Parathion

Mass spectrum of parathion

Description

A highly toxic organic phosphate insecticide. Parathion was introduced in 1947. The pale yellow liquid acts as a cholinesterase inhibitor. It interrupts the function of the central nervous system and causes death by respiratory failure.

FTIR

Synonyms and Related Terms

O,O-diethyl-O,p-nitrophenyl phosphorothioate; ethyl parathion; O,O-diethyl-p-nitrophenyl thiophosphate; AATP; Niran; Penncap-E

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
• One of the 'Dirty Dozen' named by the Stockholm Convention

Physical and Chemical Properties

Soluble in ester, alcohols, ketones, ethers, aromatic hydrocarbons, oils. Slightly soluble in water. Insoluble in petroleum ether, kerosene.

Composition	(C2H5O)2P(S)OC6H4NO2
CAS	56-38-2
Melting Point	6 C
Density	1.26 g/ml
Molecular Weight	mol. wt. = 291.27
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