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Encyclopedia > IUPAC nomenclature of organic chemistry

The IUPAC nomenclature of organic chemistry is a systematic method of naming organic chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC). Ideally, every organic compound should have a name from which an unambiguous structural formula can be drawn. There is also an IUPAC nomenclature of inorganic chemistry. See also phanes nomenclature of highly complex cyclic molecules. There are millions of possible objects that can be described in science, too many to create common names for every one. ... Benzene is the simplest of the arenes, a family of organic compounds An organic compound is any member of a large class of chemical compounds whose molecules contain carbon and hydrogen; therefore, carbides, carbonates, carbon oxides and elementary carbon are not organic (see below for more on the definition controversy... IUPAC logo The International Union of Pure and Applied Chemistry (IUPAC) (Pronounced as eye-you-pack) is an international non-governmental organization established in 1919 devoted to the advancement of chemistry. ... A chemical compound is a chemical substance of two or more different chemically bonded chemical elements, with a fixed ratio determining the composition. ... The structural formula of a chemical compound is a graphical representation of the molecular structure showing how the atoms are arranged. ... The IUPAC nomenclature of inorganic chemistry is a systematic method of naming inorganic chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC). ... Phanes are sub-structures of highly complex organic molecules introduced for simplification of the naming of these highly complex molecules. ...


For ordinary communication, to spare a tedious description, the official IUPAC naming recommendations are not always followed in practice except when it is necessary to give a concise definition to a compound, or when the IUPAC name is simpler (viz. ethanol against ethyl alcohol). Otherwise the common or trivial name may be used, often derived from the source of the compound (See Sec 14. below) In chemistry, a trivial name (also common or vernacular name) is a non-systematic name. ...

Contents

Basic principles

In IUPAC nomenclature, a number of prefixes, suffixes and infixes are used to describe the type and position of functional groups in the compound. In linguistics, a prefix is a type of affix that precedes the morphemes to which it can attach. ... Look up affix in Wiktionary, the free dictionary. ... This article or section does not cite its references or sources. ... In organic chemistry, functional groups are specific groups of atoms within molecules, that are responsible for the characteristic chemical reactions of those molecules. ...


For many compounds, naming can begin by determining the name of the parent hydrocarbon and by identifying any functional groups in the molecule that distinguish it from the parent hydrocarbon. The numbering of the parent alkane is used, as modified, if necessary, by application of the Cahn Ingold Prelog priority rules ("CIP") in the case that ambiguity remains after consideration of the structure of the parent hydrocarbon alone. The name of the parent hydrocarbon is modified by the application of the highest-priority functional group suffix, with the remaining functional groups indicated by numbered prefixes, appearing in the name in alphabetical order from first to last. Oil refineries are key to obtaining hydrocarbons; crude oil is processed through several stages to form desirable hydrocarbons, used in fuel and other commercial products. ... In organic chemistry, functional groups are specific groups of atoms within molecules, that are responsible for the characteristic chemical reactions of those molecules. ... Chemical structure of methane, the simplest alkane Alkanes are chemical compounds that consists only of the elements carbon (C) and hydrogen (H) (i. ... For compounds found in organic chemistry, the Cahn Ingold Prelog priority rules are used to determine the orientation of a molecule for purposes of assigning stereochemistry at a stereocenter and for assigning the name of isomers of molecules possessing double bonds such as alkenes. ...


In many cases, lack of rigor in applying all such nomenclature rules still yields a name that is intelligible — the aim, of course, being to avoid any ambiguity in terms of what substance is being discussed. For the medical term see rigor (medicine) Rigour (American English: rigor) has a number of meanings in relation to intellectual life and discourse. ...


For instance, strict application of CIP priority to the naming of the compound

NH2CH2CH2OH

would render the name as 2-aminoethanol, which is preferred. However, the name 2-hydroxyethanamine unambiguously refers to the same compound.


How the name was constructed:

  1. There are two carbons in the main chain; this gives the root name "eth".
  2. Since the carbons are singly-bonded, the suffix begins with "an".
  3. The two functional groups are an alcohol (OH) and an amine (NH2). The alcohol has the higher atomic number, and takes priority over the amine. The suffix for an alcohol ends in "ol", so that the suffix is "anol".
  4. The amine group is not on the carbon with the OH (the #1 carbon), but one carbon over (the #2 carbon); therefore we indicate its presence with the prefix "2-amino".
  5. Putting together the prefix, the root and the suffix, we get "2-aminoethanol".

There is also an older naming system for organic compounds known as common nomenclature, which is often used for simple, well-known compounds, and also for complex compounds whose IUPAC names are too complex for everyday use. It has been suggested that List of elements by atomic number be merged into this article or section. ...


Simplified molecular input line entry specification (SMILES) strings are commonly used to describe organic compounds, and as such are a form of 'naming' them. The simplified molecular input line entry specification or SMILES is a specification for unambiguously describing the structure of chemical molecules using short ASCII strings. ...


