Nitrogenoksid

Nitrogenoksid is a chemical term used for oxides of nitrogen. It most commonly refers to nitric oxide, NO, a diatomic molecule that is a free radical. NO is a colorless gas at room temperature with a boiling point of about −151.8 °C. It is slightly soluble in water and is paramagnetic due to an unpaired electron. In the broader context, nitrogen oxides (NOx) include NO, NO2, N2O3, N2O4, and related species formed during oxidation of nitrogen.

Occurrence and roles: NO is produced naturally by lightning and during combustion in engines and power plants. Biologically, nitric oxide is produced by nitric oxide synthase enzymes and acts as an important signaling molecule in humans and other organisms, regulating vascular tone, neurotransmission, and immune response.

Production and uses: Industrial production of NO is mainly via controlled oxidation of ammonia in the Ostwald process, and it is further oxidized to NO2 and ultimately to nitric acid. In medicine, inhaled NO serves as a selective pulmonary vasodilator to treat hypoxic respiratory failure. In research, NO is used as a signaling mediator and in studies of redox biology.

Environmental and safety notes: In the atmosphere, NO quickly reacts with oxygen to form NO2, which contributes to smog and acid rain precursors. NO is toxic at high concentrations and reacts with biological molecules, requiring careful handling in industrial settings.