Chemical classification Some pesticides have similar properties based on their chemical structure. Such chemicals belong to the same chemical class and frequently have similar toxicological modes of action. This page gives brief descriptions of the different chemical classes and provides representative chemical structures for most classes. Chemical Class Descriptions Representative Chemical Structures Insecticides Herbicides Microbiocides Fungicides Rodenticides About the Data: Accuracy, Currency, Comprehensiveness and Source Chemical Class Descriptions (alphabetical) Chemical Class Description 1,3-Indandione Rodenticides that act as anticoagulants. High acute toxicity. Indandione structure, with substituents. Representative chemical structure here. 2,6-Dinitroaniline Herbicidal compounds containing a dinitroaniline functional group. While these compounds are not acutely toxic to animals, many of them are possible human carcinogens. Representative chemical structure here. Alkyl phthalate Compounds derived from phthalic acid. Used as insecticides and insect repellents, as well as softeners in plastics manufacturing. Some of these compounds are suspected endocrine disruptors. Representative chemical structure here. Anilide Herbicidal compounds with an anilide functional group. These compounds have potential to leach into groundwater. Examples are propanil and flufenacet. Representative chemical structure here. Azole Fungicidal compounds, a few of which are carcinogenic. Representative chemical structures here. Benzimidazole Fungicidal compounds with a benzimidazole group. Benomyl and thiabendazole are examples. Representative chemical structure here. Benzoic acid Compounds with a benzoic acid functional group. Many of these are herbicides. Examples are chloramben and dicamba. Representative chemical structures here. Benzoyl urea Herbicidal compounds with a urea functional group having a benzoyl substituent. Frequently found as groundwater contaminants. Diflubenzuron and Triflumuron are examples. Representative chemical structure here. Bipyridilium Herbicides containing two pyridine rings, joined through a C-C bond. Most are acutely toxic to mammals. Paraquat is a bipyridilium compound. Representative chemical structures here. Bis-Carbamate Compounds containing two carbamate moieties. Typically herbicides. Representative chemical structure here. Botanical Pesticides derived from plants. These pesticides are typically a plant's natural defense against insects or fungi. Examples are nicotine and pyrethrins. Some of these compounds are quite toxic. Carboxamide Fungicidal compounds. Carboxin and flutolanil are examples. Representative chemical structure here. Chelating agent A compound that binds tightly to metal ions, generally increasing the water solubility of the ion. Chelation can also reduce the bioavailability of a metal ion by making it less reactive in biological systems. EDTA is the most widely used chelating agent in pesticide formulations. Chlorinated phenol Chlorinated aromatic alcohols typically used as microbiocides, fungicides, algaecides, or wood preservatives. Some of these compounds are carcinogenic and/or extremely toxic. Representative chemical structure here. Chloroacetanilide Herbicidal compounds with a chloroacetanilide functional group. These compounds are frequently found with their breakdown products as contaminants in groundwater. Examples are alachlor and metolachlor. Representative chemical structures here. Chlorophenoxy acid/ ester Herbicidal compounds such as 2,4-D and 2,4,5-T. Many chlorophenoxy compounds are suspected endocrine disruptors. Representative chemical structure here. Chloropyridinyl Triclopyr and its salts are members of this chemical class of herbicidal compounds.These compounds are commonly used on new-growth forests. Structure of the parent compound here. Coumarin Rodenticides that act as anticoagulants. Cinnamic acid lactone structure. Representative chemical structure here. Cyclohexenone A relatively new class of herbicidal compounds. While most have not been thoroughly evaluated, tralkoxydim has been rated as a Likely carcinogen by the U.S. EPA. Representative chemical structure here. Diacylhydrazine A relatively new class of insecticide that is persistent in the environment and may pose substantial ecological risks. Methoxyfenozide and tebufenozide are examples. There is some evidence these compounds may be endocrine disruptors. Representative