Anomalous Behaviour of Carbon

Carbon is one of the most commonly found elements on Earth. It makes for about 0.02 per cent of Earth’s crust and can be found in various compounds throughout the world. Carbon is unique because it has several anomalies in physical and chemical properties. 

Its unusual size, high ionisation energy, and other such structural anomalies make for its many unique characteristics. It is also observed that most carbon compounds have higher melting points and boiling points when compared to other elements from their group (for example, oxygen). Thus, studying the critical differences between carbon and other elements of group 14 of the periodic table is essential. 

Objectives and Functions

When one observes the atomic structure of carbon, we can see that the outermost region of its shell has four electrons. It needs four more electrons to stabilise its final orbit and thus, must obtain it from other sources. 

In order to do this, carbon interacts with other particles in their presence. This leads to the creation of four covalent bonds throughout its life cycle. These four valencies create unique connections which can be studied in detail to understand the anomalous behaviour of carbon notes. 

Catenation

Carbon atoms often bond covalently with other carbon atoms, creating long carbon chains and structures. This process is known as catenation. It has resulted in the creation of several carbon compounds across the surface of Earth. 

This attribute has enabled us to use carbon in organic chemistry and investigate structures built through the catenation process. 

Small size

A small atomic structure characterises carbon. This has enabled carbon atoms to form many bonds easily, especially catenation. Carbon is known as a “half-filled element” because it has four electrons in its outermost orbit, indicating the need to have four more electrons to stabilise its orbit. 

The carbon atom is stable because of its small structure. The nucleus is able to hold not just the bonded electrons but also the free electrons. 

Electronegativity of carbon

Carbon atoms can form p-p bonds with themselves and also with different molecules. This is possible because of the small structure of the carbon atom. It has a high electronegativity, leading to the formation of several bonds like C = C, C = O, C = S, and C = N, among others. 

Presence of allotropes

Due to carbon atoms’ ability to catenate and their ability to form p – p bonds, carbon is able to exhibit several allotropic forms. There are three allotropes of pure carbon: diamond, graphite and buckyballs (buckminsterfullerene). 

In these allotropic forms, carbon atoms are joined with the help of very strong covalent bonds. The arrangement of these covalent bonds is drastically different, leading to very differing properties. 

Diamond

Diamond is a giant molecule composed of carbon atoms. These atoms are colourless and transparent in nature. Upon the reflection of light, diamond atoms sparkle and create a gorgeous spectacle. This is why diamond atoms are often defined as “lustrous”. Today, diamonds are commonly desired as a form of jewellery. 

In addition to its striking appearance, diamond has a very hard texture and a very high melting point. For this purpose, diamonds are also used to cut tools. For example, the edges of discs used to cut concrete and bricks are made of diamond. Diamond is insoluble in water and cannot conduct electricity. This is because all free electrons in the carbon atom are bonded with strong covalent electrons. 

Graphite

Graphite is another unique allotropic form of carbon. The structure of graphite is built through the help of the layering of carbon atoms. In appearance, graphite is black in colour, shiny and opaque. It is often used in pencil leads because it can slide onto paper easily. In addition to pencils, you will find graphite in many industrial lubricants. 

Graphite is also insoluble in water and has a high melting point. However, unlike diamond, graphite is capable of conducting electricity. Thus, graphite rods are often used as electrodes during the chemical process of electrolysis. In graphite, carbon atoms are bonded in layers with the help of three strong covalent bonds, leaving spare electrons. This “sea of electrons” makes graphite a great conductor of electricity. 

Nanotubes of fullerene

Buckminsterfullerene can be found in the nanotubes form. In this form of carbon, molecular-scale tubes of atoms are arranged in layers (like in graphite). These nanotubes have a very high melting point (because of the presence of very strong covalent bonds). 

Each carbon atom bonds with three other carbon atoms through covalent bonds. There are spare electrons here as well, leading to a sea of free electrons. This makes nanotubes a great conductor of electricity as well. 

Unique properties of carbon

• It is interesting to note that the study of carbon and carbon compounds is known as organic chemistry. The prevalence of this element is very high in our surroundings. 

• All living organisms contain carbon.

• Almost 0.03 per cent of the carbon present in our atmosphere is in the form of carbon dioxide. 

• Carbon exists in its free state in the form of diamond, graphite, and fullerenes. Otherwise, it primarily exists in the combined state. Carbon dioxide, carbonates, fossil fuels, wood, cotton, and other organic compounds are some of its many combined forms. 

Conclusion

Carbon is an essential element, the reason behind the very existence of organic chemistry. Its unique physical structure is the reason behind the anomalous behaviour of carbon importance. High electronegativity due to the presence of four free electrons allows carbon atoms to undergo the process of catenation. 

Due to catenation, carbon atoms form different kinds of covalent bonds with each other, leading to the formation of allotropic forms of carbon. These carbon allotropes have various industrial purposes.