The nitrite ion, represented as NO2-, is a negatively charged polyatomic ion composed of one nitrogen atom and two oxygen atoms. It is commonly found in various chemical compounds and plays a significant role in biological processes, such as the nitrogen cycle. In aqueous solutions, NO2- can act as a reducing agent and is often used in food preservation and as a reagent in chemical reactions. It is important to note that high concentrations of nitrites can be harmful to health, as they can form potentially toxic compounds in the body.