chemical structure here. Dicarboximide Fungicidal compounds. Vinclozolin and iprodione are examples. Representative chemical structure here. Dinitrophenol Herbicidal and fungicidal compounds. Many are very acutely toxic, as well as being reproductive and developmental toxicants. Representative chemical structure here. Dithiocarbamate Typically fungicides with a carbamate structure where sulfurs replace both oxygens in the amide functional group. Examples are maneb, metam sodium, and ziram. These compounds are not cholinesterase inhibitors. Representative chemical structures here. Halogenated organic A diverse array of compounds composed mainly of carbon, hydrogen, and fluorine, chlorine, and/or bromine. Used as fumigants, fungicides, solvents and propellants. Imidazolinone A relatively new class of herbicidal compounds, with low acute toxicity to animals. Representative chemical structure here. Inorganic Any chemical compound not containing hydrocarbon moieties and not one of the toxic metals. Inorganic compounds of toxic metals--mercury, arsenic, cadmium, chromium, tin, lead, and silver--are listed separately (see below). Examples of inorganics are lime, phosphoric acid, and sulfuryl fluoride. Inorganic-Arsenic Arsenic-containing compounds that do not have arsenic-carbon bonds. These compounds are generally extremely toxic, causing acute toxicity, cancer, and developmental toxicity. Inorganic-Cadmium Cadmium-containing compounds that do not have cadmium-carbon bonds. These compounds are generally extremely toxic, causing acute toxicity, cancer, reproductive and developmental toxicity. Inorganic-Chromium (VI) Chromium-containing compounds that do not have chromium-carbon bonds, where the chromium atom is hexavalent (Cr+6). These compounds are extremely toxic, causing acute poisoning, cancer, reproductive and developmental toxicity. Inorganic-Lead Lead-containing compounds that do not have lead-carbon bonds. These compounds are extremely toxic, causing acute neurotoxicity, cancer, reproductive and developmental toxicity. Inorganic-Mercury Mercury-containing compounds that do not have mercury-carbon bonds. These compounds are generally extremely toxic, causing acute toxicity, cancer, and developmental toxicity. Inorganic-Silver Silver-containing compounds that do not have silver-carbon bonds. Most are used as microbiocides. Inorganic-Zinc Zinc-containing compounds that do not have zinc-carbon bonds. Most are used as microbiocides or fungicides. Microbial Pesticides composed of a particular species of microbe, e.g. Bacillus thuringiensis. Generally, these microbes produce a toxin that is the "active ingredient" that kills a pest. Microbial pesticides are typically very selective, affecting only the target pest. N-Methyl carbamate Compounds (mostly insecticides) with an N-methyl amide functional group. Most N-methyl carbamates are strong cholinesterase inhibitors which cause neurotoxicity in both insects and humans. N-methyl carbamates are the most acutely toxic of all carbamate pesticides. Representative chemical structure here. Naphthalene acetic acid Plant growth regulators with low acute toxicity. Representative chemical structures here. Oil - essential Oils with pesticidal properties extracted from plants. Examples are cinnamon, peppermint, jasmine, and lavender oils. Oil - vegetable Oils extracted from plants such as soybeans and corn and used as insecticides. They work by smothering the insects. Organoarsenic Arsenic-containing compounds with an organic moiety bound directly to arsenic. These compounds are generally extremely toxic, with many used as chemical warfare agents. Organochlorine Compounds, mostly insecticides, composed primarily of carbon, hydrogen, and chlorine. Organochlorines are typically very persistent in the environment and are known for bioaccumulating or building up in sediments, plants and animals. Many organochlorines are also suspected endocrine disruptors. Representative chemical structures here. Organomercury Mercury-containing compounds with an organic moiety bound directly to mercury. These compounds are generally extremely toxic, causing acute toxicity, cancer, and developmental toxicity. Organophosphorus Compounds, mostly insecticides, that contain a phosphorus atom bound to organic substituents, either alkyl or alkoxy groups. Most organo-phosphorus pesticides are cholinesterase inhibitors which cause neurotoxicity in both insects and humans. Representative