Alkanes

Main article: Alkanes

Straight-chain alkanes take the suffix "-ane" and are prefixed depending on the number of carbon atoms in the chain, following standard IUPAC numerical multiplier rules. The first few are: An alkane in organic chemistry is a type of hydrocarbon in which the molecule has the maximum possible number of hydrogen atoms and so has no double bonds (they are saturated). ... The numerical multiplier (or multiplying affix) in IUPAC nomenclature indicates how many particular atoms or functional groups are attached at a particular point in a molecule. ...

Number of carbons 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 20 30
Prefix Meth Eth Prop But Pent Hex Hept Oct Non Dec Undec Dodec Tridec Tetradec Pentadec Eicos Triacont

For example, the simplest alkane is CH4 methane, and the nine-carbon alkane CH3(CH2)7CH3 is named nonane. If one was to name the 157-carbon alkane CH3(CH2)155CH3 the name would be heptapentahectane.


Cyclic alkanes are simply prefixed with "cyclo-", for example C4H8 is cyclobutane and C6H12 is cyclohexane.

Iupac-alkane-1.png

Branched alkanes are named as a straight-chain alkane with attached alkyl groups. They are prefixed with a number indicating the carbon the group is attached to, counting from the end of the alkane chain. Infixed is the name of the substituent, as for alkanes in the table above, plus "-yl". For example, (CH3)2CHCH3, commonly known as isobutane, is treated as a propane chain with a methyl group bonded to the middle (2) carbon, and given the systematic name 2-methylpropane. Numbers may be dropped when there is no ambiguity, so 2-methylpropane is just methylpropane. (1-methylpropane would be identical to butane.) IUPAC naming (alkane); File links The following pages link to this file: User:DrBob/Figures IUPAC nomenclature Categories: GFDL images ... IUPAC naming (alkane); File links The following pages link to this file: User:DrBob/Figures IUPAC nomenclature Categories: GFDL images ... An alkyl is a univalent radical containing only carbon and hydrogen atoms arranged in a chain. ...


If there is ambiguity in the position of the substituent, depending on which end of the alkane chain is counted as "1", then numbering is chosen so that the smallest number is used. For example, (CH3)2CHCH2CH3 (isopentane) is named 2-methylbutane, not 3-methylbutane. Since this resolves the ambiguity, the number is again dropped in this case.

If there are multiple side-branches of the same size alkyl group, their positions are separated by commas and the group prefixed with di-, tri-, tetra-, etc., depending on the number of branches (e.g. C(CH3)4 2,2-dimethylpropane). If there are different groups, they are added in alphabetical order, separated by commas or hyphens: 3-ethyl-4-methylhexane. The longest possible main alkane chain is used; therefore 3-ethyl-4-methylhexane instead of 2,3-diethylpentane, even though these describe equivalent structures. The di-, tri- etc. prefixes are ignored for the purpose of alphabetical ordering of side chains (e.g. 3-ethyl-2,4-dimethylpentane, not 2,4-dimethyl-3-ethylpentane). If multiple chains of the longest possible length exist, the chain that has a larger number of branch points is the chain that is used. IUPAC naming (alkane); File links The following pages link to this file: User:DrBob/Figures IUPAC nomenclature Categories: GFDL images ... The term Side chain can have different meanings depending on the context: In chemistry and biochemistry a side chain is a part of a molecule attached to a core structure. ...

Iupac-alkane-4.png

Subsidiary branches off a side-chain are prefixed according to a secondary numbering system specific to that side branch, numbering from the point of attachment to the main chain, and then the whole side-branch is parenthesised and treated as a single substituent. For example, 4-(1-methylethyl)octane is an octane chain with a side chain bonded to the 4th carbon, the side chain consisting of an ethyl group with a methyl group attached to the carbon closest to the main chain.
IUPAC naming (alkane); File links The following pages link to this file: User:DrBob/Figures IUPAC nomenclature Categories: GFDL images ...


Alkenes and Alkynes

Main articles: Alkenes and Alkynes

Alkenes are named for their parent alkane chain with the suffix "-ene" and an infixed number indicating the position of the double-bonded carbon in the chain: CH2=CHCH2CH3 is but-1-ene. Ethene (ethylene) and propene (propylene) do not require infixed numbers, since there is no ambiguity in the structures. As before, the lowest number is used. An alkene is one of the three classes of unsaturated hydrocarbons that contain at least one carbon-carbon double bond and have the general molecular formula of CnH2n (the other two being alkynes and arenes). ... Alkynes are hydrocarbons that have at least one triple bond between carbon atoms. ... IUPAC naming (alkene); File links The following pages link to this file: User:DrBob/Figures IUPAC nomenclature Categories: GFDL images ... Ethylene (or IUPAC name ethene) is the chemical compound with the formula C2H4. ... Propylene, also known by its IUPAC name propene, is an organic compound having the chemical formula C3H6. ...


