Thionyl chloride is a colorless or yellowish liquid under normal temperature and pressure. It has a pungent odor and is easy to decompose into sulfur dioxide and hydrogen chloride when meeting water. It is dissolved in benzene, chloroform and carbon tetrachloride and heated to 150 ℃ ° C starts to decompose, 500 °C is completely decomposed. Thionyl chloride can react with hydroxyl phenol or alcohol to form corresponding chloride; It reacted with Grignard reagent to form corresponding sulfoxide compounds. The molecular configuration of thionyl chloride is conical, in which the sulfur (VI) center contains a pair of lone pair electrons. Thionyl chloride is an important organic chemical intermediate, which is mainly used in medicine, pesticide, dye industry and organic synthesis industry as chlorinating agent. Pesticide industry is the main consumption field of thionyl chloride in China, which is mainly used in the production of antipotamide, pentrin, fenvalerate, fenvalerate, fenpropathrin, fenpropathrin, Isocarbophos, fenpropathrin, endosulfan, deltamethrin, methoxychlorpyrifos, oxazolidone, quizalofop and warfarin. Because thionyl chloride can strongly react with water, it can also react with hydrated salt of metal chloride to produce anhydrous metal chloride.