The chemical formula of phosphorus oxychloride is POCl3, CAS No. 10025-87-3. It is a colorless to light yellow liquid at room temperature, with a pungent odor and strong volatility. It is easily soluble in organic solvents such as benzene and carbon disulfide, and will quickly hydrolyze into phosphoric acid and hydrogen chloride when exposed to water. The reaction is violent and exothermic, and may be accompanied by smoke. It is more corrosive than phosphorus trichloride and can cause deep burns when in contact with the skin. Inhalation of vapor can seriously irritate the respiratory tract and lungs, and is a toxic chemical. Storage must be in corrosion-resistant sealed containers, placed in a dry and ventilated place, and contact with water and alkali substances is strictly prohibited. Industrially, it is mostly used in the semiconductor industry (preparation of photoresist, dopants), organic synthesis (production of phosphate plasticizers, flame retardants), and can also be used as a catalyst for medicine and dye synthesis, and can also be used to prepare high-purity phosphoric acid.