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Mass spectrum of malathion


A dark yellow liquid that is used as an Insecticide. Malathion is an organophosphate compound that acts as a cholinesterase inhibitor. It has an unpleasant, Sulfur type odor and can be corrosive to Iron. Malathion has been used for control of cockroaches, treatment of head lice, and the aerial spraying to eradicate the Mediterranean fruit fly. Malathion biodegrades to form nontoxic compounds.



Chemical structure


Synonyms and Related Terms

S-[1,2-bis(ethoxycarbonyl)ethyl]O,O-dimethylphosphorodithioate; carbofos; mercaptothion; [(dimethoxyphosphinothioyl)thio]butanedioic acid diethyl ester; insecticide no. 4049; Cythion [American Cyanamid]


  • Relatively low toxicity for mammals.
  • Overexposure through inhalation and skin absorption can causes irritation and/or vision/breathing problems. LD50=2800 mg/kg
  • Potential teratogen.
  • Combustible.
  • Corrodes iron, steel, tin, lead, and copper. May discolor organic red dyes.
  • WinField: SDS

Physical and Chemical Properties

Miscible with alcohols, ketones, ether, aromatic hydrocarbons and oils. Slightly soluble in water. Decomposes with acids or bases to produce sulfur compounds.

Composition C10H19O6PS2
CAS 121-75-5
Melting Point 2.9 C
Density 1.23 g/ml
Molecular Weight mol. wt. = 330.4
Boiling Point 156-157 C

Resources and Citations

  • Lynda A. Zycherman, J.Richard Schrock, A Guide to Museum Pest Control, FAIC and Association of Systematics Collections, Washington DC, 1988
  • J. Dawson, CCI Technical Bulletin, 'Solving Museum Insect Problems: Chemical Control' , Canadian Conservation Institute, Ottawa, No. 15

Sources Checked for Data in Record

  • Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
  • The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry # 5740
  • Pam Hatchfield, Pollutants in the Museum Environment, Archetype Press, London, 2002
  • G.Caneva, M.P.Nugari, O.Salvadori, Biology in the Conservation of Works of Art, ICCROM, Rome, 1991