The compound 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 6-coordinate geometry to one O(13), one O(16), one O(18), one O(4), one O(7), and one O(9) atom. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(10), one O(14), one O(15), one O(17), one O(3), and one O(8) atom. In the third Na site, Na(3) is bonded in a 6-coordinate geometry to one O(11), one O(12), one O(14), one O(15), one O(16), and one O(4) atom. In the fourth Na site, Na(4) is bonded to one O(1), one O(12), one O(4), one O(5), and one O(6) atom to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Se(2)O4 tetrahedra, corners with two equivalent Se(1)O4 tetrahedra, and corners with two equivalent Se(4)O4 tetrahedra. In the fifth Na site, Na(5) is bonded in a 5-coordinate geometry to one O(11), one O(2), one O(3), one O(5), and one O(6) atom. There are seven inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(15) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(16) atom. In the third H site, H(3) is bonded in a single-bond geometry to one O(7) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(8) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(10) and one O(15) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one O(16) atom. In the seventh H site, H(7) is bonded in a distorted linear geometry to one O(1) and one O(17) atom. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to one O(1), one O(5), one O(7), and one O(9) atom to form SeO4 tetrahedra that share corners with two equivalent Na(4)O5 trigonal bipyramids. In the second Se site, Se(2) is bonded to one O(10), one O(2), one O(6), and one O(8) atom to form SeO4 tetrahedra that share  a cornercorner with one Na(4)O5 trigonal bipyramid. In the third Se site, Se(3) is bonded in a tetrahedral geometry to one O(11), one O(13), one O(17), and one O(3) atom. In the fourth Se site, Se(4) is bonded to one O(12), one O(14), one O(18), and one O(4) atom to form SeO4 tetrahedra that share corners with two equivalent Na(4)O5 trigonal bipyramids. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Na(4), one H(7), and one Se(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Na(5) and one Se(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(2), one Na(5), and one Se(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal pyramidal geometry to one Na(1), one Na(3), one Na(4), and one Se(4) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Na(4), one Na(5), and one Se(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Na(4), one Na(5), and one Se(2) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Na(1), one H(3), and one Se(1) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one Na(2), one H(4), and one Se(2) atom. In the ninth O site, O(9) is bonded in a distorted water-like geometry to one Na(1) and one Se(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Na(2), one H(5), and one Se(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Na(3), one Na(5), and one Se(3) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Na(3), one Na(4), and one Se(4) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Na(1) and one Se(3) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 150 degrees geometry to one Na(2), one Na(3), and one Se(4) atom. In the fifteenth O site, O(15) is bonded in a distorted water-like geometry to one Na(2), one Na(3), one H(1), and one H(5) atom. In the sixteenth O site, O(16) is bonded in a distorted water-like geometry to one Na(1), one Na(3), one H(2), and one H(6) atom. In the seventeenth O site, O(17) is bonded in a 1-coordinate geometry to one Na(2), one H(7), and one Se(3) atom. In the eighteenth O site, O(18) is bonded in a bent 120 degrees geometry to one Na(1) and one Se(4) atom. is represented by the CIF file [CIF]
data_Na5H7(Se2O9)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.200
_cell_length_b   7.254
_cell_length_c   10.277
_cell_angle_alpha   99.138
_cell_angle_beta   96.707
_cell_angle_gamma   99.918
_symmetry_Int_Tables_number   1
_cell_volume   444.534
_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  0.872  0.287  0.332  1.0
  Na  Na1  1  0.111  0.723  0.667  1.0
  Na  Na2  1  0.529  0.988  0.489  1.0
  Na  Na3  1  0.409  0.825  0.129  1.0
  Na  Na4  1  0.604  0.153  0.888  1.0
  H  H5  1  0.353  0.616  0.452  1.0
  H  H6  1  0.648  0.390  0.563  1.0
  H  H7  1  0.007  0.058  0.125  1.0
  H  H8  1  0.990  0.925  0.893  1.0
  H  H9  1  0.523  0.662  0.587  1.0
  H  H10  1  0.474  0.338  0.431  1.0
  H  H11  1  0.208  0.434  0.891  1.0
  Se  Se12  1  0.271  0.324  0.139  1.0
  Se  Se13  1  0.718  0.660  0.860  1.0
  Se  Se14  1  0.088  0.209  0.689  1.0
  Se  Se15  1  0.912  0.793  0.324  1.0
  O  O16  1  0.257  0.494  0.052  1.0
  O  O17  1  0.704  0.482  0.939  1.0
  O  O18  1  0.268  0.075  0.731  1.0
  O  O19  1  0.737  0.936  0.277  1.0
  O  O20  1  0.441  0.180  0.096  1.0
  O  O21  1  0.557  0.814  0.901  1.0
  O  O22  1  0.999  0.175  0.088  1.0
  O  O23  1  0.997  0.798  0.915  1.0
  O  O24  1  0.278  0.396  0.301  1.0
  O  O25  1  0.722  0.603  0.697  1.0
  O  O26  1  0.840  0.120  0.723  1.0
  O  O27  1  0.161  0.882  0.284  1.0
  O  O28  1  0.093  0.272  0.543  1.0
  O  O29  1  0.919  0.808  0.488  1.0
  O  O30  1  0.395  0.701  0.539  1.0
  O  O31  1  0.603  0.301  0.477  1.0
  O  O32  1  0.184  0.438  0.792  1.0
  O  O33  1  0.816  0.569  0.246  1.0
[/CIF]
.
