cell_angle_alpha   120.135
_cell_angle_beta   119.698
_cell_angle_gamma   90.145
_symmetry_Int_Tables_number   1
_cell_volume   305.502
_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
  Na  Na0  1  0.758  0.988  0.230  1.0
  Na  Na1  1  0.758  0.528  0.770  1.0
  Sr  Sr2  1  0.752  0.991  0.761  1.0
  Sr  Sr3  1  0.230  0.991  0.239  1.0
  Nb  Nb4  1  0.250  0.499  0.249  1.0
  Nb  Nb5  1  0.250  0.001  0.751  1.0
  Nb  Nb6  1  0.250  0.501  0.750  1.0
  Nb  Nb7  1  0.751  0.501  0.250  1.0
  O  O8  1  0.183  0.183  0.000  1.0
  O  O9  1  0.559  0.559  0.000  1.0
  O  O10  1  0.190  0.565  0.004  1.0
  O  O11  1  0.561  0.186  0.996  1.0
  O  O12  1  0.190  0.186  0.625  1.0
  O  O13  1  0.561  0.565  0.375  1.0
  O  O14  1  0.320  0.820  0.500  1.0
  O  O15  1  0.935  0.435  0.500  1.0
  O  O16  1  0.316  0.429  0.497  1.0
  O  O17  1  0.932  0.819  0.503  1.0
  O  O18  1  0.316  0.819  0.887  1.0
  O  O19  1  0.932  0.429  0.113  1.0
  O  O20  1  0.878  0.878  0.000  1.0
[/CIF]
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The crystal structure described by Na2Sr2Nb4O13 crystallizes in the orthorhombic Imm2 space group. Na(1) is bonded to one O(2), one O(5), one O(7), two equivalent O(3), and two equivalent O(6) atoms to form distorted NaO7 hexagonal pyramids that share  a cornercorner with one Na(1)O7 hexagonal pyramid, corners with two equivalent Sr(1)O7 hexagonal pyramids,  an edgeedge with one Na(1)O7 hexagonal pyramid, edges with two equivalent Sr(1)O7 hexagonal pyramids, edges with two equivalent Nb(1)O6 octahedra, and edges with four equivalent Nb(2)O6 octahedra. Sr(1) is bonded to one O(1), one O(4), one O(7), two equivalent O(3), and two equivalent O(6) atoms to form distorted SrO7 hexagonal pyramids that share  a cornercorner with one Sr(1)O7 hexagonal pyramid, corners with two equivalent Na(1)O7 hexagonal pyramids,  an edgeedge with one Sr(1)O7 hexagonal pyramid, edges with two equivalent Na(1)O7 hexagonal pyramids, edges with two equivalent Nb(2)O6 octahedra, and edges with four equivalent Nb(1)O6 octahedra. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(4), two equivalent O(3), and two equivalent O(6) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with four equivalent Nb(2)O6 octahedra, edges with two equivalent Na(1)O7 hexagonal pyramids, and edges with four equivalent Sr(1)O7 hexagonal pyramids. The corner-sharing octahedral tilt angles range from 39-43°. In the second Nb site, Nb(2) is bonded to one O(2), one O(5), two equivalent O(3), and two equivalent O(6) atoms to form NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, edges with two equivalent Sr(1)O7 hexagonal pyramids, and edges with four equivalent Na(1)O7 hexagonal pyramids. The corner-sharing octahedral tilt angles range from 36-42°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sr(1) and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Na(1) and two equivalent Nb(2) atoms. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Sr(1), one Nb(1), and one Nb(2) atom. In the fourth O site, O(4) is bonded to two equivalent Sr(1) and two equivalent Nb(1) atoms to form distorted corner-sharing OSr2Nb2 tetrahedra. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(1) and two equivalent Nb(2) atoms. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(1), one Sr(1), one Nb(1), and one Nb(2) atom. In the seventh O site, O(7) is bonded to two equivalent Na(1) and two equivalent Sr(1) atoms to form corner-sharing ONa2Sr2 tetrahedra. is represented by the CIF file [CIF]
data_Na2Sr2Nb4O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.557
_cell_length_b   7.557
_cell_length_c   7.557
_cell_angle_alpha   120.135
_cell_angle_beta   119.698
_cell_angle_gamma   90.145
_symmetry_Int_Tables_number   1
_cell_volume   305.502
_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
  Na  Na0  1  0.758  0.988  0.230  1.0
  Na  Na1  1  0.758  0.528  0.770  1.0
  Sr  Sr2  1  0.752  0.991  0.761  1.0
  Sr  Sr3  1  0.230  0.991  0.239  1.0
  Nb  Nb4  1  0.250  0.499  0.249  1.0
  Nb  Nb5  1  0.250  0.001  0.751  1.0
  Nb  Nb6  1  0.250  0.501  0.750  1.0
  Nb  Nb7  1  0.751  0.501  0.250  1.0
  O  O8  1  0.183  0.183  0.000  1.0
  O  O9  1  0.559  0.559  0.000  1.0
  O  O10  1  0.190  0.565  0.004  1.0
  O  O11  1  0.561  0.186  0.996  1.0
  O  O12  1  0.190  0.186  0.625  1.0
  O  O13  1  0.561  0.565  0.375  1.0
  O  O14  1  0.320  0.820  0.500  1.0
  O  O15  1  0.935  0.435  0.500  1.0
  O  O16  1  0.316  0.429  0.497  1.0
  O  O17  1  0.932  0.819  0.503  1.0
  O  O18  1  0.316  0.819  0.887  1.0
  O  O19  1  0.932  0.429  0.113  1.0
  O  O20  1  0.878  0.878  0.000  1.0
[/CIF]
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