Entangled iodine and hydrogen peroxide formation in ice

Ice-core records show that anthropogenic pollution has increased the global atmospheric concentrations of hydrogen peroxide and iodine since the mid-20th century. Here, for the first time, we demonstrate a highly efficient mechanism that synergistically produces them in icy water conditions. This reaction is aided by a key intermediate IO 2 H, formed by an I - ion with a dissolved O 2 in acidic icy water, which produces both I as well as O 2 H radicals. I recombines with I - o produce I 2 - at a diffusion-limited rate, followed by formation of I 3 - hrough disproportionation, while O 2 H yields H 2 O 2 with I - and a proton dissolved in icy water.