What is Resonance Theory?
Resonance structures are defined as a group of two or more Lewis structures that can collectively represent a single polyatomic species. These display the electronic bonding between the metals, including the fractional bonds and the fractional charges.
This can be described as the combination of several contributing structures that leads to the formation of hybrid resonance structures in accordance with the valence bond theory, which is the association of certain molecules and ions.
In most cases, a single Lewis structure fails to explain the bonding in a molecule due to the presence of partial charges and fractional bonds. In these circumstances, the resonance structures will lead to the chemical bonding.
In the case of the molecules or ions, the bonding happens by merging many contributory structures or forms. There is a resonance structure is described below:
The process of electron delocalization can be explained as fractional bonds. How stable the structure will be will depend on the type of bond that it exhibits. This is known as the Resonance Hybrid. In this case, the resonance structures are not equivalent.
Determining which one(s) best describes the actual bonding will also be essential. The formal charge of the electron bonding can be used to predict the most favorable resonance structure.
TYPES OF RESONANCE
There are four types of resonance, based on the orbital in which the electrons are placed and on the base of the electron bond that exists.
Type 1: This resonance interacts with an empty p-orbital and an adjacent electron pair. This is circulating in terms of the simple π-bond. This type of resonance structure will result in a structure analogous to a simple π-bond.
Type 2: In this phase, there is interaction between the empty orbital and a π-bond. The most important examples of that are allelic and benzyl systems.
Type 3: The electron pair and an adjacent π-bond will produce allelic or benzyl anions in this structure. In organic chemistry, the focus is not more on the ionic bonds. A look into the reaction levels of the elements and also the reason why they are termed to be so very important.
Type 4 in resonance is one where we have two (or more) π-bonds interacting with each other. This mixture of bonds that we take into consideration is strictly speaking conjugated, for the multiple π-bonds participating in resonance are a “conjugated system” due to their special chemical properties.
RESONANCE STRUCTURE OF NO2–
In this, the bond lengths of both nitrogen-oxygen bonds are equal. The Lewis dots structures tend to represent the different types of bonds in which there will be a combination of nitrogen and oxygen bonds.
We are here to know the formation of these structures so that we can clearly understand the resonance structure. The resonance hybrid of this polyatomic ion, obtained from its different resonance structures, can be used to explain the equal bond lengths.
The reaction process below will explain the elaborate structures as well:
Resonance Structures of NO2- Ion
According to the resonance hybrid of NO2, each oxygen atom holds a partial charge of magnitude ½. Here, the bond length of the N-O bonds is found to be 125 pm. This will help us place the resonance structure of nitrogen.
RESONANCE STRUCTURES OF (Ozone Gas)
This process will explain the formation of ozone gas. In this process, the ozone molecule consists of a central oxygen atom that is singly bonded to one oxygen atom and doubly bonded to another.
There is no one charge that the Lewis structures of this molecule show a +1 charge on the central oxygen and a -1 charge on the singly bonded oxygen. These two are where the resonance structures are to be accumulated; the figure below explains them.
Resonance Structures of O3
In this kind of structure, the resonance hybrid of the ozone gas here has a +1 charge associated with the oxygen, which is at the center, and a partial charge of – (½) associated with the other oxygen atoms.
The structures will also have a definite composition. The resonance theory will help us understand the structure formation of the atoms, and there will be a structural representation for it.
