Intermediates are substances formed during the middle stages of a chemical reaction. They are not the starting materials, known as reactants, nor the final products. Instead, intermediates can be unstable and may quickly convert into other substances, playing a crucial role in the overall reaction pathway. In various fields, such as organic chemistry and biochemistry, intermediates help scientists understand how reactions occur. By studying these temporary compounds, researchers can gain insights into reaction mechanisms and improve processes, such as drug development or synthesis of chemicals.