Short Summary of IUPAC Nomenclature of Organic Compounds
Introduction
The purpose of the IUPAC system of nomenclature is to establish an international standard of
naming compounds to facilitate communication. The goal of the system is to give each structure
a unique and unambiguous name, and to correlate each name with a unique and unambiguous
structure.
I. Fundamental Principle
IUPAC nomenclature is based on naming a molecule’s longest chain of carbons connected by
single bonds, whether in a continuous chain or in a ring. All deviations, either multiple bonds or
atoms other than carbon and hydrogen, are indicated by prefixes or suffixes according to a
specific set of priorities.
II. Alkanes and Cycloalkanes
Alkanes are the family of saturated hydrocarbons, that is, molecules containing carbon and
hydrogen connected by single bonds only. These molecules can be in continuous chains (called
linear or acyclic), or in rings (called cyclic or alicyclic). The names of alkanes and cycloalkanes
are the root names of organic compounds. Beginning with the five-carbon alkane, the number of
carbons in the chain is indicated by the Greek or Latin prefix. Rings are designated by the prefix
“cyclo”. (In the geometrical symbols for rings, each apex represents a carbon with the number of
hydrogens required to fill its valence.)
CH4 methane CH3[CH2]10CH3 dodecane
CH3CH3 ethane CH3[CH2]11CH3 tridecane
CH3CH2CH3 propane CH3[CH2]12CH3 tetradecane
CH3[CH2]2CH3 butane CH3[CH2]18CH3 icosane
CH3[CH2]3CH3 pentane CH3[CH2]19CH3 henicosane
CH3[CH2]4CH3 hexane CH3[CH2]20CH3 docosane
CH3[CH2]5CH3 heptane CH3[CH2]21CH3 tricosane
CH3[CH2]6CH3 octane CH3[CH2]28CH3 triacontane
CH3[CH2]7CH3 nonane CH3[CH2]29CH3 hentriacontane
CH3[CH2]8CH3 decane CH3[CH2]38CH3 tetracontane
CH3[CH2]9CH3 undecane CH3[CH2]48CH3 pentacontane
H H
C
H H
C C
cyclopropane H H cyclobutane cyclopentane
cyclohexane cycloheptane cyclooctane
, III. Nomenclature of Molecules Containing Substituents and Functional Groups
A. Priorities of Substituents and Functional Groups
LISTED HERE FROM HIGHEST TO LOWEST PRIORITY, except that the substituents within
Group C have equivalent priority.
Group A—Functional Groups Indicated By Prefix Or Suffix
Family of Compound Structure Prefix Suffix
O
Carboxylic Acid R C OH carboxy- -oic acid
O (-carboxylic acid)
Aldehyde R C H oxo- -al
O (formyl) (carbaldehyde)
Ketone R C R oxo- -one
Alcohol R O H hydroxy- -ol
Amine R N amino- -amine
Group B—Functional Groups Indicated By Suffix Only
Family of Compound Structure Prefix Suffix
Alkene C C -------- -ene
Alkyne C C -------- -yne
Group C—Substituents Indicated by Prefix Only
Substituent Structure Prefix Suffix
Alkyl (see list below) R— alkyl- ----------
Alkoxy R— O — alkoxy- ----------
Halogen F— fluoro- ----------
Cl — chloro- ----------
Br — bromo- ----------
I— iodo- ----------
Group C continued on next page
Introduction
The purpose of the IUPAC system of nomenclature is to establish an international standard of
naming compounds to facilitate communication. The goal of the system is to give each structure
a unique and unambiguous name, and to correlate each name with a unique and unambiguous
structure.
I. Fundamental Principle
IUPAC nomenclature is based on naming a molecule’s longest chain of carbons connected by
single bonds, whether in a continuous chain or in a ring. All deviations, either multiple bonds or
atoms other than carbon and hydrogen, are indicated by prefixes or suffixes according to a
specific set of priorities.
II. Alkanes and Cycloalkanes
Alkanes are the family of saturated hydrocarbons, that is, molecules containing carbon and
hydrogen connected by single bonds only. These molecules can be in continuous chains (called
linear or acyclic), or in rings (called cyclic or alicyclic). The names of alkanes and cycloalkanes
are the root names of organic compounds. Beginning with the five-carbon alkane, the number of
carbons in the chain is indicated by the Greek or Latin prefix. Rings are designated by the prefix
“cyclo”. (In the geometrical symbols for rings, each apex represents a carbon with the number of
hydrogens required to fill its valence.)
CH4 methane CH3[CH2]10CH3 dodecane
CH3CH3 ethane CH3[CH2]11CH3 tridecane
CH3CH2CH3 propane CH3[CH2]12CH3 tetradecane
CH3[CH2]2CH3 butane CH3[CH2]18CH3 icosane
CH3[CH2]3CH3 pentane CH3[CH2]19CH3 henicosane
CH3[CH2]4CH3 hexane CH3[CH2]20CH3 docosane
CH3[CH2]5CH3 heptane CH3[CH2]21CH3 tricosane
CH3[CH2]6CH3 octane CH3[CH2]28CH3 triacontane
CH3[CH2]7CH3 nonane CH3[CH2]29CH3 hentriacontane
CH3[CH2]8CH3 decane CH3[CH2]38CH3 tetracontane
CH3[CH2]9CH3 undecane CH3[CH2]48CH3 pentacontane
H H
C
H H
C C
cyclopropane H H cyclobutane cyclopentane
cyclohexane cycloheptane cyclooctane
, III. Nomenclature of Molecules Containing Substituents and Functional Groups
A. Priorities of Substituents and Functional Groups
LISTED HERE FROM HIGHEST TO LOWEST PRIORITY, except that the substituents within
Group C have equivalent priority.
Group A—Functional Groups Indicated By Prefix Or Suffix
Family of Compound Structure Prefix Suffix
O
Carboxylic Acid R C OH carboxy- -oic acid
O (-carboxylic acid)
Aldehyde R C H oxo- -al
O (formyl) (carbaldehyde)
Ketone R C R oxo- -one
Alcohol R O H hydroxy- -ol
Amine R N amino- -amine
Group B—Functional Groups Indicated By Suffix Only
Family of Compound Structure Prefix Suffix
Alkene C C -------- -ene
Alkyne C C -------- -yne
Group C—Substituents Indicated by Prefix Only
Substituent Structure Prefix Suffix
Alkyl (see list below) R— alkyl- ----------
Alkoxy R— O — alkoxy- ----------
Halogen F— fluoro- ----------
Cl — chloro- ----------
Br — bromo- ----------
I— iodo- ----------
Group C continued on next page