The compound 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 6-coordinate geometry to one O(13), one O(16), one O(18), one O(4), one O(7), and one O(9) atom. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(10), one O(14), one O(15), one O(17), one O(3), and one O(8) atom. In the third Na site, Na(3) is bonded in a 6-coordinate geometry to one O(11), one O(12), one O(14), one O(15), one O(16), and one O(4) atom. In the fourth Na site, Na(4) is bonded to one O(1), one O(12), one O(4), one O(5), and one O(6) atom to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Se(2)O4 tetrahedra, corners with two equivalent Se(1)O4 tetrahedra, and corners with two equivalent Se(4)O4 tetrahedra. In the fifth Na site, Na(5) is bonded in a 5-coordinate geometry to one O(11), one O(2), one O(3), one O(5), and one O(6) atom. There are seven inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(15) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(16) atom. In the third H site, H(3) is bonded in a single-bond geometry to one O(7) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(8) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(10) and one O(15) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one O(16) atom. In the seventh H site, H(7) is bonded in a distorted linear geometry to one O(1) and one O(17) atom. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to one O(1), one O(5), one O(7), and one O(9) atom to form SeO4 tetrahedra that share corners with two equivalent Na(4)O5 trigonal bipyramids. In the second Se site, Se(2) is bonded to one O(10), one O(2), one O(6), and one O(8) atom to form SeO4 tetrahedra that share  a cornercorner with one Na(4)O5 trigonal bipyramid. In the third Se site, Se(3) is bonded in a tetrahedral geometry to one O(11), one O(13), one O(17), and one O(3) atom. In the fourth Se site, Se(4) is bonded to one O(12), one O(14), one O(18), and one O(4) atom to form SeO4 tetrahedra that share corners with two equivalent Na(4)O5 trigonal bipyramids. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Na(4), one H(7), and one Se(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Na(5) and one Se(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(2), one Na(5), and one Se(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal pyramidal geometry to one Na(1), one Na(3), one Na(4), and one Se(4) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Na(4), one Na(5), and one Se(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Na(4), one Na(5), and one Se(2) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Na(1), one H(3), and one Se(1) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one Na(2), one H(4), and one Se(2) atom. In the ninth O site, O(9) is bonded in a distorted water-like geometry to one Na(1) and one Se(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Na(2), one H(5), and one Se(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Na(3), one Na(5), and one Se(3) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Na(3), one Na(4), and one Se(4) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Na(1) and one Se(3) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 150 degrees geometry to one Na(2), one Na(3), and one Se(4) atom. In the fifteenth O site, O(15) is bonded in a distorted water-like geometry to one Na(2), one Na(3), one H(1), and one H(5) atom. In the sixteenth O site, O(16) is bonded in a distorted water-like geometry to one Na(1), one Na(3), one H(2), and one H(6) atom. In the seventeenth O site, O(17) is bonded in a 1-coordinate geometry to one Na(2), one H(7), and one Se(3) atom. In the eighteenth O site, O(18) is bonded in a bent 120 degrees geometry to one Na(1) and one Se(4) atom. is represented by the CIF file [CIF]
data_Na5H7(Se2O9)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.200
_cell_length_b   7.254
_cell_length_c   10.277
_cell_angle_alpha   99.138
_cell_angle_beta   96.707
_cell_angle_gamma   99.918
_symmetry_Int_Tables_number   1
_cell_volume   444.534
_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  0.872  0.287  0.332  1.0
  Na  Na1  1  0.111  0.723  0.667  1.0
  Na  Na2  1  0.529  0.988  0.489  1.0
  Na  Na3  1  0.409  0.825  0.129  1.0
  Na  Na4  1  0.604  0.153  0.888  1.0
  H  H5  1  0.353  0.616  0.452  1.0
  H  H6  1  0.648  0.390  0.563  1.0
  H  H7  1  0.007  0.058  0.125  1.0
  H  H8  1  0.990  0.925  0.893  1.0
  H  H9  1  0.523  0.662  0.587  1.0
  H  H10  1  0.474  0.338  0.431  1.0
  H  H11  1  0.208  0.434  0.891  1.0
  Se  Se12  1  0.271  0.324  0.139  1.0
  Se  Se13  1  0.718  0.660  0.860  1.0
  Se  Se14  1  0.088  0.209  0.689  1.0
  Se  Se15  1  0.912  0.793  0.324  1.0
  O  O16  1  0.257  0.494  0.052  1.0
  O  O17  1  0.704  0.482  0.939  1.0
  O  O18  1  0.268  0.075  0.731  1.0
  O  O19  1  0.737  0.936  0.277  1.0
  O  O20  1  0.441  0.180  0.096  1.0
  O  O21  1  0.557  0.814  0.901  1.0
  O  O22  1  0.999  0.175  0.088  1.0
  O  O23  1  0.997  0.798  0.915  1.0
  O  O24  1  0.278  0.396  0.301  1.0
  O  O25  1  0.722  0.603  0.697  1.0
  O  O26  1  0.840  0.120  0.723  1.0
  O  O27  1  0.161  0.882  0.284  1.0
  O  O28  1  0.093  0.272  0.543  1.0
  O  O29  1  0.919  0.808  0.488  1.0
  O  O30  1  0.395  0.701  0.539  1.0
  O  O31  1  0.603  0.301  0.477  1.0
  O  O32  1  0.184  0.438  0.792  1.0
  O  O33  1  0.816  0.569  0.246  1.0
[/CIF]
.