Studies on hydrogen–oxygen systems in the electrical discharge. IV. Spectroscopic identification of the matrix-stabilized intermediates, H 2 O 3 and H 2 O 4

The infrared absorption of the products from electrically dissociated H 2 O or D 2 O vapor and other hydrogen–oxygen systems trapped at liquid nitrogen temperature was measured between 4000 and 300 cm −1 . Four new absorption bands were found in the deuterated systems at 857, 820, 760, and about 440 cm −1 . By isotopic substitution of 18 O the frequencies are shifted to 806, 775, 717, and ~420 cm −1 as expected for O—O vibrations. In the hydrogen systems this region is obscured by the strong libration bands of H 2 O and H 2 O 2 molecules. Temperature and composition effects show that more than one new species is involved. Accordingly the new spectra are assigned to the often postulated polyoxides, H 2 O 3 and H 2 O 4 , stabilized in the water–peroxide matrix. The more abundant, and also more stable, H 2 O 3 has a half-life of some 5 h at −65 °C.The observed frequencies are consistent with zigzag chain structures linked by single covalent bonds as in hydrogen polysulfides. Relative concentrations of the polyoxides are estimated at 5 to 10 mole% depending on the composition of the starting material. Possible mechanisms of formation and decomposition are discussed.