chemical structures here. Organotin Tin-containing compounds with an organic moiety bound directly to tin. These compounds are generally extremely acutely toxic and are also known to be endocrine disruptors. Examples are tributyltin or triphenyltin salts. Other carbamate Compounds (mostly insecticides) with an amide functional group with substituents besides methyl groups. Many of these carbamates are mild cholinesterase inhibitors which cause neurotoxicity in both insects and humans. Representative chemical structure here. Petroleum derivative Compounds derived from crude oil through a distillation process. Frequently used as solvents, adjuvants, and insecticides. Depending on the level of refinement, petroleum derivatives often contain carcinogenic substances. Pheromone Insect sex-attractant hormones used to disrupt mating. These compounds are used in very small quantities and are very selective for a particular insect species. Their chemical structure is typically a long-chain alcohol, aldehyde or ester with at least one double bond. Representative chemical structures here. Cornell University hosts an excellent web site on pheromones. Phosphonoglycine Herbicidal organophosphorus compound. These compounds inhibit a plant-specific enzyme and have low acute toxicity to mammals. Glyphosate and its salts and esters (active ingredients in Roundup products) belong to this class of compounds. Representative structure here. Pyrazole A relatively new class of insecticide that is persistent in the environment and may pose substantial ecological risks. Chlorfenapyr (Pirate) is an example. Representative chemical structure here. Pyrethroid Synthetic insecticides (typically cyclopropane carboxylates) structurally similar to pyrethrins, which are naturally occurring insecticidal compounds. Many pyrethroids are suspected endocrine disruptors. Representative chemical structures here. Pyridinecarboxylic acid Herbicidal compounds with low acute toxicity. Representative chemical structure here. Quaternary ammonium Ammonium salts with four alkyl or aryl groups, typically used as microbiocides or algaecides. Representative chemical structure here. Silicone Synthetic oils with a silicon-oxygen backbone. Used as antifoaming agents and emulsifiers. Soap Compounds with surfactant or detergent properties. Used as insecticides and adjuvants. Substituted benzene Fungicidal compounds with a benzene ring substituted with various substituents. Some of these compounds are very toxic wood preservatives such as pentachloro-nitrobenzene (PCNB) and hexachlorobenzene. Representative chemical structure here. Sulfonyl urea Herbicidal compounds with a urea functional group having a sulfonyl substituent. Frequently found as groundwater contaminants. Bensulfuron-methyl and rimsulfuron are examples. Representative chemical structure here. Thiocarbamate Typically herbicides with a carbamate structure where sulfur replaces one of the oxygens in the amide functional group. Examples are cycloate, butylate, and molinate. These compounds are weak cholinesterase inhibitors. Representative chemical structure here. Triazine Typically herbicides or microbiocides containing a triazine ring. Frequently found in groundwater, along with their transformation products. Representative chemical structure here. Uracil Herbicidal compounds derived from uracil. Frequently found as groundwater contaminants. Bromacil and terbacil are examples. Representative chemical structure here. Urea Herbicidal compounds with a urea functional group. Frequently found as groundwater contaminants. Diuron and linuron are examples. Some of these compounds are carcinogenic. Representative chemical structures here.   Coming soon Fungicides: Mercaptobenzothiazole Pyrimidine Substituted Benzene Thiophthalimide Strobin Herbicides: Amide Phosphinico amino acid Microbiocides/Wood Preservatives (mostly): Alkyl Amino Propane Chlorinated Phenol Hydantoin Isothiazolone Phenol Quaternary Ammonium Compounds Oils, soaps, solvents, adjuvants: Alcohol/Ether Polyalkoxy Compound Other: Carbohydrate Cellulose derivative Representative Chemical Structures Insecticides Alkyl Phthalates Chloronicotinyl Compounds Diacylhydrazines N-Methyl Carbamates Organochlorine Compounds Organophosphorus Compounds Other Carbamates Pheromones Pyrazoles Pyrethroids Herbicides 2,6-Dinitroanilines Anilides Aryoxyphenoxy proprionic acids Benzoic Acids Benzoyl Ureas Bipyridilium Compounds Bis-Carbamates