Models of Chemical Bonding

A theoretical model which gets used to explain chemical bonds. Not only the chemical bonds but to explain atomic bonding structure, properties, and its reaction as a physical matter. Also, it helps in understanding molecular geometry as well. 

In other words, chemical bonding models help to explain the chemical bond theory but in an easier way. Being theoretical models, these are fruitful in terms of understanding.

For this, we need to know what is bonding. A chemical bond is the lasting attraction of two or more molecules, ions, or atoms to get more stable. Not only that, but it helps the chemical to form basic chemicals and chemical compounds as well.

Models of Chemical Bonding

There are various models for chemical bonding to make it easier to understand. The attraction between two or more molecules in different ways is possible to interpret in various ways. And not the only interpretation; but there are various types of chemical bonds.

All those bonds need to be understandable to everyone. So, naturally, there need to be different chemical bonding models to understand chemical bonding and molecular structure.

There are models known as 

• Molecular Orbital Theory. This one describes a molecular electronic structure with localized molecular orbitals.
• A model of molecular geometry or VSEPR Theory
• An electrostatic model for transition metal complexes or Crystal Field Theory
• Valence Bond Theory describes an electronic structure with localized bonds and lone pairs of the molecule.
• The application of molecular orbital theory transition metal complex or Ligand Field Theory.

Different types of chemical compounds, such as ionic or covalent compounds, can be described so easily through these bond models. First, let us find some more explanations for the models.

Molecular Orbital Theory

This theory describes the molecular electronic structure with the help of quantum mechanics. From the early 20th century, it helps better to understand what is bonding. In this theory, the electrons of a molecule are not fixed for any chemical bond but are accessible under the nuclei. With the help of quantum mechanics, this can be described as the energetic properties of electrons that surround two or more atoms. For this model, the valence electron must be there.

VSEPR Theory

Valence-Shell Electron-Pair Repulsion or VSEPR theory helps to predict the geometry of a molecule. Not only that, but it helps to predict the electron pair which surrounds the central atoms. From this model, it is possible to determine the shape of the molecule, and also, you will be able to know the bonding type for that molecule.

Though this model can not help you to know the bond length or if there are any multiple bonds. Also, this model cannot give any information about the perfect arrangement of atoms.

Crystal Field Theory

This theory describes the breaking of electrons through degeneracies at the orbital state for a static electric field. Surrounding charge distribution produces this static electric field. For transition metal coordination complexes, you can use this model.

This model successfully accounts for some colours, magnetic properties, and spinel structure of the transition of metal complexes. But it won’t help ideally to know what is bonding.

Valence Bond Theory

This is one of the two fundamental theories. The other one is the Molecular Orbital theory. Both of these were made to explain quantum mechanics and describe what bonding is. 

According to this theory, all bonds are localized and can form between two atoms where both of them donate an electron. This theory helps in describing the shape of covalent compounds. Along with these, the valence bond theory describes the electronic structure of molecules.

With the help of this, it is possible to make a strong bond. The atoms will approach one another until the density starts repulsing, and thus, the potential energy for the molecule will be possibly the lowest.

Ligand Field Theory

This theory is an extension and practical application of the Molecular Orbital theory. This describes the bonding, arrangements of orbits, and other characteristics of metal complexes.

So, naturally, this theory analysis requires perfect geometry of the complex. To know what bonding means, you need to remember that the orbitals of proper energy form bonding interactions with ligands.

Conclusion

With various types of models of chemical bonds, it will be easier to know what is bonding. But there is no such perfect model or theory to determine all the effects, sides, size, and shape of a chemical bond.

Some can identify the shape or the bond type. Some can explain different types of compounds perfectly.

As these all are theoretical models, they have some limitations and limitations. For example, they cannot determine the length of a bond or the perfect arrangement of a bond.