ORGANIC NOMENCLATURE

Nomenclature of hydrocarbons. 
Aliphatic hydrocarbons.
Saturated hydrocarbons: alkanes.
a)	Linear: These are named with a prefix indicating the number of carbon atoms, and the –ANE termination. 

b)	Branched: the branches (radicals) formed by carbon and hydrogen atoms, are named using the corresponding prefix, according to the number of carbon atoms (as for linear alkanes), with the –YL termination. 

In order to name the branched hydrocarbons the following steps must be followed:
1.	Enumerate the longer (parent) chain, beginning by the extreme closer to the radical. 
2.	The radical is named and numbered, and written before the name of the parent chain. 
3.	If one radical appears more than once, its name is preceded by a prefix indicating the number of these radicals (di-, tri- tetra-...)
4.	Different radicals are named in alphabetical order, numbers beginning by the extreme closer to a radical. 

a) Alkenes. 
These are hydrocarbons with double bonds. In order to name these hydrocarbons:
1. Those with just one double bond are named changing the termination -ANE for –ENE, indicating with a number the position of the double bond (Counting from the extreme closer to the double bond). 
2. If branches are founded, the principal chain will be the longer one which includes the double bond, and counting will begin so that the double bond has the lower localizer. 
3. If it has more than a double bond then the suffix will be -DIENE, -TRIENE, -TETRAENE... 

c) Alkynes.
These are hydrocarbons with triple bonds. They are named as follows:
1. Those with just one double bond change their termination –ANE for -INE indicating with a number the position of the triple bond (counting from the extreme that is closer to the triple bond). 
2. If branches are found and/or more than a triple bond is present, instructions are the same as for alkenes. 
3. If double and triple bonds are found together then they are named in -ENE –YNE order, with the lowest possible localizers, independently of the unsaturation being double or triple. 
4. When the branches have unsaturations as well, the principal chain will be the one that fulfils the following requirements: 
1.	Higher number of unsaturations. 
2.	Higher number of carbon atoms. 
3.	Higher number of double bonds. 

6-methyl-1,4-heptadiyne	3-propyl-5,7-nonadien-1-yne     2-methyl-7-(1-propenyl)-3,8-undecadien-5-yne