Multiple double bonds take the form -diene, -triene, etc., with the size prefix of the chain taking an extra "a": CH2=CHCH=CH2 is buta-1,3-diene. Simple cis and trans isomers are indicated with a prefixed cis- or trans-: cis-but-2-ene, trans-but-2-ene. More complex geometric isomerisations are described using the Cahn Ingold Prelog priority rules. CIS usually refers to: Commonwealth of Independent States, a modern-day political entity consisting of 11 former Soviet Union Republics CIS is also an acronym for: Canadian Interuniversity Sport Cancer Information Service Carcinoma in situ Centre for Independent Studies Center for Immigration Studies Chinese International School Cisalpino Citizenship & Immigration Services... Trans is a Latin noun or prefix, meaning across, beyond or on the opposite side [of] . It is the opposite of cis, which means on the same side [of]. In chemistry, a double bond (or ring) not subject to free rotation in which the greater radical on both ends is... Cis-2-butene Trans-2-butene In chemistry, geometric isomerism or cis-trans isomerism is a form of stereoisomerism and describes the orientation of functional groups within the molecule. ... For compounds found in organic chemistry, the Cahn Ingold Prelog priority rules are used to determine the orientation of a molecule for purposes of assigning stereochemistry at a stereocenter and for assigning the name of isomers of molecules possessing double bonds such as alkenes. ...

Alkynes are named using the same system, with the suffix "-yne" indicating a triple bond: ethyne (acetylene), propyne (methylacetylene).
IUPAC naming (alkyne); File links The following pages link to this file: User:DrBob/Figures IUPAC nomenclature Categories: GFDL images ... Acetylene (systematic name: ethyne) is the simplest alkyne hydrocarbon, consisting of two hydrogen atoms and two carbon atoms connected by a triple bond. ... Methylacetylene (propyne) is an alkyne with the chemical formula CH3C≡CH. It is a component of MAPP gas, which is commonly used in gas welding. ...


Alcohols

Main article: Alcohols

Alcohols (R-OH) drop the terminal "e" from the name of the parent alkane, and take the suffix "-ol" with an infix numerical bonding position: CH3CH2CH2OH is propan-1-ol. (Methanol and ethanol are unambiguous and do not require position numbers). The suffixes -diol, -triol, -tetraol, etc., are used for multiple -OH groups: Ethylene glycol CH2OHCH2OH is ethane-1,2-diol. In general usage, alcohol (from Arabic al-khwl الكحول, or al-ghawl الغول) refers almost always to ethanol, also known as grain alcohol, and often to any beverage that contains ethanol (see alcoholic beverage). ... IUPAC naming (alcohol); File links The following pages link to this file: User:DrBob/Figures IUPAC nomenclature Categories: GFDL images ... Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naptha or wood spirits, is a chemical compound with chemical formula CH3OH. It is the simplest alcohol, and is a light, volatile, colourless, flammable, poisonous liquid with a distinctive odor that is somewhat milder and sweeter than ethanol (ethyl alcohol). ... Grain alcohol redirects here. ... Ethylene glycol (monoethylene glycol (MEG), IUPAC name: ethane-1,2-diol) is an alcohol with two -OH groups (a diol), a chemical compound widely used as an automotive antifreeze. ...

If higher precedence functional groups are present (see order of precedence, below), the prefix "hydroxy" is used with the bonding position: CH3CHOHCOOH is 2-hydroxypropanoic acid.
IUPAC naming (alcohol); File links The following pages link to this file: User:DrBob/Figures IUPAC nomenclature Categories: GFDL images ...


Halogens (Alkyl Halides)

Main article: Halogens

Halogen functional groups are prefixed with the bonding position and take the form fluoro-, chloro-, bromo-, iodo-, etc., depending on the halogen. Multiple groups are dichloro-, trichloro-, etc, and dissimilar groups are orded alphabetically as before. For example, CHCl3 (chloroform) is trichloromethane. The anesthetic Halothane (CF3CHBrCl) is 2-bromo-2-chloro-1,1,1-trifluoroethane.
The halogens are a chemical series. ... IUPAC naming (haloalkane); File links The following pages link to this file: User:DrBob/Figures IUPAC nomenclature Categories: GFDL images ... The halogens or halogen elements are a series of nonmetal elements from Group 17 (old-style: VII or VIIA; Group 7 IUPAC Style) of the periodic table, comprising fluorine, F, chlorine, Cl, bromine, Br, iodine, I, and astatine, At. ... For the song Chloroform by Spoon, see A Series of Sneaks Chloroform, also known as trichloromethane and methyl trichloride, is a chemical compound with formula CHCl3. ... Halothane vapour is an inhalational general anaesthetic. ...


