Radicals

Whenever we discuss chemistry, somehow it all comes down to the atom, molecule, and ions, the smallest particles present within the matter. However, these atoms and molecules are composed of electrons, protons and neutrons, so today we will study unpaired electrons called radicals or free radicals. Molecules are made up of two types of electron pairs called bonding electron pairs and lone electron pairs, which are electron pairs that aren’t involved in the bonding process. In these lone pairs, there is an electron sitting alone in one of the orbitals. It is an unpaired electron, and this is referred to as a free radical. In this article, we will examine radicals in-depth and how they are relevant when studying the bonds between molecules and ions.

What is a Radical?

Radicals are molecular types that have an unpaired electron in their atomic orbital, and these electrons are what make radicals highly reactive. As a result of bond breaking, a single covalent bond creates a radical and both of the two species created in the bond-breaking process have an unpaired electron. Several radicals form dimers with similar molecules, and the organic radicals have a short lifetime. Because of the unpaired electrons present in all radicals, they have some characteristics that are common to each other.

Types of Radical Formation

• Homolysis: A free radical is mainly formed when a spin-paired molecule is hemolyzed and two new radicals are formed when the coupling between two molecules is broken, leaving each species with one electron in the covalent bond. In order for homolysis to occur, energy must be present, such as heat or light, because a bond is broken with energy.

A — B → A’ + B’

To indicate that radical species have one unpaired electron, apostrophe commas are placed with them. Radicals possess one unpaired electron and, thus, can form new bonds very quickly because of their high reactivity. Radials can either be electrically neutral, positively charged, known as radical cations, or negatively charged, known as a radical anion.

• Reduction: An electron transfer can occur if a single electron is added to a spin-paired molecule, resulting in radical formation. Generally, a reduction reaction takes place when an alkali metal donates an electron to another spin-paired molecule.

• Abstraction: The process of abstraction refers to the removal of an atom or group from a molecule by a radical, resulting in the production of a newly formed radical and spin-paired molecule. In specific terms, the abstraction of radicals refers to the hydrogen abstraction, which describes the removal of a hydrogen atom from a hydrogen donor molecule with its single electron. An abstraction process does not produce radicals from a single spin-paired molecule in contrast to homolysis, which produces two radicals from a single spin-paired molecule. When we talk about radical chemistry, hydrogen abstraction is one of the most fundamental processes. Carbon radicals are converted into stable molecules during this step since it is the last step in the propagation of many chemical reactions in radical chemistry.

• Addition: An addition of radicals to spin-paired molecules leads to the formation of a new radical. In this radical formation process, the substituent is added to the carbon atom with the least amount of substitution.

• Elimination: Like the opposite of radical addition, radical elimination involves breaking down a radical compound into spin-paired molecules and producing another radical compound.

Properties of Radicals

• It is only possible for radicals to exist under special conditions, so they are rare and unique species, but we are also exposed to free radicals every day.

• Oxygen-free radicals are also involved in immunity, and there are some stable free radicals like nitrogen monoxide.

• Free radicals contain an unpaired electron, thus they have high reactivity and instability, since they may donate electrons to other molecules or accept electrons from other molecules, resulting in them being either oxidants or reactants.

Uses of Radicals

• The free radicals are highly reactive species present in the cells’ membranes at the site of damage to functionally relevant molecules such as DNA, proteins, carbohydrates, and lipids.

• In the presence of free radicals, macromolecules are damaged and their homoeostasis disrupted, for instance, proteins.

Conclusion

A radical is an important element of chemical bonding and plays a role in most of the significant chemical reactions. Free radicals are highly reactive and unstable due to their unpaired electrons. This leads to their exothermic abstraction of hydrogen atoms, necessitating a lot of energy in the form of heat or light energy. We looked at the definition of radicals and types of radical formation in this article. Our discussion focused on the radical formation, which includes homolysis, reduction, abstraction, addition, and elimination. Free radicals are also discussed as well as their characteristics and uses. Overall we can say that we covered all the important aspects of radicals in this article.