Hydroxyl radical

The hydroxyl radical (OH radical HO · ) is comprised of a hydrogen and one oxygen atom, and is one of the most common free radicals in the atmosphere. It plays an important role for the degradation of certain greenhouse gases, such as methane (CH4 ), ozone, trace gases and air pollutants and can be described as a chemical detergent of the atmosphere. Other than the hydroxide ion OH carries the hydroxyl radical, no charge, the oxygen atom has one less electron and thereby a single, unpaired electron.

The hydroxyl radical generated in the atmosphere of ozone and water molecules when struck by ultraviolet rays. 1963 OH was measured by radio- astronomical methods also in the interstellar medium. Besides, it can also in the photolytic decomposition of hydrogen:

And the result of nitrous acid:

These reactions are, inter alia, of importance in the formation of tropospheric ozone.

In many combustion processes, the OH radical plays an important role, such as in the oxyhydrogen reaction:

And other reactions

The hydroxyl radical is not with the negatively charged OH - ion ( see hydroxides ) or with the OH group (see hydroxy group ) to be confused.