Molecular formula: C₉H₁₁Cl₃NO₃PS
Molar mass: 350.59 g/mol 
Index of Refraction: 1.565
Density: 1.48 g/cm³
Flash Point: 181.1 °C
Enthalpy of Vaporization: 59.9 kJ/mol
Boiling Point: 375.9 °C at 760 mmHg
Vapour Pressure: 1.63E-05 mmHg at 25 °C
Melting point: 42-44°C
Storage tempreture: Approx 4 °C
Water solubility: Insoluble. 0.00013 g/100 mL
Appearance: White granular crystals
Structure of Chlorpyrifos (CAS NO.2921-88-2):
                       
IUPAC Name: Diethoxy-sulfanylidene-(3,5,6-trichloropyridin-2-yl)oxy-λ5-phosphane
Product Category of Chlorpyrifos (CAS NO.2921-88-2): Organics;Intermediates & Fine Chemicals;Pharmaceuticals;CAlphabetic;CHMethod Specific;Insecticides;Pesticides;AcaricidesAlphabetic;Organophorous

First registered in 1965 and marketed by Dow Chemical Company under the tradenames Dursban and Lorsban, Chlorpyrifos (CAS NO.2921-88-2) was a well known home and garden insecticide, and at one time it was one of the most widely used household pesticides in the US. In 1995, Dow was fined $732,000 for not sending the EPA reports it had received on 249 Dursban poisoning incidents, and in 2003, Dow agreed to pay $2 million - the largest penalty ever in a pesticide case - to the state of New York, in response to a lawsuit filed by the Attorney General to end Dow's illegal advertising of Dursban as "safe". On July 31, 2007, a coalition of farmworker and advocacy groups filed a lawsuit against the EPA seeking to end agricultural use of the chlorpyrifos. The suit claims that the continued use of chlorpyrifos poses an unnecessary risk to farmworkers and their families. In August 2007, Dow's Indian offices were raided by Indian authorities for allegedly bribing officials to allow chlorpyrifos to be sold in the country. In 2008, a federal judge imposed 1000 ft buffer zones around waterways to protect endangered species including salmon. Aerial applications of chlorpyrifos will prohibited within these zones.

 Chlorpyrifos (CAS NO.2921-88-2) is used to control insect pests as Insecticide and acaricide
 

Hazard Symbols: T;N 
Risk Codes: R25;R50/53
R25 :Toxic if swallowed. 
R50/53:Very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment.  
Safety Description: S1/2;S45;S60;S61
S1/2:Keep locked up and out of the reach of children. 
S45:In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) 
S60:This material and its container must be disposed of as hazardous waste. 
S61:Avoid release to the environment. Refer to special instructions / safety data sheets.

 Chlorpyrifos , its cas register number is 2921-88-2. It also can be called O,O-Diethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate ; Phosphorothioic acid O,O-diethyl O-(3,5,6-trichloro-2-pyridinyl) ester ; Chlorpyrifos-ethyl ; Chlorpyritos ; Clorpyrifos ; Dursban HF ; Eradex ; Lorsban 4E-SG ; Pyrinex ; Super I.Q.A.P.T. ; Trichlorpyrphos ; and Dowco 179 .