In the structure of the title compound, C6H18N22+. 2H(2)PO(3)(-),the hexame
thylenediammonium dication has a center of symmetry and the asymmetric unit
contains half of the dication and one hydrogenphosphite anion. The (PD)OD
H . . .O(-P) and N-H . . .O(-P) hydrogen bonds link ammonium and hydrogenph
osphite groups to form a two-dimensional hydrogen-bonded network. Layers ar
e linked covalently into pillars by bifunctional diammonium moieties, makin
g a three-dimensional framework.