Table 1. Variation in Phosphorus Ester Types of Organophosphorus Insecticides

Structure Type Organophosphorus Insecticides

R1O

P

OR3R2O

O Phosphate Chlorfenvinphos, dichlorvos, dicrotophos, dimethylvinphos, hetenophos,mevinphos, monocrotophos, naled, phosphamidon, propaphos,tetrachlorvinphos

R1O

P

OR3R2O

S O−R1 O−R2 O−R3

Phosphorothioate∗1Phosphorothionate∗2

Chlorethoxyphos, chlorpyrifos, chlorpyrifos-methyl, coumaphos, cyanophos,diazinon, ethrimfos, famphur, fenitrothion, fenthion, flupyrazofos, isazofos,isoxathion, methacrifos, parathion, parathion-methyl, phoxim,pirimiphos-ethyl, pirimiphos-methyl, pyridaphenthion, quinalphos, sulfotep,tebupirimfos, temephos, triazophos

R1O

P

SR3R2O

O O−R1 O−R2 S−R3

Phosphorothioate∗1Phosphorothiolate∗2

Azamethiphos, demeton-S-methyl, omethoate, oxydemeton-methyl, profenofos,pyraclofos, vamidothion

R1O

P

SR3R2O

S O−R1 O−R2 S−R3

Phosphorodithioate∗1Phosphorothiolothionate∗2

Azinphos-ethyl, azinphos-methyl, chlormephos, dimethoate, disulfoton, ethion,formothion, malathion, mecarbam, methidathion, phenthoate, phorate,phosalone, phosmet, prothiofos, sulprofos, terbufos, thiometon

R1O

P

SR3R2S

O O−R1 S−R2 S−R3

Phosphorodithioate∗1Phosphorodithiolate∗2

Cadusafos, ethoprophos

R1O

P

NR2O

O Phosphoramidate Phenamiphos

R1O

P

NR2O

S O−R1 O−R2

Phosphoramidothioate∗1Phosphoramidothionate∗2

Isofenphos, propetamphos

R1O

P

NR2S

O O−R1 S−R2

Phosphoramidothioate∗1Phosphoramidothiolate∗2

Acephate, fosthiazate, methamidophos

R1O

P

CR2O

O Phosphonate Trichlorfon

R1O

P

CR2O

S O−R1 O−R2

Phosphonothioate∗1Phosphonothionate∗2

EPN

R1O

P

CR2S

S O−R1 S−R2

Phosphonodithioate∗1Phosphonothiolothionate∗2

Fonofos

∗1 ‘‘Thioate’’ does not distinguish between thionate (P=S) and thiolate (P−S−);∗2However, the terms ‘‘thionate,’’ ‘‘thiolate,’’ and ‘‘thiolothionate’’ for the groupings P(S)OR, P(O)SR, and P(S)SR are superseded by the O−R S−Rphosphorothioate and phosphorodithioate terminology.

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