Ketones

Main article: Ketones

In general ketones (R-CO-R) take the suffix "-one" (pronounced own, not won) with an infix position number: CH3CH2CH2COCH3 is pentan-2-one. For common ketones some traditional names such as acetone and benzophenone predominate, and these are acceptable IUPAC names, although some introductory chemistry texts use alternative names for acetone such as propan-2-one or propanone (see diagram). Additionally, in such unambigous cases as propanone, the infixed number can be dropped. If a higher precedence suffix is in use, the prefix "oxo-" is used: CH3CH2CH2COCH2CHO is 3-oxohexanal.
A ketone is either the functional group characterized by a carbonyl group linked to two other carbon atoms or a compound that contains this functional group. ... IUPAC naming (ketone); File links The following pages link to this file: User:DrBob/Figures IUPAC nomenclature Categories: GFDL images ... The chemical compound acetone (also known as propanone, dimethyl ketone, 2-propanone, propan-2-one and β-ketopropane) is the simplest representative of the ketones. ... Benzophenone, also known as diphenylmethanone, phenyl ketone, diphenyl ketone, or benzoylbenzene. ...


Aldehydes

Main article: Aldehydes

Aldehydes (R-CHO) take the suffix "-al". Since they are always at the end of an alkane chain, they do not need a position number: HCHO (formaldehyde) is methanal, CH3CHO (acetaldehyde) is ethanal. If other functional groups are present, the chain is numbered such that the aldehyde carbon is in the "1" position. An aldehyde is either a functional group consisting of a terminal carbonyl group, or a compound containing a terminal carbonyl group. ... IUPAC naming (aldehyde); File links The following pages link to this file: User:DrBob/Figures IUPAC nomenclature Categories: GFDL images ... The chemical compound formaldehyde (also known as methanal) is a gas with a pungent smell. ... R-phrases , , S-phrases , , , Flash point −39 °C Autoignition temperature 185 °C RTECS number AB1925000 Supplementary data page Structure and properties n, εr, etc. ...


If a prefix form is required, "oxo-" is used (as for ketones), with the position number indicating the end of a chain: CHOCH2COOH is 3-oxopropanoic acid. If the carbon in the carbonyl group cannot be included in the attached chain (for instance in the case of cyclic aldehydes), the prefix "formyl-" or the suffix "-carbaldehyde" is used: C6H11CHO is cyclohexanecarbaldehyde.
Cyclic aldehydes have their -CHO group bonded directly to the ring. ...


Carboxylic acids

Main article: Carboxylic acids

In general carboxylic acids are named with the suffix -oic acid (etymologically a back-formation from benzoic acid). As for aldehydes, they take the "1" position on the parent chain, but do not have their position number indicated. For example, CH3CH2CH2CH2COOH (valeric acid) is named pentanoic acid. For common carboxylic acids some traditional names such as acetic acid are in such widespread use they are considered retained IUPAC names, although "systematic" names such as ethanoic acid are also acceptable. For carboxylic acids attached to a benzene ring such as Ph-COOH, these are named as benzoic acid or its derivatives. In chemistry, carboxylic acids (also called alkanoic acids) are organic acids characterized by the presence of a carboxyl group. ... IUPAC naming (carboxylic acid); File links The following pages link to this file: User:DrBob/Figures IUPAC nomenclature Categories: GFDL images ... In etymology, the process of back-formation is the creation of a neologism by reinterpreting an earlier word as a compound and removing the spuriously supposed affixes. ... Benzoic acid, C7H6O2 (or C6H5COOH), is a colorless crystalline solid and the simplest aromatic carboxylic acid. ... Acetic acid, also known as ethanoic acid, is an organic chemical compound best recognized for giving vinegar its sour taste and pungent smell. ... In chemistry, the phenyl group or phenyl ring (often abbreviated as -Ph) is the functional group with the formula -C6H5 Picture where the six carbon atoms are arranged in a cyclic manner. ...


If there are multiple carboxyl groups on the same parent chain, the suffix "-carboxylic acid" can be used (as -dicarboxylic acid, -tricarboxylic acid, etc.). In these cases, the carbon in the carboxyl group does not count as being part of the main alkane chain. The same is true for the prefix form, "carboxyl-". Citric acid is one example; it is named 2-hydroxypropane- 1,2,3-tricarboxylic acid, rather than 2-carboxy, 2-hydroxypentanedioic acid.
A carboxyl or carboxylic group is a functional group consisting of a carbon atom and an oxygen atom doubly bonded to each other. ... Citric acid is a weak organic acid found in citrus fruits. ...


