Ionic liquids are ionic, salt-like materials that are liquid below 100 °C. Their use can be classified as process chemicals (e.g., solvents, separation media) and performance chemicals (e.g., electrolytes, lubricants). Sigma-Aldrich offers a market-leading range of ammonium, imidazolium-, phosphonium-, pyridinium-, pyrrolidinium-, and sulfonium-based ionic liquids.