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.
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. The Na(1)-O(13) bond length is 2.46 Å. The Na(1)-O(16) bond length is 2.37 Å. The Na(1)-O(18) bond length is 2.41 Å. The Na(1)-O(4) bond length is 2.49 Å. The Na(1)-O(7) bond length is 2.76 Å. The Na(1)-O(9) bond length is 2.58 Å. 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. The Na(2)-O(10) bond length is 2.50 Å. The Na(2)-O(14) bond length is 2.30 Å. The Na(2)-O(15) bond length is 2.32 Å. The Na(2)-O(17) bond length is 2.68 Å. The Na(2)-O(3) bond length is 2.52 Å. The Na(2)-O(8) bond length is 2.73 Å. 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. The Na(3)-O(11) bond length is 2.82 Å. The Na(3)-O(12) bond length is 2.83 Å. The Na(3)-O(14) bond length is 2.94 Å. The Na(3)-O(15) bond length is 2.27 Å. The Na(3)-O(16) bond length is 2.26 Å. The Na(3)-O(4) bond length is 2.67 Å. 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. The Na(4)-O(1) bond length is 2.40 Å. The Na(4)-O(12) bond length is 2.38 Å. The Na(4)-O(4) bond length is 2.33 Å. The Na(4)-O(5) bond length is 2.62 Å. The Na(4)-O(6) bond length is 2.61 Å. 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. The Na(5)-O(11) bond length is 2.38 Å. The Na(5)-O(2) bond length is 2.32 Å. The Na(5)-O(3) bond length is 2.40 Å. The Na(5)-O(5) bond length is 2.46 Å. The Na(5)-O(6) bond length is 2.45 Å. 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. The H(1)-O(15) bond length is 0.98 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(16) atom. The H(2)-O(16) bond length is 0.98 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(7) atom. The H(3)-O(7) bond length is 0.99 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(8) atom. The H(4)-O(8) bond length is 0.99 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(10) and one O(15) atom. The H(5)-O(10) bond length is 1.73 Å. The H(5)-O(15) bond length is 0.99 Å. In the sixth H site, H(6) is bonded in a single-bond geometry to one O(16) atom. The H(6)-O(16) bond length is 0.98 Å. In the seventh H site, H(7) is bonded in a distorted linear geometry to one O(1) and one O(17) atom. The H(7)-O(1) bond length is 1.62 Å. The H(7)-O(17) bond length is 1.02 Å. 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. The Se(1)-O(1) bond length is 1.65 Å. The Se(1)-O(5) bond length is 1.65 Å. The Se(1)-O(7) bond length is 1.81 Å. The Se(1)-O(9) bond length is 1.65 Å. 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. The Se(2)-O(10) bond length is 1.67 Å. The Se(2)-O(2) bond length is 1.62 Å. The Se(2)-O(6) bond length is 1.66 Å. The Se(2)-O(8) bond length is 1.82 Å. 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. The Se(3)-O(11) bond length is 1.66 Å. The Se(3)-O(13) bond length is 1.64 Å. The Se(3)-O(17) bond length is 1.78 Å. The Se(3)-O(3) bond length is 1.67 Å. 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. The Se(4)-O(12) bond length is 1.69 Å. The Se(4)-O(14) bond length is 1.67 Å. The Se(4)-O(18) bond length is 1.66 Å. The Se(4)-O(4) bond length is 1.70 Å. 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.