Nitriittiionit

Nitriittiionit are polyatomic anions with the chemical formula NO2-. They consist of one nitrogen atom covalently bonded to two oxygen atoms, with an overall negative charge. The nitrogen atom is in the +3 oxidation state. The ion is resonance-stabilized, meaning the negative charge is delocalized over both oxygen atoms. In terms of molecular geometry, the nitriittiion has a bent or V-shape due to the presence of a lone pair of electrons on the nitrogen atom.

Nitriittiionit are commonly found in the form of salts, such as sodium nitriitti (NaNO2) and potassium nitriitti (KNO2). They are important in various industrial and biological processes. In the food industry, nitriittiionit are used as preservatives, particularly in cured meats, where they help prevent the growth of Clostridium botulinum, a bacterium that produces a deadly toxin. They also contribute to the characteristic pink color and flavor of cured meats. However, concerns exist regarding the potential formation of carcinogenic nitrosamines from nitriittiionit in the presence of amino acids at high temperatures.

In the environment, nitriittiionit can be formed from the oxidation of ammonia, often as an intermediate in the nitrogen cycle. They are also found in wastewater and can be present in drinking water, although levels are typically regulated due to potential health risks, especially for infants, as nitriittiionit can interfere with oxygen transport in the blood (methemoglobinemia). Chemical reactions involving nitriittiionit include their reduction to ammonia or nitrogen gas, and their oxidation to nitraattiionit (NO3-).