Ethers

Main article: Ethers

Ethers (R-O-R) consist of an oxygen atom between the two attached carbon chains. The shorter of the two chains becomes the first part of the name with the -ane suffix changed to -oxy, and the longer alkane chain become the suffix of the name of the ether. Thus CH3OCH3 is methoxymethane, and CH3OCH2CH3 is methoxyethane (not ethoxymethane). If the oxygen is not attached to the end of the main alkane chain, then the whole shorter alkyl-plus-ether group is treated as a side-chain and prefixed with its bonding position on the main chain. Thus CH3OCH(CH3)2 is 2-methoxypropane.
Ethers can refer to: In internet routing, the term associated with hosts In Organic chemistry, the plural of ether This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... IUPAC naming (ether); File links The following pages link to this file: User:DrBob/Figures IUPAC nomenclature Categories: GFDL images ... Methoxyethane, also known as methyl ethyl ether, is a colorless gaseous ether with a medicine-like odor. ...


Esters

Main article: Esters

Esters (R-CO-O-R') are named as alkyl derivatives of carboxylic acids. The alkyl (R') group is named first. The R-CO-O part is then named as a separate word based on the carboxylic acid name, with the ending changed from -oic acid to -oate. For example, CH3CH2CH2CH2COOCH3 is methyl pentanoate, and (CH3)2CHCH2CH2COOCH2CH3 is ethyl 4-methylpentanoate. For esters such as ethyl acetate (CH3COOCH2CH3), ethyl formate (HCOOCH2CH3) or dimethyl phthalate that are based on common acids, IUPAC recommends use of these established names, called retained names. The -oate changes to -ate. Some simple examples, named both ways, are shown in the figure above. For the Biblical Ester, see Esther. ... IUPAC naming (ester); File links The following pages link to this file: User:DrBob/Figures IUPAC nomenclature Categories: GFDL images ... Ethyl acetate is the organic compound with the formula CH3CH2OC(O)CH3. ... Ethyl formate, also known as ethyl methanoate is an ester formed when ethanol reacts with formic acid. ...

If the alkyl group is not attached at the end of the chain, the bond position to the ester group is infixed before "-yl": CH3CH2CH(CH3)OOCCH2CH3 may be called but-2-yl propanoate or but-2-yl propionate.
IUPAC naming (ester); File links The following pages link to this file: User:DrBob/Figures IUPAC nomenclature Categories: GFDL images ...


Amines and Amides

Main articles: Amines and Amides

Amines (R-NH2) are named for the attached alkane chain with the suffix "-amine" (e.g. CH3NH2 methanamine). If necessary, the bonding position is infixed: CH3CH2CH2NH2 propan-1-amine, CH3CHNH2CH3 propan-2-amine. The prefix form is "amino-". Ammonia Amines are organic compounds containing nitrogen as the key atom in the amine functional group. ... In chemistry, the term amide has several meanings. ... IUPAC naming (amines); File links The following pages link to this file: User:DrBob/Figures IUPAC nomenclature Categories: GFDL images ...


For secondary amines (of the form R-NH-R), the longest carbon chain attached to the nitrogen atom becomes the primary name of the amine; the other chain is prefixed as an alkyl group with location prefix given as an italic N: CH3NHCH2CH3 is N-methylethanamine. Tertiary amines (R-NR-R) are treated similarly: CH3CH2N(CH3)CH2CH2CH3 is N-methyl-N-ethylpropanamine.

Amides (R-CO-NH2) take the suffix "-amide". There is no prefix form, and no location number is required since they always terminate a carbon chain, e.g. CH3CONH2 (acetamide) is named ethanamide. IUPAC naming (amides); File links The following pages link to this file: User:DrBob/Figures IUPAC nomenclature Categories: GFDL images ... acetamide Acetamide (or Acetic acid amide or Ацетамид) CH3CONH2, the amide of acetic acid, is a white crystalline solid in pure form. ...


Secondary and tertiary amides are treated similarly to the case of amines: alkane chains bonded to the nitrogen atom are treated as substituents with the location prefix N: HCON(CH3)2 is N,N-dimethylmethanamide.


Cyclic compounds

Cycloalkanes and aromatic compounds can be treated as the main parent chain of the compound, in which case the position of substituents are numbered around the ring structure. For example, the three isomers of xylene CH3C6H4CH3, commonly the ortho-, meta-, and para- forms, are 1,2-dimethylbenzene, 1,3-dimethylbenzene, and 1,4-dimethylbenzene. The cyclic structures can also be treated as functional groups themselves, in which case they take the prefix "cycloalkyl-" (e.g. "cyclohexyl-") or for benzene, "phenyl-". IUPAC naming (cyclics); File links The following pages link to this file: User:DrBob/Figures Xylene IUPAC nomenclature Categories: GFDL images ... cyclobutane Cycloalkanes (also called naphthenes) are chemical compounds with one or more carbon rings to which hydrogen atoms are attached according to the formula CnH2n. ... In chemistry, an aromatic molecule is one in which electrons are free to cycle around circular arrangements of atoms, which are alternately singly and doubly bonded to one another. ... The term xylenes refers to a group of 3 benzene derivatives which encompasses ortho-, meta-, and para- isomers of dimethyl benzene. ...


