The material structure described by Na5H7(Se2O9)2 crystallizes in the triclinic P1 space group. There are five inequivalent Na sites. In the first Na site, Na(1) is bonded in a 7-coordinate geometry to one O(1), one O(11), one O(14), one O(17), one O(6), one O(8), and one O(9) atom. In the second Na site, Na(2) is bonded to one O(10), one O(12), one O(13), one O(18), one O(2), one O(5), and one O(7) atom to form distorted NaO7 pentagonal bipyramids that share  a cornercorner with one Se(2)O4 tetrahedra,  a cornercorner with one Se(4)O4 tetrahedra, corners with two equivalent Se(1)O4 tetrahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Na(4)O6 octahedra,  an edgeedge with one Na(5)O6 octahedra, and  an edgeedge with one Se(4)O4 tetrahedra. In the third Na site, Na(3) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form distorted NaO6 octahedra that share corners with two equivalent Se(1)O4 tetrahedra, corners with two equivalent Se(2)O4 tetrahedra,  an edgeedge with one Na(4)O6 octahedra,  an edgeedge with one Na(5)O6 octahedra, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. In the fourth Na site, Na(4) is bonded to one O(10), one O(12), one O(15), one O(4), one O(8), and one O(9) atom to form NaO6 octahedra that share corners with two equivalent Se(2)O4 tetrahedra, corners with two equivalent Se(3)O4 tetrahedra, corners with two equivalent Se(4)O4 tetrahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Na(5)O6 octahedra, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. In the fifth Na site, Na(5) is bonded to one O(10), one O(11), one O(16), one O(3), one O(7), and one O(9) atom to form NaO6 octahedra that share corners with two equivalent Se(1)O4 tetrahedra, corners with two equivalent Se(3)O4 tetrahedra, corners with two equivalent Se(4)O4 tetrahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Na(4)O6 octahedra, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. There are seven inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(5) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(6) atom. In the third H site, H(3) is bonded in a single-bond geometry to one O(5) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(6) atom. In the fifth H site, H(5) is bonded in a distorted linear geometry to one O(13) and one O(15) atom. In the sixth H site, H(6) is bonded in a distorted linear geometry to one O(14) and one O(16) atom. In the seventh H site, H(7) is bonded in a linear geometry to one O(11) and one O(12) atom. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to one O(1), one O(13), one O(3), and one O(7) atom to form SeO4 tetrahedra that share corners with two equivalent Na(3)O6 octahedra, corners with two equivalent Na(5)O6 octahedra, and corners with two equivalent Na(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 42-75°. In the second Se site, Se(2) is bonded to one O(14), one O(2), one O(4), and one O(8) atom to form SeO4 tetrahedra that share corners with two equivalent Na(3)O6 octahedra, corners with two equivalent Na(4)O6 octahedra, and  a cornercorner with one Na(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 42-75°. In the third Se site, Se(3) is bonded to one O(11), one O(15), one O(17), and one O(9) atom to form SeO4 tetrahedra that share corners with two equivalent Na(4)O6 octahedra and corners with two equivalent Na(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-61°. In the fourth Se site, Se(4) is bonded to one O(10), one O(12), one O(16), and one O(18) atom to form SeO4 tetrahedra that share corners with two equivalent Na(4)O6 octahedra, corners with two equivalent Na(5)O6 octahedra,  a cornercorner with one Na(2)O7 pentagonal bipyramid, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 41-59°. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Na(1) and one Se(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Na(2) and one Se(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(3), one Na(5), and one Se(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(3), one Na(4), and one Se(2) atom. In the fifth O site, O(5) is bonded in a distorted water-like geometry to one Na(2), one Na(3), one H(1), and one H(3) atom. In the sixth O site, O(6) is bonded in a distorted water-like geometry to one Na(1), one Na(3), one H(2), and one H(4) atom. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), one Na(3), one Na(5), and one Se(1) atom. In the eighth O site, O(8) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(3), one Na(4), and one Se(2) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Na(5), and one Se(3) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Na(2), one Na(4), one Na(5), and one Se(4) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Na(1), one Na(5), one H(7), and one Se(3) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Na(2), one Na(4), one H(7), and one Se(4) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Na(2), one H(5), and one Se(1) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Na(1), one H(6), and one Se(2) atom. In the fifteenth O site, O(15) is bonded in a distorted trigonal planar geometry to one Na(4), one H(5), and one Se(3) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal planar geometry to one Na(5), one H(6), and one Se(4) atom. In the seventeenth O site, O(17) is bonded in a water-like geometry to one Na(1) and one Se(3) atom. In the eighteenth O site, O(18) is bonded in a distorted water-like geometry to one Na(2) and one Se(4) atom. is represented by the CIF card [CIF]
data_Na5H7(Se2O9)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.070
_cell_length_b   7.467
_cell_length_c   10.040
_cell_angle_alpha   102.683
_cell_angle_beta   99.197
_cell_angle_gamma   100.015
_symmetry_Int_Tables_number   1
_cell_volume   427.824
_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  0.655  0.741  0.190  1.0
  Na  Na1  1  0.346  0.258  0.807  1.0
  Na  Na2  1  0.000  0.001  1.000  1.0
  Na  Na3  1  0.136  0.176  0.400  1.0
  Na  Na4  1  0.869  0.823  0.605  1.0
  H  H5  1  0.953  0.324  0.917  1.0
  H  H6  1  0.050  0.678  0.080  1.0
  H  H7  1  0.146  0.388  0.054  1.0
  H  H8  1  0.854  0.609  0.944  1.0
  H  H9  1  0.288  0.561  0.621  1.0
  H  H10  1  0.713  0.438  0.382  1.0
  H  H11  1  0.500  0.985  0.498  1.0
  Se  Se12  1  0.414  0.799  0.826  1.0
  Se  Se13  1  0.586  0.202  0.176  1.0
  Se  Se14  1  0.249  0.693  0.374  1.0
  Se  Se15  1  0.748  0.306  0.627  1.0
  O  O16  1  0.414  0.773  0.984  1.0
  O  O17  1  0.586  0.228  0.018  1.0
  O  O18  1  0.669  0.875  0.795  1.0
  O  O19  1  0.331  0.126  0.207  1.0
  O  O20  1  0.094  0.296  0.964  1.0
  O  O21  1  0.906  0.703  0.034  1.0
  O  O22  1  0.220  0.915  0.774  1.0
  O  O23  1  0.780  0.084  0.227  1.0
  O  O24  1  0.056  0.823  0.400  1.0
  O  O25  1  0.946  0.179  0.602  1.0
  O  O26  1  0.517  0.840  0.448  1.0
  O  O27  1  0.485  0.160  0.558  1.0
  O  O28  1  0.313  0.563  0.724  1.0
  O  O29  1  0.688  0.437  0.278  1.0
  O  O30  1  0.232  0.520  0.454  1.0
  O  O31  1  0.769  0.480  0.547  1.0
  O  O32  1  0.260  0.617  0.208  1.0
  O  O33  1  0.749  0.389  0.796  1.0
[/CIF]
.
The material structure described by Na5H7(Se2O9)2 crystallizes in the triclinic P1 space group. There are five inequivalent Na sites. In the first Na site, Na(1) is bonded in a 7-coordinate geometry to one O(1), one O(11), one O(14), one O(17), one O(6), one O(8), and one O(9) atom. In the second Na site, Na(2) is bonded to one O(10), one O(12), one O(13), one O(18), one O(2), one O(5), and one O(7) atom to form distorted NaO7 pentagonal bipyramids that share  a cornercorner with one Se(2)O4 tetrahedra,  a cornercorner with one Se(4)O4 tetrahedra, corners with two equivalent Se(1)O4 tetrahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Na(4)O6 octahedra,  an edgeedge with one Na(5)O6 octahedra, and  an edgeedge with one Se(4)O4 tetrahedra. In the third Na site, Na(3) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form distorted NaO6 octahedra that share corners with two equivalent Se(1)O4 tetrahedra, corners with two equivalent Se(2)O4 tetrahedra,  an edgeedge with one Na(4)O6 octahedra,  an edgeedge with one Na(5)O6 octahedra, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. In the fourth Na site, Na(4) is bonded to one O(10), one O(12), one O(15), one O(4), one O(8), and one O(9) atom to form NaO6 octahedra that share corners with two equivalent Se(2)O4 tetrahedra, corners with two equivalent Se(3)O4 tetrahedra, corners with two equivalent Se(4)O4 tetrahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Na(5)O6 octahedra, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. In the fifth Na site, Na(5) is bonded to one O(10), one O(11), one O(16), one O(3), one O(7), and one O(9) atom to form NaO6 octahedra that share corners with two equivalent Se(1)O4 tetrahedra, corners with two equivalent Se(3)O4 tetrahedra, corners with two equivalent Se(4)O4 tetrahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Na(4)O6 octahedra, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. There are seven inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(5) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(6) atom. In the third H site, H(3) is bonded in a single-bond geometry to one O(5) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(6) atom. In the fifth H site, H(5) is bonded in a distorted linear geometry to one O(13) and one O(15) atom. In the sixth H site, H(6) is bonded in a distorted linear geometry to one O(14) and one O(16) atom. In the seventh H site, H(7) is bonded in a linear geometry to one O(11) and one O(12) atom. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to one O(1), one O(13), one O(3), and one O(7) atom to form SeO4 tetrahedra that share corners with two equivalent Na(3)O6 octahedra, corners with two equivalent Na(5)O6 octahedra, and corners with two equivalent Na(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 42-75°. In the second Se site, Se(2) is bonded to one O(14), one O(2), one O(4), and one O(8) atom to form SeO4 tetrahedra that share corners with two equivalent Na(3)O6 octahedra, corners with two equivalent Na(4)O6 octahedra, and  a cornercorner with one Na(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 42-75°. In the third Se site, Se(3) is bonded to one O(11), one O(15), one O(17), and one O(9) atom to form SeO4 tetrahedra that share corners with two equivalent Na(4)O6 octahedra and corners with two equivalent Na(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-61°. In the fourth Se site, Se(4) is bonded to one O(10), one O(12), one O(16), and one O(18) atom to form SeO4 tetrahedra that share corners with two equivalent Na(4)O6 octahedra, corners with two equivalent Na(5)O6 octahedra,  a cornercorner with one Na(2)O7 pentagonal bipyramid, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 41-59°. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Na(1) and one Se(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Na(2) and one Se(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(3), one Na(5), and one Se(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(3), one Na(4), and one Se(2) atom. In the fifth O site, O(5) is bonded in a distorted water-like geometry to one Na(2), one Na(3), one H(1), and one H(3) atom. In the sixth O site, O(6) is bonded in a distorted water-like geometry to one Na(1), one Na(3), one H(2), and one H(4) atom. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), one Na(3), one Na(5), and one Se(1) atom. In the eighth O site, O(8) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(3), one Na(4), and one Se(2) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Na(5), and one Se(3) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Na(2), one Na(4), one Na(5), and one Se(4) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Na(1), one Na(5), one H(7), and one Se(3) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Na(2), one Na(4), one H(7), and one Se(4) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Na(2), one H(5), and one Se(1) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Na(1), one H(6), and one Se(2) atom. In the fifteenth O site, O(15) is bonded in a distorted trigonal planar geometry to one Na(4), one H(5), and one Se(3) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal planar geometry to one Na(5), one H(6), and one Se(4) atom. In the seventeenth O site, O(17) is bonded in a water-like geometry to one Na(1) and one Se(3) atom. In the eighteenth O site, O(18) is bonded in a distorted water-like geometry to one Na(2) and one Se(4) atom. is represented by the CIF card [CIF]
data_Na5H7(Se2O9)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.070
_cell_length_b   7.467
_cell_length_c   10.040
_cell_angle_alpha   102.683
_cell_angle_beta   99.197
_cell_angle_gamma   100.015
_symmetry_Int_Tables_number   1
_cell_volume   427.824
_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  0.655  0.741  0.190  1.0
  Na  Na1  1  0.346  0.258  0.807  1.0
  Na  Na2  1  0.000  0.001  1.000  1.0
  Na  Na3  1  0.136  0.176  0.400  1.0
  Na  Na4  1  0.869  0.823  0.605  1.0
  H  H5  1  0.953  0.324  0.917  1.0
  H  H6  1  0.050  0.678  0.080  1.0
  H  H7  1  0.146  0.388  0.054  1.0
  H  H8  1  0.854  0.609  0.944  1.0
  H  H9  1  0.288  0.561  0.621  1.0
  H  H10  1  0.713  0.438  0.382  1.0
  H  H11  1  0.500  0.985  0.498  1.0
  Se  Se12  1  0.414  0.799  0.826  1.0
  Se  Se13  1  0.586  0.202  0.176  1.0
  Se  Se14  1  0.249  0.693  0.374  1.0
  Se  Se15  1  0.748  0.306  0.627  1.0
  O  O16  1  0.414  0.773  0.984  1.0
  O  O17  1  0.586  0.228  0.018  1.0
  O  O18  1  0.669  0.875  0.795  1.0
  O  O19  1  0.331  0.126  0.207  1.0
  O  O20  1  0.094  0.296  0.964  1.0
  O  O21  1  0.906  0.703  0.034  1.0
  O  O22  1  0.220  0.915  0.774  1.0
  O  O23  1  0.780  0.084  0.227  1.0
  O  O24  1  0.056  0.823  0.400  1.0
  O  O25  1  0.946  0.179  0.602  1.0
  O  O26  1  0.517  0.840  0.448  1.0
  O  O27  1  0.485  0.160  0.558  1.0
  O  O28  1  0.313  0.563  0.724  1.0
  O  O29  1  0.688  0.437  0.278  1.0
  O  O30  1  0.232  0.520  0.454  1.0
  O  O31  1  0.769  0.480  0.547  1.0
  O  O32  1  0.260  0.617  0.208  1.0
  O  O33  1  0.749  0.389  0.796  1.0
[/CIF]
.