Generation and Characterization of Sulfurous Acid (H2SO3) and of Its Radical Cation as Stable Species in the Gas Phase

Sulfurous acid (H 2 SO 3 ) and its radical cation H 2 SO are stable molecules: this has been shown unambiguously by neutralization‐reionization. MS experiments and by ab initio calculations. That these species are non‐existent in solution is not due to intrinsic factors, but to the medium. The key experiment, with deuterated starting material and product, is shown below. equation image