Structural Isomers are molecules which have the same molecular
formula but have different connectivity's (The Order They Are
Put Together).
Alkanes
can be very simple examples of this.
With the structural formula C4H10 there are two
different isomers possible.
As the number of Carbons in an alkane increases the number of
structural isomers also increases. This happens quite dramatically
as is shown by the following table.
Number of Isomers of Alkanes
Number of C Atoms
Possible Isomers
1-3
1
4
2
5
3
6
5
7
9
8
18
9
35
10
75
15
4,347
20
366,319
Another simple example of Structural Isomerism is that between
Alcohols and Ethers.
The molecular formula of both Ethanol (An Alcohol) and Methoxymethane
(An Ether) is
C2H6O.