IUPAC Name: Diethyl 2-[methoxy(methylsulfanyl)phosphoryl]sulfanylbutanedioate
Synonyms of Isomalathion (CAS NO.3344-12-5) : ((Methoxy(methylthio)phosphinyl)thio)butanedioic acid diethyl ester ; Butanedioic acid, ((methoxy(methylthio)phosphinothioyl)thio)diethyl ester ; Isomalathion ; Mercaptosuccinic acid diethyl ester, S-ester with O,S-dimethylphosphorodithioate ; S-Methylmalathion
Product Categories: IEnvironmental Standards;Alphabetic;Analytical Standards;Metabolites;Pesticides&Metabolites
CAS NO:3344-12-5
Molecular Formula:C₁₀H₁₉O₆PS₂
Molecular Weight :330.358
Molecular Structure :
Index of Refraction:1.501
Surface Tension: 44.4 dyne/cm
Density: 1.273 g/cm³
Flash Point: 203.9 °C
Enthalpy of Vaporization: 66.64 kJ/mol
Boiling Point: 413.6 °C at 760 mmHg
Vapour Pressure: 4.74E-07 mmHg at 25°C

Preparation Products: guanethidine

A poison by ingestion. When heated to decomposition it emits toxic vapors of PO_x and SO_x.

Hazard Codes Xn,N
Risk Statements 22-50/53
R22: Isomalathion (CAS NO.3344-12-5) is harmful if swallowed. 
R50/53:Very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment.
Safety Statements 24-60-61
S24:Avoid contact with skin. 
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.
RIDADR UN 1208 3/PG 2
RTECS WM8425000

Isomalathion (CAS NO.3344-12-5) is an impurity found in some batches of malathion, depending on its method of preparation. It is significantly more toxic to humans than malathion.