An organic compound can be designated by molecular or structural formula. It
gives a concise and instantly recognizable description of the compound.
Molecular formula : It is the formula which expresses the exact number
of atoms of each element present in the molecule and does not distinguish
between isomers.
Structural formula : It describes the actual attachment of all atoms
with one another in the molecule and distinguishes between isomers.
The following table illustrates how these formulae are used to represent
the compound.
Note that entries 2 and 3 have similar molecular formulae but different
structural formula. Such compounds are called
isomers. Structure
affects both the chemical reactivity and physical properties of compounds as
illustrated in following
