Parathion

Description

A highly toxic organic phosphate. Parathion was developed in the 1940s by Gerhard Schrader at IG Farben in Germany. Distributed as a pesticide in the US in 1948, parathion acts as a cholinesterase inhibitor. However it affects both insects and mammals, which means it interrupts the function of the central nervous system and causes death by respiratory failure. The use of parathion has been banned or restricted worldwide.

FTIR

Mass spectrum

Synonyms and Related Terms

O,O-diethyl-O,p-nitrophenyl phosphorothioate; O,O-diethyl-p-nitrophenyl thiophosphate; diethyl parathion; parathion-ethyl; AATP; E605; Niran; Penncap-E; Alkron; alleron; Bladan; Corothion; Orthosphos; Panthion; Paramar; Phoskil; Stathion; Thiosphos

Personal Risks

• Highly toxic by skin contact, inhalation or ingestion.
• Flammable. Flash point = 120-160 C.
• NIH: Compound summary

Environmental Risks

• Persistent organic pollutant; resists bacterial and chemical breakdown processes
• Biomagnifies as it is passed up the food chain
• Toxic to almost all forms of life
• One of the 'Dirty Dozen' named by the Stockholm Convention

Physical and Chemical Properties

• Distributed as a brown liquid that smells like rotten eggs; also sold a powders, dust and granules
• Its darken in sunlight
• Soluble in ester, alcohols, ketones, ethers, aromatic hydrocarbons, oils. Slightly soluble in water.
• Insoluble in petroleum ether, kerosene.
• Composition = (C₂H₅O)₂P(S)OC₆H₄NO₂ (mol.wt. = 291.27 g/m)
• CAS = 56-38-2
• Melting Point = 6 C
• Density = 1.26 g/ml
• Refractive Index = 1.5367
• Boiling Point = 375 C

Resources and Citations

• MuseumPests.net: Pesticide Database
• Encyclopedia Britannica, http://www.britannica.com Comment:parathion [Accessed March 26, 2002].
• The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 6897
• Wikipedia: Parathion Accessed Nov 2026