Some Common Organic Functional Groups

Traditional Name
IUPAC Name
Functional Group
General Formula
Example
alkane*
(saturated
hydrocarbon)
alkane
none
R or CnH2n+2

ethane

olefin, alkene*
(unsaturated
hydrocarbon)
alkene
C=C
R or CnH2n
ethene
(ethylene)
alkyne*
(unsaturated
hydrocarbon)
alkyne
C?C
R or CnH2n-2
ethyne
(acetylene)
aromatic hydrocarbon
arene
-C6H5 
(benzene ring or phenyl group)
R-C6H5 or R-?

benzene

alkyl halide or halogenated hydrocarbon
haloalkane
-X 
(X = F, Cl, Br, I)
R-X
chloroethane
(ethyl chloride)

alcohol

alkanol
-OH
R-OH
ethanol
(ethyl alcohol)
mercaptan
thiol

 -SH

R-SH
ethanethiol
(ethyl mercaptan)

ether

ether
-O-
R-O-RÕ
diethyl ether

carboxylic acid 

alkanoic acid
 O
  || 		¤
-C-OH
R-COOH
ethanoic acid
(acetic acid)

ester

ester
 O
  ||		¤
-C-O-
R-COO-RÕ
ethyl ethanoate

ketone 

alkanone
 O       
  ||		¤
-C-
R-CO-RÕ
propanone
(acetone)

aldehyde

alkanal
 O
  ||		¤
-C-H
R-CHO
methanal
(formaldehyde)

acid halide

acyl halide
 O
  ||		¤
-C-X  (X = F, Cl, Br, I)
R-COX
ethanoyl chloride

nitro compounds

nitro compounds
-NO2
R-NO2 
nitroethane

amine 

amine
-NH2		×
R-NH2 
ethanamine
(ethylamine)
amide 
amide
 O
  ||	          ¤ ×
-C-NH2
R-CONH2
ethanamide
(acetamide)
Turn over for some additional notes  (explanations of * ¤ ×)

Additional Notes 

*  Alkanes, alkenes, and alkynes are collectively known as aliphatic compounds (meaning that they are NOT aromatic)

¤  There are many functional groups which contain a C=O unit.  This C=O group by itself is called a carbonyl group, and is found within many other functional groups.

×  Amines in which the nitrogen is attached to two HÕs (R-NH2) are called primary amines, and are the most common.  However secondary, tertiary, and even quaternary amines also exist with two, three, and four bonds to carbon (respectively).  Secondary amines have only one hydrogen bonded to the nitrogen, and tertiary amines have none.  For example, trimethyl amine can be written: (CH3)3N 
Quaternary amines carry a positive charge on the N.  

×  Amides, like amines, can be primary (with two bonds to H, as in R-CONH2), secondary, or tertiary.  For example, a tertiary amide might be written (using a skeletal structure) like this: