... Product Name Chlopyrifos Chemical Name O,O-diethyl O-(3,5,6-trichloro-2-pyridinyl) phosphorothioate Empirical Formula C9H11Cl3NO3PS CAS Number ... 2921-88-2 Molecular Weight 350.5 Formulation 97%TC, 480g/L EC Applications Chlorpyrifos is a broad spectrum insecticide ... , flea beetles, flies, termites, fire ants, and lice. Chlopyrifos 48% EC