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Mass spectrum of chlorpyrifos


Toxic, white granule crystals with a strong odor. Chlorpyrifos is an organophosphate type contact Insecticide sold under the brand name of Dursban. Dursban is broad spectrum insecticide used to control cockroaches, chinch bugs, fleas, termites, ants, and ticks. It has been used in pet flea and tick collars.



Chemical structure


Synonyms and Related Terms

chlorpyriphosethyl; chloropyrifos (sp); O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate; Dursban [Dow]: Lorsban; Dowco 179; ENT 27311


  • Toxic by inhalation, ingestion and skin contact.
  • Corrosive to iron, copper and brass.
  • Discolors red dyes.
  • May leave deposits on nearby surfaces.
  • Combustible.
  • Cayman Chemical SDS

Physical and Chemical Properties

Soluble in acetone, benzene, carbon disulfide, carbon tetrachloride, chloroform, diethyl ether, methylene chloride, xylene. Insoluble in water.

Composition C9H11Cl3NO3PS
CAS 2921-88-2
Melting Point 41-42 C
Density 1.398 g/ml
Molecular Weight mol. wt. = 350.6

Resources and Citations

  • Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
  • 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
  • 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
  • Pam Hatchfield, Pollutants in the Museum Environment, Archetype Press, London, 2002