Branched Molecules

Not all chains are straight - indeed in crude oil, the majority of molecules present are branched. Any hydrocarbon with six carbons and fourteen hydrogens will be a hexane, but when branching is considered many different chemical structures are possible - these are called 'isomers'.

It is also possible to have the double bond in a place other than between the 1st and 2nd carbons in the chain. The table we showed you earlier only showed 1-alkenes, however the other possible alkenes are shown in the table below.

Below are the branched and unbranched molecules for a few of the alkanes and alkenes.

4 Carbons

n-butane i-butane (2-methylpropane)
1-butene 2-butene 2-methylpropene

5 Carbons

n-pentane i-pentane (2-methylbutane) tert-pentane (2,2-dimethylpropane)
1-pentene trans-2-pentene cis-2-pentene 3-methyl-1-pentene 2-methyl-2-pentene 2-methyl-1-pentene

6 Carbons

n-hexane 3-methylpentane 2,2-dimethylbutane 2-methylpentane 2,3-dimethylbutane
1-hexene trans-2-hexene cis-2-hexene trans-3-hexene cis-3-hexene 4-methyl-1-pentene 2-methyl-2-pentene 2-methyl-1-pentene trans-4-methyl-2-pentene cis-4-methyl-2-pentene 2,3-dimethyl-2-butene 2,3-dimethyl-1-butene 3,3-dimethyl-1-butene 3-methyl-1-pentene 2-ethyl-1-butene (E)-3-methyl-2-pentene (Z)-3-methyl-2-pentene