Definition of structural formula & how Determination of structural formula?

Structural formula  

Definition;

The structural formula of a compound shows the exact picture as to how the various atoms are bonded to each other in a formula.

As the Google map show the exact path of the destination.                                            For example, structural formula of ethane is

How the structural formula of an organic compound can be determined?

We can determine the structural formula by using traditional analytical method and spectroscopic method.

traditional analytical method;

it consist three steps;

1: identification of functional groups; the various functional groups such as –OH, -CHO, -COOH etc. are identified by their specific chemical test.

2: degradation into simpler molecule; large molecule are broken down to simpler one by oxidation, reduction, hydrolysis etc. each fragment is identified by the usual chemical tests. The probable molecular model is then constructed by working back through the various stages of degradation.

3: confirmation by synthesis; the compound under investigation is now synthesized from simple molecules of known structure. If the synthetic compound has the same melting point as the original compound. The structure of latter stand is confirmed.

Spectroscopic method;

in the recent year, the spectroscopic methods have almost superseded the traditional methods. The chief advantages of these newer methods are there remarkable precision and the extremely small quantity of the material required. The three important methods that are commonly used in modern practice are;

a)    Infrared spectroscopy (IR)

b)    Ultraviolet and visible spectroscopy (UV)

c)     Nuclear magnetic resonance spectroscopy(NMR)