[en] Hydrated hyponitrates of calcium, strontium, barium were prepared by exchange reaction of sodium hyponitrate with the corresponding chloride in aqueous solution. Anhydrous hyponitrates of alkaline - earth metals MN₂O₃ (M-Ca, Sr, Ba) were prepared by the method of vacuum-thermal dehydration: CaN₂O₃x4H₂O and SrN₂O₃x2H₂O at 200 deg C, BaN₂O₃xH₂O at 120 deg C. Thermal decomposition of MN₂O₃ occurs in the range of 230-350 deg C and it is accompanied by intermediate formation of MN₂O₂

[en] Hyponitrates of alkali metals M₂N₂O₃ (M=Li-Cs) are prepared by the interaction of free NH₂OH with ethyl-nitrate in the presence of ethylate or hydroxide of alkali metal in the medium of absolute ethanol. A technique to prepare hyponitrates of K and Cs by the exchange reaction of Li₂N₂O₃ with fluorides in an aqueous solution is developed. All hyponitrates obtained are singled out in non-solvated state. IR spectra of M₂N₂O₃ correspond to the vibrations of flat anion ONNO₂^2- with the symmetry Csub(s). The effect of cation dimension upon the spectrum character has not been detected. Thermal decomposition of M₂N₂O₃ takes place in the range of 290-370 deg C and is accompanied by intermediate formation of M₂N₂O₂

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