Used primarily in organic synthesis as a reagent for introducing phosphate groups into molecules. It plays a role in the preparation of phosphoramidates and other phosphorus-containing compounds, which are valuable in medicinal chemistry and agrochemical research. Additionally, it serves as a key intermediate in the development of flame retardants and plasticizers due to its phosphorus and chlorine content. Its reactivity with alcohols and amines makes it useful in modifying biomolecules for biochemical studies.