text: Phosphate esters have the general structure P(=O)(OR) feature P(V). Such species are of technological importance as flame retardant agents, and plasticizers. Lacking a P−C bond, these compounds are in the technical sense not organophosphorus compounds but esters of phosphoric acid.  Many derivatives are found in nature, such as phosphatidylcholine. Phosphate ester are synthesized by alcoholysis of phosphorus oxychloride.  A variety of mixed amido-alkoxo derivatives are known, one medically significant example being the anti-cancer drug cyclophosphamide.  Also derivatives containing the thiophosphoryl group (P=S) include the pesticide malathion.  The organophosphates prepared on the largest scale are the zinc dithiophosphates, as additives for motor oil.  Several million kilograms of this coordination complex are produced annually by the reaction of phosphorus pentasulfide with alcohols.
  In the environment, these compounds break down via hydrolysis to eventually afford phosphate and the organic alcohol or amine from which they are derived.