Acetonitrile (CH₃CN) is a colorless, volatile, and flammable liquid with a sweet, ether-like odor. It is widely used as a polar aprotic solvent in organic synthesis and chromatography, especially in HPLC (High-Performance Liquid Chromatography). Acetonitrile is miscible with water and many organic solvents. It is toxic in high concentrations and should be handled with proper safety precautions.