Functional Groups - Alkanes

Alkanes



Name Functional Group
Structure 		Example Compound Official Name of Example
(Common Name)
Formal Name Ending
alkane none
(all carbon-carbon
single bonds) 		ethane
(ethane)
-ane endings


Hydrocarbons (compounds composed only of carbon and hydrogen) that contain only carbon-carbon single bonds are called alkanes. They are named using a prefix that designates the number of carbon atoms in the molecule and the suffix -ane (see below).

Name Formula Name Formula
methane CH4 pentane C5H12
ethane C2H6 hexane C6H14
propane C3H8 heptane C7H16
butane C4H10 octane C8H18

The names shown above correspond to what are called straight chains. In straight chains, each middle carbon is bonded to two other carbons and two hydrogens. The end carbons are bonded to only one carbon, but three hydrogens.

is pentane


When the carbons are not all in a straight chain, the alkane is said to be branched. The rules for naming branched alkanes are more involved, but are equally systematic (if you wish to learn more about naming branched compounds, consult your textbook). When the carbons form a ring they are given the prefix cyclo-.

is cyclohexane


Continue reading about alkenes and alkynes.


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