Hydrogen polyoxides H2O3 and H2O4 as components of peroxy radical condensate obtained from electro-dissociated water vapor

•Glassy solid is obtained by condensation of electro-dissociated H2O vapor at ∼80 K.•Its main components are hydrogen peroxide HOOH and trioxide HOOOH (and also water).•On heating, the solid decomposes with the liberation of O2, and melts.•HOOOH breaks down mainly during the decomposition in the liquid phase.•HOOOH formation enthalpy in aqueous solution at 220-250 K is −32 ± 4 kcal/mol.

The peroxy radical condensate synthesized from electro-dissociated water vapor has been investigated by the methods of Raman spectroscopy and chemical analysis of its decomposition products. It has been found that hydrogen peroxide H2O2 and trioxide H2O3 (besides water H2O) are the main components. Also hydrogen tetroxide H2O4 is present in the PRC, but its amount is small. On heating, hydrogen tetroxide breaks down at the first step of the condensate decomposition in the solid phase; hydrogen trioxide chiefly disappears at higher temperatures during the decomposition in the liquid phase. These results make it possible to estimate the experimental value of hydrogen trioxide enthalpy of formation in the liquid solution, ΔfH°220-250(H2O3, aq.) = −32 ± 4 kcal/mol, from the thermochemical data, obtained in references Reznitskii et al. (1958) and Skorokhodov et al. (1959, 1961).

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