A reaction intermediate is a temporary species formed during a chemical reaction. It exists between the reactants and the final products, often having a short lifespan. These intermediates can be unstable and may quickly convert into other substances, playing a crucial role in the reaction mechanism. Understanding reaction intermediates helps chemists predict the pathway of a reaction. They can provide insights into the energy changes and the steps involved, which is essential for fields like organic chemistry and biochemistry. Identifying these intermediates can also aid in the development of catalysts and new synthetic methods.