Chloroacetanilide Chlorophenoxy Acids/Esters Chloropyridinyls Cyclohexenones Dinitrophenols Imidazolinones Naphthalene Acetic Acid Derivatives Phosphonoglycines Pyridinecarboxylic Acids Sulfonyl Ureas Thiocarbamates Triazines Ureas Uracils Microbiocides Chlorinated Phenols Hydantoins Isothiazolones Phenols Quaternary Ammonium Compounds Fungicides Azoles Benzimidazoles Carboxamides Dicarboximides Dithiocarbamates Substituted Benzenes Rodenticides Coumarins 1,3-Indandiones Alkyl Phthalates Top of page              Back to Structures Index Chloronicotinyl Compounds Top of page              Back to Structures Index Diacylhydrazines Top of page              Back to Structures Index N-Methyl Carbamates Top of page              Back to Structures Index Organochlorine Compounds Organochlorine compounds do not have a common chemical structure, but all of them have multiple carbon-chlorine bonds.   Top of page              Back to Structures Index Organophosphorus Compounds The general chemical structures associated with organophosphorus pesticides are: Top of page              Back to Structures Index   Other Carbamates Top of page              Back to Structures Index Pheromones Many pheromones have a long-chain alkyl component with one or more double bonds and a terminal alcohol, ester, or aldehyde functional group. Others are more variable in structure. Some examples are shown below. Top of page              Back to Structures Index Pyrazoles   Top of page              Back to Structures Index Pyrethroids Top of page              Back to Structures Index     2,6-Dinitroanilines Top of page              Back to Structures Index Anilides   Top of page              Back to Structures Index Aryloxyphenoxy proprionic acids Top of page              Back to Structures Index Benzoic Acids Top of page              Back to Structures Index Benzoyl Ureas Top of page              Back to Structures Index Bipyridilium Compounds Top of page              Back to Structures Index Bis-Carbamates Top of page              Back to Structures Index Chlorophenoxy Acids/Esters Top of page              Back to Structures Index Chloroacetanilide Top of page              Back to Structures Index Chloropyridinyl Top of page              Back to Structures Index Cyclohexenones   Top of page              Back to Structures Index Dinitrophenols   Top of page              Back to Structures Index Imidazolinone   Top of page              Back to Structures Index Naphthalene Acetic Acid Derivatives   Top of page              Back to Structures Index Phosphonoglycines   Top of page              Back to Structures Index   Pyridinecarboxylic Acids  Top of page              Back to Structures Index Sulfonyl Ureas Top of page              Back to Structures Index Thiocarbamates Top of page              Back to Structures Index Triazines Top of page              Back to Structures Index Ureas The general structure is a urea unit with substituents: Some specific examples are diuron and tebuthiuron. Top of page              Back to Structures Index Uracils Top of page              Back to Structures Index Chlorinated Phenols Top of page              Back to Structures Index Quaternary Ammonium Salts Top of page              Back to Structures Index Azoles Top of page              Back to Structures Index Benzimidazoles Top of page              Back to Structures Index Carboxamides Top of page              Back to Structures Index Dicarboximides Top of page              Back to Structures Index Dithiocarbamates Top of page              Back to Structures Index Substituted Benzenes Top of page              Back to Structures Index Coumarins Top of page              Back to Structures Index 1,3-Indandiones Top of page              Back to Structures Index About the Data: Accuracy, currency, comprehensiveness and source This dataset is maintained by PAN staff by evaluation of chemical structure, and research using the references listed below. Last updated December 11, 2003. PAN staff will continue to add to this list and update it at least annually. References: Chem Finder, CambridgeSoft Corporation. Viewed on April 8, 2005. The Pesticide Manual, 11th edition, C. D. S. Tomlin, Ed., British Crop Protection Council (Farnham, Surrey, UK, 1997). Merck Index, 12th edition, Merck Publishing Group (Rahway, NJ, 1996). A. Wood, Compendium of Pesticide Common Names, Copyright © 1995-2003. Viewed on April 8, 2005. Top of page Last updated April 7, 2005 .