Ammonium salts are a class of compounds that can form stable ionic liquids when combined with appropriate anions under certain conditions. They are known for their low volatility and high thermal stability, making them suitable for a wide range of applications. In ionic liquids, ammonium salts can act as solvents, catalysts, or electrolytes, enabling processes such as electrochemical reactions and separations. Their ability to dissolve a variety of substances, including metals and polymers, makes them valuable in materials science and catalysis. Ammonium-based ionic liquids are also being explored for use as green solvents in energy storage systems and chemical syntheses.