page_title: Organophosphorus compound
section_title: Phosphate esters and amides
hierarchical_section_title: Organophosphorus compound / Organophosphorus(V) compounds, main categories / Phosphate esters and amides
caption_attribution_description: English: range of phosphate structures including bio
context_page_description: Organophosphorus compounds are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbons that persist in the environment. Some organophosphorus compounds are highly effective insecticides, although some are extremely toxic to humans, including sarin and VX nerve agents.
  Organophosphorus chemistry is the corresponding science of the properties and reactivity of organophosphorus compounds. Phosphorus, like nitrogen, is in group 15 of the periodic table, and thus phosphorus compounds and nitrogen compounds have many similar properties. The definition of organophosphorus compounds is variable, which can lead to confusion. In industrial and environmental chemistry, an organophosphorus compound need contain only an organic substituent, but need not have a direct phosphorus-carbon bond. Thus a large proportion of pesticides, are often included in this class of compounds.
  Phosphorus can adopt a variety of oxidation states, and it is general to classify organophosphorus compounds based on their being derivatives of phosphorus(V) vs phosphorus(III), which are the predominant classes of compounds.
context_section_description: Phosphate esters have the general structure P(=O)(OR)₃ 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.
caption: Illustrative organophosphates and related compounds: phosphatidylcholine, triphenylphosphate, cyclophosphamide, parathion, and zinc dithiophosphate.
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