Nitrogen trioxide, with the chemical formula N2O3, is a blue solid that can also exist as a gas. It is formed by the reaction of nitrogen dioxide (NO2) and nitric oxide (NO) at low temperatures. This compound is known for its role in atmospheric chemistry and can contribute to the formation of acid rain. In terms of safety, nitrogen trioxide is considered toxic and can be harmful if inhaled. It is primarily used in research and industrial applications, particularly in the production of nitric acid and other nitrogen-based compounds. Proper handling and storage are essential to minimize health risks.