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In organic chemistry, 'functional groups' (or moieties) are specific groups of atoms within molecules, that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction(s) regardless of the size of the molecule it is a part of.
Combining the names of functional groups with the names of the parent alkanes generates a powerful systematic nomenclature for naming organic compounds.
The non-hydrogen atoms of functional groups are always associated with each other and with the rest of the molecule by covalent bonds. When the group of atoms is associated with the rest of the molecule primarily by ionic forces, the group is referred to more properly as a polyatomic ion or complex ion. And all of these are called radicals, by a meaning of the term ''radical'' that predates the free radical.
The first carbon atom after the carbon that attaches to the functional group is called the alpha carbon.
Functional groups are attached to the carbon backbone of organic molecules. They determine the characteristics and chemical reactivity of molecules. Functional groups are far less stable than the carbon backbone and are likely to participate in chemical reactions.
= Table of common functional groups =
The following is a list of common functional groups. In the formulas, the symbols R and R' usually denote an attached hydrogen, or a hydrocarbon side chain of any length, but may sometimes refer to any group of atoms.

Contents

Hydrocarbons

Groups containing halogens

Groups containing oxygen

Groups containing nitrogen

Groups containing phosphorus and sulfur

Other

See also

External links

Hydrocarbons

Functional groups which vary based upon the number and order of π bonds impart different chemistry. Each listing below contains C-H bonds, but each one differs in type (and scope) of reactivity.

Chemical class	Group	Formula	Structural Formula	Prefix	Suffix	Example
Alkane	Alkyl	RH	Alkyl	alkyl-	-ane	methane Methane
Alkene	Alkenyl	R2C=CR2	Alkene	alkenyl-	-ene	ethylene Ethylene ''(Ethene)''
Alkyne	Alkynyl	RC≡CR'	Alkyne	alkynyl-	-yne	acetylene Acetylene ''(Ethyne)''
Benzene derivative	Phenyl	RC6H5	Phenyl	phenyl-	-benzene	Cumene Cumene ''(2-phenylpropane)''
Toluene derivative	Benzyl	RCH2C6H5 RBn	Benzyl	benzyl-	1-(''substituent'')toluene	Benzyl bromide Benzyl bromide ''(1-Bromotoluene)''

Groups containing halogens

Haloalkanes are a class of molecule which is defined by a carbon-halogen bond. This bond can be relatively weak (in the case of an iodoalkane) or quite stable (as in the case of a fluoroalkane). In general, with the exception of fluorinated compounds, haloalkanes readily undergo nucleophilic substitution reactions or elimination reactions. The substitution on the carbon, the acidity of an adjacent proton, the solvent conditions, etc. all can influence the outcome of the reactivity.

Chemical class	Group	Formula	Structural Formula	Prefix	Suffix	Example
haloalkane	halo	RX	Halide group	halo-	alkyl 'halide'	Chloroethane Chloroethane ''(Ethyl chloride)''
fluoroalkane	fluoro	RF	Fluoro group	fluoro-	alkyl 'fluoride'	Fluoromethane Fluoromethane ''(Methyl fluoride)''
chloroalkane	chloro	RCl	Chloro group	chloro-	alkyl 'chloride'	Chloromethane Chloromethane ''(Methyl chloride)''
bromoalkane	bromo	RBr	Bromo group	bromo-	alkyl 'bromide'	Bromomethane Bromomethane ''(Methyl bromide)''
iodoalkane	iodo	RI	Iodo group	iodo-	alkyl 'iodide'	Iodomethane Iodomethane ''(Methyl iodide)''

Groups containing oxygen

Compounds which contain C-O bonds each possess differing reactivity based upon the location and hybridization of the C-O bond, owing to the electron-withdrawing effect of sp² hybridized oxygen and the donating effects of sp³ hybridized oxygen.

Chemical class	Group	Formula	Structural Formula	Prefix	Suffix	Example
Acyl halide	Haloformyl	RCOX	Acyl halide	haloformyl-	-oyl halide	Acetyl chloride Acetyl chloride ''(Ethanoyl chloride)''
Alcohol	Hydroxyl	ROH	Hydroxyl	hydroxy-	-ol	methanol Methanol
Ketone	Carbonyl	RCOR'		keto-, oxo-	-one	Butanone Methyl ethyl ketone ''(Butanone)''
Aldehyde	Aldehyde	RCHO	Aldehyde	aldo-	-al	acetaldehyde Acetaldehyde ''(Ethanal)''
Carbonate	Carbonate ester	ROCOOR	Carbonate		alkyl 'carbonate'
Carboxylate	Carboxylate	RCOO−	Carboxylate Carboxylate	carboxy-	-oate	Sodium acetate Sodium acetate ''(Sodium ethanoate)''
Carboxylic acid	Carboxyl	RCOOH	Carboxylic acid	carboxy-	-oic acid	Acetic acid Acetic acid ''(Ethanoic acid)''
Ether	Ether	ROR'	Ether	alkoxy-	alkyl alkyl 'ether'	Diethyl ether Diethyl ether ''(Ethoxyethane)''
Ester	Ester	RCOOR'			alkyl alkan'oate'	Ethyl butyrate Ethyl butyrate ''(Ethyl butanoate)''
Hydroperoxide	Hydroperoxy	ROOH	Hydroperoxy	hydroperoxy-	alkyl 'hydroperoxide'	Methyl ethyl ketone peroxide Methyl ethyl ketone peroxide
Peroxide	Peroxy	ROOR	Peroxy	peroxy-	alkyl 'peroxide'	Di-tert-butyl peroxide Di-tert-butyl peroxide

Groups containing nitrogen

Compounds which contain Nitrogen in this category may contain C-O bonds, such as in the case of amides.

