Thionyl chloride is widely used in organic synthesis as a chlorinating agent. It converts alcohols and carboxylic acids into alkyl chlorides and acyl chlorides, respectively, which are essential intermediates in the production of pharmaceuticals, agrochemicals, and dyes. It is also employed in the preparation of inorganic chlorides and as a reagent in the synthesis of lithium-thionyl chloride batteries, which are known for their high energy density and long shelf life. Additionally, it serves as a dehydrating agent in certain chemical reactions, helping to remove water and drive reactions to completion. Its versatility makes it a valuable tool in both industrial and laboratory settings.