Phosphorus pentachloride is mainly used as a chlorination reagent for alcohols, carboxylic acids, amides, aldehydes, ketones, enols, and Beckmann rearrangement reagents. It is used as a chlorination agent and catalyst in organic synthesis, and is used in the production of medicines, dyes, and chemical fibers. It is also the raw material for the production of phosphazene chloride and phosphorus oxychloride.

The structural unit of phosphorus pentachloride in solid state can be written as PCl4+, PCl6-, cesium chloride crystal structure, the two ions are tetrahedral and octahedral structures respectively, the phosphorus atom in the cation is sp3 hybridization, and the phosphorus in the anion is sp3d2 hybridization. Phosphorus pentachloride in gaseous and liquid states has a single molecular structure, and the molecules are triangular and bipyramidal, which is consistent with the prediction of VSEPR theory.

Molecular structure of PCl5

The molecular structure in solution is related to concentration and solvent. When dissolved in polar solvents (such as nitromethane, nitrobenzene), phosphorus pentachloride undergoes self-dual ionization.