Trioxidane

Trioxidane (systematically named dihydrogen trioxide,), also called hydrogen trioxide is an inorganic compound with the chemical formula H[O]3H (can be written as [H(μ-O3)H] or [H2O3]). It is one of the unstable hydrogen polyoxides. In aqueous solutions, trioxidane decomposes to form water and singlet oxygen: The reverse reaction, the addition of singlet oxygen to water, typically does not occur in part due to the scarcity of singlet oxygen. In biological systems, however, ozone is known to be generated from singlet oxygen, and the presumed mechanism is an antibody-catalyzed production of trioxidane from singlet oxygen. Trioxidane can be obtained in small, but detectable, amounts in reactions of ozone and hydrogen peroxide, or by the electrolysis of water. Larger quantities have been prepared by the reaction of ozone with organic reducing agents at low temperatures in a variety of organic solvents, such as the anthraquinone process. It is also formed during the decomposition of organic hydrotrioxides (ROOOH). Alternatively, trioxidane can be prepared by reduction of ozone with 1,2-diphenylhydrazine at low temperature. Using a resin-bound version of the latter, relatively pure trioxidane can be isolated as a solution in organic solvent. Preparation of high purity solutions is possible using the methyltrioxorhenium(VII) catalyst. In acetone-d6 at −20 °C, the characteristic 1H NMR signal of trioxidane could be observed at a chemical shift of 13.1 ppm. Solutions of hydrogen trioxide in diethyl ether can be safely stored at −20 °C for as long as a week. The reaction of ozone with hydrogen peroxide is known as the "peroxone process". This mixture has been used for some time for treating groundwater contaminated with organic compounds. The reaction produces H2O3 and H2O5. In 1970-75, Giguère et al. observed infrared and Raman spectra of dilute aqueous solutions of trioxidane. In 2005, trioxidane was observed experimentally by microwave spectroscopy in a supersonic jet. The molecule exists in a skewed structure, with an oxygen–oxygen–oxygen–hydrogen dihedral angle of 81.