The IUPAC nomenclature scheme becomes rapidly more elaborate for more complex cyclic structures, with notation for compounds containing conjoined rings, and many common names such as phenol, furan, indole, etc. being accepted as base names for compounds derived from them.
Phenol, also known under an older name of carbolic acid, is a colourless crystalline solid with a typical sweet tarry odor. ... Furan, also known as furane and furfuran, is a heterocyclic organic compound, produced when wood, especially pine-wood, is distilled. ... Indole is an aromatic heterocyclic organic compound. ...


Order of precedence of groups

When compounds contain more than one functional group, the order of precedence determines which groups are named with prefix or suffix forms. The highest precedence group takes the suffix, with all others taking the prefix form. However, double and triple bonds only take suffix form (-en and -yn) and are used with other suffixes.


Prefixed substituents are ordered alphabetically (excluding any modifiers such as di-, tri-, etc.), e.g. chlorofluoromethane, not fluorochloromethane. If there are multiple functional groups of the same type, either prefixed or suffixed, the position numbers are ordered numerically (thus ethane-1,2-diol, not ethane-2,1-diol.) The N position indicator for amines and amides comes before "1", e.g. CH3CH(CH3)CH2NH(CH3) is N,2-dimethylpropanamine.

Priority Functional group Formula Prefix Suffix
1 Cations
   e.g. Ammonium
 
–NH4+
-onio-
ammonio-
-onium
-ammonium
2 Carboxylic acids
   Thiocarboxylic acids
   Selenocarboxylic acids
   Sulfonic acids
   Sulfinic acids
   Sulfenic acids
–COOH
–COSH
–COSeH
–SO3H
–SO2H
–SOH
carboxy-
thiocarboxy-
selenocarboxy-
sulfo-
sulfino-
sulfeno-
-oic acid*
-thioic acid*
-selenoic acid*
-sulfonic acid
-sulfinic acid
-sulfenic acid
3 Carboxylic acid derivatives
   Esters
   Acyl chlorides
   Amides
   Imides
   Amidines
 
–COOR
–COCl
–CONH2
–CON=C<
–C(=NH)NH2
 
R-oxycarbonyl-
chloroformyl-
carbamoyl-
-imido-
amidino-
 
 
-oyl chloride*
-amide*
-imide*
-amidine*
4 Nitriles
   Isocyanides
–CN
–NC
cyano-
isocyano-
-nitrile*
isocyanide
5 Aldehydes
   Thioaldehydes
–CHO
–CHS
formyl-
thioformyl-
-al*
-thial*
6 Ketones
   Thioketones
>CO
>CS
oxo-
thiono-
-one
-thione
7 Alcohols
   Thiols
   Selenols
   Tellurols
–OH
–SH
–SeH
–TeH
hydroxy-
sulfanyl-
selanyl-
tellanyl-
-ol
-thiol
-selenol
-tellurol
8 Hydroperoxides –OOH hydroperoxy- -hydroperoxide
9 Amines
   Imines
   Hydrazines
–NH2
=NH
–NHNH2
amino-
imino-
hydrazino-
-amine
-imine
-hydrazine
10 Ethers
   Thioethers
   Selenoethers
–O–
–S–
–Se–
-oxy-
-thio-
-seleno-
 
