Valence Bond Theory: Statements and Drawbacks of VBT

Hey guys, in this article we are going to discuss about Valence Bond Theory as it is seems to the title of the post.

First we will study on VBT and then we’ll discuss the Drawbacks of VBT.

In this way, I think it will be helpful to understand the whole thing more easily.

So, first let us see the Statements of VBT. Let’s see what VBT says.

Statements of VBT :

These are the following statements of VALENCE BOND THEORY.

1. According to this theory, in a complex compound, the Central Metral Atom(C.M.A) work as a lewis acid and ligands work as lewis base. So, they are connected by Co-ordinate bond.
2. On the basis of the strength of ligand, complex compound defined itself by two way. One is called “Outer d complex” and another is called “Inner d complex”.
3. Strength of ligands depend on their basic strength.
4. Where ‘d’ orbital of C.M.A utilize in hybridization in inner’d’ complex.
5. Those complex compound which contain unpaired electron, are paramagnetic in nature.

So these are the statements of Valence Bond theory.

Now lets see the limitations of VBT.

Drawbacks

1. VBT doesn’t follow Hund’s Law
2. This theory is not able to explain strength of ligands.
3. VBT also not able to explain color behavior of complex compound.
4. Also this theory not able to describe the magnetic strength of the complex compounds.

After these drawbacks of VBT, a new theory comes to place named CFT(Crystal Field Theory).

Thank you that’s all.