The destructive action of hydroxyl radicals has been implicated in several neurological autoimmune diseases such as HAND when immune cells become over-activated and toxic to neighboring healthy cells. Macrophages and microglia most frequently generate this compound when exposed to very specific pathogens, such as certain bacteria. Hydroxyl radicals can occasionally be produced as a byproduct of immune action. The unpaired electron of the hydroxyl radical is officially represented by a middle dot, In organic synthesis, hydroxyl radicals are most commonly generated by photolysis of 1-hydroxy-2(1 H)-pyridinethione. It is also important in the field of radiation chemistry, since it leads to the formation of hydrogen peroxide and oxygen, which can enhance corrosion and SCC in coolant systems subjected to radioactive environments. Most notably the hydroxyl radicals are produced from the decomposition of hydroperoxides (ROOH) or, in atmospheric chemistry, by the reaction of excited atomic oxygen with water.

The hydroxyl radical is very stable as a dilute gas, but it decays very rapidly in the condensed phase. The hydroxyl radical is the diatomic molecule

Ozone 9 standard