11 Peroxides
   Disulfides
–OO–
–SS–
-peroxy-
-disulfanyl-
 

*Note: These suffixes, in which the carbon atom is counted as part of the preceding chain, are the most commonly used. See individual functional group articles for more details. In organic chemistry, functional groups are specific groups of atoms within molecules, that are responsible for the characteristic chemical reactions of those molecules. ... This article or section does not cite any references or sources. ... A cation is an ion with positive charge. ... A ball-and-stick model of the ammonium cation Fumes from hydrochloric acid and ammonia forming a white cloud of ammonium chloride Ammonium is also an old name for the Siwa Oasis in western Egypt. ... Structure of a carboxylic acid The 3D structure of the carboxyl group A space-filling model of the carboxyl group Carboxylic acids are organic acids characterized by the presence of a carboxyl group, which has the formula -C(=O)OH, usually written -COOH or -CO2H. [1] Carboxylic acids are Bronsted... It has been suggested that Sulfonic acid/Temp be merged into this article or section. ... The general structure of a sulfinic acid Sulfinic acids are oxoacids of sulfur with the structure RSO(OH). ... The general structure of a sulfenic acid A sulfenic acid is a sulfur compound and oxoacid with the general formula RSOH, where R ≠ H. Sulfenic acids are generally unstable. ... A carboxylic acid ester. ... General Chemical Structure of an Acyl Chloride In organic chemistry, an acyl chloride (or acid chloride) is an organic compound which is a reactive derivative of a carboxylic acid. ... Amide functional group Amides possess a conjugated system spread over the O, C and N atoms, consisting of molecular orbitals occupied by delocalized electrons. ... In organic chemistry, imide is a functional group consisting of two carboxylic acid groups (or one dicarboxylic acid) bound to a primary amine or ammonia. ... An amidine is a functional group or type of chemical compound that has two amine groups attached to the same carbon atom with one carbon-nitrogen double bond,exactly its derivate of acid,when suspended the double bond is protonized: HN=CR-NH2. ... A nitrile is any organic compound which has a -C≡N functional group. ... An isocyanide (erroneously called isonitrile) is a functional group in organic synthesis containing carbon and nitrogen. ... An aldehyde. ... A thial is a functional group in organic chemistry which is similar to an aldehyde (R-COH) in which a sulfur (S) atom replaces the oxygen (O) atom of aldehyde. ... Ketone group A ketone(key tone) is either the functional group characterized by a carbonyl group (O=C) linked to two other carbon atoms or a chemical compound that contains this functional group. ... Thioketones are organic compounds that are the sulfur-containing analogues of ketones. ... Functional group of an alcohol molecule. ... Sulphydryl // In organic chemistry, a thiol is a compound that contains the functional group composed of a sulfur atom and a hydrogen atom (-SH). ... In organic chemistry, a selenol is a compound that contains the functional group composed of a selenium atom bonded to a hydrogen atom (-SeH). ... Organic peroxides are organic molecules containing the peroxide functional group ROOR If the R is hydrogen, the compound is called organic hydroperoxide. ... The general structure of an amine Amines are organic compounds and a type of functional group that contain nitrogen as the key atom. ... An imine is a functional group or chemical compound containing a carbon-nitrogen double bond. ... Hydrazine is the chemical compound with formula N2H4. ... Ether is the general name for a class of chemical compounds which contain an ether group — an oxygen atom connected to two (substituted) alkyl groups. ... A thioether (similar to sulfide) is a functional group in organic chemistry that has the structure R1-S-R2 as shown on right. ... A peroxide is a compound containing an oxygen-oxygen single bond. ... In chemistry, a disulfide is an ion formed by sulfur atoms. ...


Common nomenclature - trivial names

Common nomenclature is an older system of naming organic compounds. Instead of using the prefixes for the carbon skeleton above, another system is used. The pattern can be seen below.

Number of carbons Prefix as in new system Common name for alcohol Common name for aldehyde Common name for acid
1 Meth Methyl alcohol (wood alcohol) Formaldehyde Formic acid
2 Eth Ethyl alcohol (grain alcohol) Acetaldehyde Acetic acid
3 Prop Propyl alcohol Propionaldehyde Propionic acid
4 But Butyl alcohol Butyraldehyde Butyric acid
5 Pent Amyl alcohol Valeraldehyde Valeric acid
6 Hex - Caproaldehyde Caproic acid
7 Hept Enanthyl alcohol Enanthaldehyde Enanthoic acid
8 Oct Capryl alcohol Caprylaldehyde Caprylic acid
9 Non - Pelargonaldehyde Pelargonic acid
10 Dec Capric alcohol Capraldehyde Capric acid
11 Undec - - -
12 Dodec Lauryl alcohol Lauraldehyde Lauric acid
13 Tridec - - -
14 Tetradec - Myristaldehyde Myristic acid
15 Pentadec - - -
16 Hexadec Cetyl alcohol Palmitaldehyde Palmitic acid
17 Heptadec - - Margaric acid
18 Octadec Stearyl alcohol Stearaldehyde Stearic acid
19 Nonadec - - -
20 Eicos Arachidyl alcohol - Arachidic acid
21 Heneicos - - -
22 Docos Behenyl alcohol - Behenic acid
24 Tetracos Lignoceryl alcohol - Lignoceric acid
26 Hexacos Cerotinyl alcohol - Cerotinic acid
28 Octacos Montanyl alcohol - Montanic acid
30 Triacont Melissyl alcohol - Melissic acid

Ketones

Common names for ketones can be derived by naming the two alkyl or aryl groups bonded to the carbonyl group as separate words followed by the word ketone. An alkyl is a univalent radical containing only carbon and hydrogen atoms arranged in a chain. ... In the context of organic molecules, aryl refers to any member of the set of functional groups or substituents that are derived from a simple aromatic ring. ... In chemistry, a carbonyl group is a functional group composed of an atom of carbon double-bonded to an atom of oxygen. ...

The first three of the names shown above are still considered to be acceptable IUPAC names. The chemical compound acetone (also known as propanone, dimethyl ketone, 2-propanone, propan-2-one and β-ketopropane) is the simplest representative of the ketones. ... Acetophenone is a crystalline ketone that is used as a solvent for cellulose ethers and esters in the manufacture of alcohol-soluble resins. ... Benzophenone, also known as diphenylmethanone, phenyl ketone, diphenyl ketone, or benzoylbenzene. ... Ethyl isopropyl ketone or 2-methyl-3-pentanone (CAS registry 565-69-5) is an aliphatic ketone with molecular formula (CH3)2CHC=OC2H5. ... 3-Pentanone, also known as diethyl ketone, is a colorless liquid ketone with an odor like that of acetone. ...


Aldehydes

The common name for an aldehyde is derived from the common name of the corresponding carboxylic acid by dropping the word acid and changing the suffix from -ic or -oic to -aldehyde. An aldehyde. ... Structure of a carboxylic acid The 3D structure of the carboxyl group A space-filling model of the carboxyl group Carboxylic acids are organic acids characterized by the presence of a carboxyl group, which has the formula -C(=O)OH, usually written -COOH or -CO2H. [1] Carboxylic acids are Bronsted...

The chemical compound formaldehyde (also known as methanal) is a gas with a pungent smell. ... R-phrases , , S-phrases , , , Flash point −39 °C Autoignition temperature 185 °C RTECS number AB1925000 Supplementary data page Structure and properties n, εr, etc. ...

Ions

The IUPAC nomenclature also provides rules for naming ions. An electrostatic potential map of the nitrate ion (NO3−). Areas coloured red are lower in energy than areas colored yellow robert ford An ion is an atom or group of atoms which have lost or gained one or more electrons, making them negatively or positively charged. ...


Hydron

Hydron is a generic term for hydrogen cation; protons, deuterons and tritons are all hydrons. In chemistry, hydron is the general name for the positive hydrogen H+ cation. ...


Parent hydride cations

Simple cations formed by adding a hydron to a hydride of a halogen, chalcogen or nitrogen-family element are named by adding the suffix "-onium" to the element's root: H4N+ is ammonium, H3O+ is oxonium, and H2F+ is fluoronium. Ammonium was adopted instead of nitronium, which commonly refers to NO2+. The chalcogens (with the ch pronounced with a hard c as in chemistry) are the name for the periodic table group 16 (old-style: VIB or VIA) in the periodic table. ...


If the cationic center of the hydride is not a halogen, chalcogen or nitrogen-family element then the suffix "-ium" is added to the name of the neutral hydride after dropping any final 'e'. H5C+ is methanium, HO-O+H2 is dioxidanium (HO-OH is dioxidane), and H2N-N+H3 is diazanium (H2N-NH2 is diazane).


Cations and substitution

The above cations except for methanium are not, strictly speaking, organic, since they do not contain carbon. However, many organic cations are obtained by substituting another element or some functional group for a hydrogen.


The name of each substitution is prepended to the hydride cation name. If many substitutions by the same functional group occur, then the number is indicated by prepending "di-", "tri-" as with halogenation. (CH3)3O+ is trimethyloxonium. CH3F3N+ is trifluoromethylammonium.


See also

The IUPAC nomenclature of inorganic chemistry is a systematic method of naming inorganic chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC). ... For compounds found in organic chemistry, the Cahn Ingold Prelog priority rules are used to determine the orientation of a molecule for purposes of assigning stereochemistry at a stereocenter and for assigning the name of isomers of molecules possessing double bonds such as alkenes. ...

References

  1. ^  Nomenclature of Organic Chemistry, Oxford: Pergamon Press, 1979; A Guide to IUPAC Nomenclature of Organic Compounds, Recommendations 1993, Oxford: Blackwell Scientific Publications, 1993.

External links

  • IUPAC Nomenclature of Organic Chemistry (online version of the "Blue Book")
  • IUPAC Recommendations on Organic & Biochemical Nomenclature, Symbols, Terminology, etc. (includes IUBMB Recommendations for biochemistry)
  • Bibliography of IUPAC Recommendations on Organic Nomenclature (last updated 2003-04-11)
  • ACD/Name Software for generating systematic nomenclature
  • G. A. Eller, Improving the Quality of Published Chemical Names with Nomenclature Software. Molecules 2006, 9, 915-928 |(online article)

  Results from FactBites:
 
Organic Chemistry - WWW Chemistry Guide (506 words)
Organic Chemistry is the branch of chemistry in which covalent carbon compounds and their reactions are studied.
Organic chemists determine the structures of organic molecules, study their various reactions, and develop procedures for the synthesis of organic substances.
Organic Syntheses presents to the organic chemistry community detailed experimental methods in a standard format for the synthesis of organic compounds in its annual publications and on its free website.
IUPAC nomenclature of organic chemistry - Wikipedia, the free encyclopedia (2327 words)
The IUPAC nomenclature of organic chemistry is a systematic way of naming organic chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC).
In IUPAC nomenclature, a number of prefixes, suffixes and infixes are used to describe the type and position of functional groups in the compound.
The IUPAC nomenclature scheme becomes rapidly more elaborate for more complex cyclic structures, with notation for compounds containing conjoined rings, and many common names such as phenol, furan, indole, etc. being accepted as base names for compounds derived from them.
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