NMR and Raman spectral studies of ammonium hydrogen selenites single crystals

The chemical composition and peculiarities of the structure of a salt that precipitates from aqueous solution of NH 4HSeO 3 at the 25 °C was studied by NMR and Raman spectroscopy methods using the single crystal samples with different heavy water contents. It was proved that this salt is actually monohydrate of hydrogen selenite, NH 4HSeO 3⋅H 2O but not trihydrate of pyroselenite, (NH 4) 2Se 2O 5⋅3H 2O as was assumed previously based on the data cited in the literature.