Naming Simple Organic Compounds

Turning the formula of an organic compound into a name involves two pieces separate (but related) ideas.

The first part of the name indicates the number of carbon atoms in the formula using the list below:

1 - meth

2 - eth

3 - prop

4 - but

5 - pent

6 - hex

7 - hept

8 - oct

9 - non

10 - dec

The second part of the name needs to indicate the type of bonding that occurs in the compound - specifically, whether the compound contains only single bonds or whether it contains a double or triple bond. The name may also need to indicate the presence of an OH group.

The easiest of these to spot are the alcohols. Any formula that ends in OH will have the ending "anol." So, C₃H₇OH is propanol - "prop" because there are 3 carbon atoms and "anol" for the OH group.

If there is no OH group, you need to think about the number of hydrogen atoms present. Alkanes contain two MORE than twice the number of carbons. Alkenes contain exactly twice the number of carbons and alykynes contain two less than twice the number of carbons.

All of that is simpler written as formulas:

"ane" = C_xH_(2x+2)
"ene" =  C_xH_(2x)
"yne" = C_xH_(2x-2)

So, C₉H₁₈, would be nonene - "non" for the 9 carbons, and "ene" becuase there are twice as many hydrogen atoms as carbons.

Try these to make sure you understand. The answers are here.

C₆H₁₄
C₃H₄
CH₄
C₇H₁₄
C₇H₁₅OH
C₂H₂