As indicated above, three longest chains are possible each with seven carbons, but again the same questions peeps into our mind, which should be selected as parent chain In contrast to previous example, all these longest chains are not identical hence only one of them will win the competition.

Interestingly, its valency is four and if it is attached with four hydrogens it forms simple hydrocarbon methane.

Alkanes are the saturated hydrocarbons without any functional group so IUPAC naming is somewhat easy So, lets go with simple examples initially and then to more advanced structures of alkanes.

Writing IUPAC name of alkane is very simple and direct method where -ane is used as suffix to indicate alk ane s.

We can select a suitable prefix based on the number of carbons in the parent chain and can be combine with suffix to complete the IUPAC name of alkane.

Second structure is Eth aneEthane Third structure is Prop anePropane We can extend this with four carbon chain as butane.

Of course, all the above cited examples are simple straight chain compounds without any branching.

Even isobutane contains four carbons, according to IUPAC rules, we have to select longest chain as parent chain.

Here it contains longest chain with 3 carbons methyl group being attached at second position.

Isopentane Here it has two longest chains and any one can be selected as parent chain.

So if we select one of the chains, it contains four carbons hence prefix is But-.

Now methyl group is present as side chain at 2 nd position hence prefix is 2-Methyl.

Combining all these, IUPAC name of alkane in the above example is 2-Methyl But ane2-Methylbutane Thats fine, lets make another step.

Neopentane In case of neopentane, the longest chain contains only three carbons, hence the root name is Prop-.

Other two methyl groups are considered as side chains which are attached at second position, therefore indicated by 2,2-Dimethyl.

Combining all, IUPAC name of neopentane is 2,2-dimethylpropane Higher alkanes Now lets go with more advanced examples and lets apply all IUPAC rules to get the name.

Consider the following structure Since we are naming alkanes, our first role is to identify the longest chain.

If you observe the structure, three types of chains are possible two chains each with 6 carbons and another chain with 5 carbons.

Then, which of the above chains should be selected as parent chain Obviously, the chain indicated by red colored numbering contains only 5 carbons hence not the longest chain and therefore not considered as parent chain.

Which is going to win Interestingly both the chains are similar having same side chains.

Going with one of that, now you can easily find that two side chains are present at 3 rd and 4 th positions, which are, of course, same and since they contain two carbons, we have to use prefix 3,4 di ethyl 3,4-diethyl As the parent chain contains six carbons, the root name is hex.

Finally, combining all we can put the name as 3,4-Diethylhexane.

So, simple it is, isnt it Lets go further with naming of alkane having more branching.

As with the previous example, here again we have to identify the longest chain and so many possibilities arise in selection of parent chain.

Iupac Naming Examples