Organic Chemistry Prefixes and Suffixes

Organic Chemistry Nomenclature for Hydrocarbons

Propane is a 3-carbon alkane. It is found as a gas or as a compressed liquid. Pro- is the prefix for 3 carbons, while the -ane suffix means there are only single bonds between the carbon atoms.
Propane is a 3-carbon alkane. It is found as a gas or as a compressed liquid. Pro- is the prefix for 3 carbons, while the -ane suffix means there are only single bonds between the carbon atoms. Science Photo Library / Getty Images

The purpose of organic chemistry nomenclature is to indicate how many carbon atoms are in a chain, how the atoms are bonded together, and the identity and location of any functional groups in the molecule. The root names of hydrocarbon molecules are based on whether they form a chain or ring. A prefix to the name comes before the molecule. The prefix of the molecule's name is based on number of carbon atoms.

For example, a chain of six carbon atoms would be named using the prefix hex-. The suffix to the name is an ending that it applied that describes the types of chemical bonds in the molecule. An IUPAC name also includes the names of substituent groups (aside from hydrogen) that make up the molecular structure.

Hydrocarbon Suffixes

The suffix or ending of the name of a hydrocarbon depends on the nature of the chemical bonds between the carbon atoms. The suffix is -ane if all of the carbon-carbon bonds are single bonds (formula CnH2n+2), -ene if at least one carbon-carbon bond is a double bond (formula CnH2n), and -yne is there is at least one carbon-carbon triple bond (formula CnH2n-2). There are other important organic suffixes:

-ol means the molecule is an alcohol or contains the -C-OH functional group

-al means the molecule is an aldehyde or contains the O=C-H functional group

-amine means the molecule is an amine with the -C-NH2 functional group

-ic acid indicates a carboxylic acid, which has the O=C-OH functional group

-ether indicates an ether, which has the -C-O-C- functional group

-ate is an ester, which has the O=C-O-C functional group

-one is a ketone, which has the -C=O functional group

Hydrocarbon Prefixes

This table lists the organic chemistry prefixes up to 20 carbons in a simple hydrocarbon chain.

It would be a good idea to commit this table to memory early in your organic chemistry studies (at least the first 10).

Organic Hydrocarbon Prefixes
PrefixNumber of
Carbon atoms
Formula
meth-1C
eth-2C2
prop-3C3
but-4C4
pent-5C5
hex-6C6
hept-7C7
oct-8C8
non-9C9
dec-10C10
undec-11C11
dodec-12C12
tridec-13C13
tetradec-14C14
pentadec-15C15
hexadec-16C16
heptadec-17C17
octadec-18C18
nonadec-19C19
eicosan-20C20

Halogen substituents are also indicated using prefixes, such as fluoro (F-), chloro (Cl-), bromo (Br-), and iodo (I-). Numbers are used to identify the position of the substituent. For example, (CH3)2CHCH2CH2Br is named 1-bromo-3-methylbutane.

Common Names

Be aware, hydrocarbons found as rings (aromatic hydrocarbons) are named somewhat differently. For example, C6H6 is named benzene. Because it contains carbon-carbon double bonds, the -ene suffix is present. However, the prefix actually comes from the word "gum benzoin", which as an aromatic resin used since the 15th century.

When the hydrocarbons are subsituents, there are several common names you may encounter:

amyl - substituent with 5 carbons

valeryl - substituent with 6 carbons

lauryl - subsituent with 12 carbons

myristyl - substituent with 14 carbons

cetyl OR palmityl - substituent with 16 carbons

stearyl - substituent with 18 carbons

phenyl - common name for a hydrocarbon with benzene as a substituent

Format
mla apa chicago
Your Citation
Helmenstine, Anne Marie, Ph.D. "Organic Chemistry Prefixes and Suffixes." ThoughtCo, May. 2, 2017, thoughtco.com/hydrocarbon-nomenclature-prefixes-608208. Helmenstine, Anne Marie, Ph.D. (2017, May 2). Organic Chemistry Prefixes and Suffixes. Retrieved from https://www.thoughtco.com/hydrocarbon-nomenclature-prefixes-608208 Helmenstine, Anne Marie, Ph.D. "Organic Chemistry Prefixes and Suffixes." ThoughtCo. https://www.thoughtco.com/hydrocarbon-nomenclature-prefixes-608208 (accessed November 21, 2017).