Chemical class	Group	Formula	Structural Formula	Prefix	Suffix	Example
Amide	Carboxamide	RCONR2	Amide	carboxamido-	-amide	acetamide Acetamide ''(Ethanamide)''
Amines	Primary amine	RNH2	Primary amine	amino-	-amine	methylamine Methylamine ''(Methanamine)''
	Secondary amine	R2NH	Secondary amine	amino-	-amine	dimethylamine Dimethylamine
	Tertiary amine	R3N	Tertiary amine	amino-	-amine	trimethylamine Trimethylamine
	4° ammonium ion	R4N+	Quaternary ammonium cation	ammonio-	-ammonium	choline Choline
Imine	Primary ketimine	RC(=NH)R'	Imine	imino-	-imine
	Secondary ketimine	RC(=NR'')R'	Imine	imino-	-imine
	Primary aldimine	RC(=NH)H	Imine	imino-	-imine
	Secondary aldimine	RC(=NR')H	Imine	imino-	-imine
Imide	Imide	RC(=O)NC(=O)R'	Imide	imido-	-imide
Azide	Azide	RN3	Organoazide	azido-	alkyl 'azide'	Phenyl azide Phenyl azide (Azidobenzene)
Azo compound	Azo (Diimide)	RN2R'	Azo.pngl	azo-	-diazene	Methyl orange Methyl orange (p-dimethylamino-azobenzenesulfonic acid)
Cyanates	Cyanate	ROCN	Cyanate	cyanato-	alkyl 'cyanate'
	Isocyanide	RNC	Isocyanide	isocyano-	alkyl 'isocyanide'
Isocyanates	Isocyanate	RNCO	Isocyanate	isocyanato-	alkyl 'isocyanate'	Methyl isocyanate Methyl isocyanate
	Isothiocyanate	RNCS	Isothiocyanate	isothiocyanato-	alkyl 'isothiocyanate'	Allyl isothiocyanate Allyl isothiocyanate
Nitrate	Nitrate	RONO2	Nitrate	nitrooxy-, nitroxy-	alkyl 'nitrate'	Amyl nitrate Amyl nitrate ''(1-nitrooxypentane)''
Nitrile	Nitrile	RCN	Nitrile	cyano-	alkane'nitrile' alkyl 'cyanide'	Benzonitrile Benzonitrile ''(Phenyl cyanide)''
Nitrite	Nitrosooxy	RONO	Nitrite	nitrosooxy-	alkyl 'nitrite'	Amyl nitrite Amyl nitrite ''(3-methyl-1-nitrosooxybutane)''
Nitro compound	Nitro	RNO2	Nitro	nitro-		Nitromethane Nitromethane
Nitroso compound	Nitroso	RNO	Nitroso	nitroso-		Nitrosobenzene Nitrosobenzene
Pyridine derivative	Pyridyl	RC5H4N	4-pyridyl group 3-pyridyl group 2-pyridyl group	4-pyridyl (pyridin-4-yl) 3-pyridyl (pyridin-3-yl) 2-pyridyl (pyridin-2-yl)	-pyridine	Nicotine Nicotine

Groups containing phosphorus and sulfur

Compounds which contain sulfur and phosphorus exhibit unique chemistry due to their ability to form more bonds than nitrogen and oxygen, their lighter analogues on the periodic table.

Chemical class	Group	Formula	Structural Formula	Prefix	Suffix	Example
Phosphine	Phosphino	R3P	A tertiary phosphine	phosphino-	-phosphane	Methylpropylphosphane Methylpropylphosphane
Phosphodiester	Phosphate	HOPO(OR)2	Phosphodiester	phosphoric acid di(''substituent'') ester	di(''substituent'') hydrogenphosphate	DNA
Phosphonic acid	Phosphono	RP(=O)(OH)2	Phosphono group	phosphono-	''substituent'' phosphonic acid	Benzylphosphonic acid Benzylphosphonic acid
Phosphate	Phosphate	ROP(=O)(OH)2	Phosphate group	phospho-		Glyceraldehyde 3-phosphate Glyceraldehyde 3-phosphate
Sulfide or thioether		RSR'	Sulfide group		di(''substituent'') sulfide	Dimethyl sulfide Dimethyl sulfide
Sulfone	Sulfonyl	RSO2R'	Sulfonyl group	sulfonyl-	di(''substituent'') sulfone	Dimethyl sulfone Dimethyl sulfone ''(Methylsulfonylmethane)''
Sulfonic acid	Sulfo	RSO3H	Sulfonyl group	sulfo-	''substituent'' 'sulfonic acid'	Benzenesulfonic acid Benzenesulfonic acid
Sulfoxide	Sulfinyl	RSOR'	Sulfinyl group	sulfinyl-	di(''substituent'') 'sulfoxide'	Diphenyl sulfoxide Diphenyl sulfoxide
Thiol	Sulfhydryl	RSH	Sulfhydryl	mercapto-, sulfanyl-	-thiol	Ethanethiol Ethanethiol ''(Ethyl mercaptan)''
Thiocyanate	Thiocyanate	RSCN	Thiocyanate	thiocyanato-	alkyl 'thiocyanate'
Disulfide	Disulfide	RSSR'	Disulfide		alkyl alkyl disulfide	Diphenyl disulfide Diphenyl disulfide ''1,2-diphenyldisulfane''

Other

★ Methyl

★ Methylene

★ Ethyl

★ Propyl

★ Butyl

★ Hydroxy

★ Methoxy

★ Hydroxymethyl

★ Methylenedioxy

★ Phenyl

★ Acetyl

★ Acetoxy

See also

★ Compendium of Chemical Terminology (IUPAC "Gold Book")

External links

★ IUPAC Blue Book (organic nomenclature)

★ IUPAC ligand abbreviations (pdf)