Nomenclature: Linear Alkanes

Background

Alkanes are saturated hydrocarbons (molecules consisting only of carbon and hydrogen with no double or triple bonds). These compounds can be grouped according to their structures. Linear (or straight-chain) alkanes are straight chains of carbons, branched alkanes have hydrocarbon substituents coming off of a linear alkane chain, and cyclic alkanes have one or more rings. Here are simple examples of these three groups:

Basic Alkane Structures

It is important to learn the names of the linear alkanes, as these names are the basis for naming almost all of the other types of organic molecules.

Nomenclature

The following table shows the names of the most common linear alkanes. You will want to memorize these.

Nomenclature - Linear Alkanes

Click here for a quiz where you can practice the names of the linear alkanes.

Notice that all of these names end in the suffix -ane. This suffix is used for all alkanes, and is also used for alkyl halides (that is, alkanes with fluorine, chlorine, bromine, or iodine substituents).

Apart from the names of the first four alkanes (methane, ethane, propane, and butane), the first parts of these alkane names have roots in the Greek and Latin prefixes for numbers.

You will sometimes see these linear alkane names with an n– prefix (for example, n-butane). This prefix (which stands for normal) may be used to specify the linear form of the alkane (to differentiate it from branched structural isomers). However, in the IUPAC nomenclature system, this prefix is not used, and the names in the table above refer to the linear structures.

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