Carbon: The Element

The element carbon is a nonmetallic chemical substance. It has derived its name from the Latin word "carbo". Carbon is one of the most abundant chemical element in the universe, and it comes fourth after hydrogen, helium and oxygen. In the human body, it is the second most abundant element behind oxygen.

In the periodic table, carbon is positioned in the group 14. Chemically, it is represented by the symbol C. The atomic number of carbon is 6. This means its outermost orbit carries four electrons which can form covalent type of chemical bonds during chemical reactions. Carbon is found in nature in three isotopic forms. Carbon-12 and carbon-13 are stable but carbon-14 is radioactive in nature.

Physical Properties of Diamond and Graphite

Carbon in its atomic form is in a very transient state. Hence, in order to make it stable in multi-atomic structures, it is arranged in a wide variety of molecular configuration called allotrope. Diamond, graphite and amorphous carbon are the most common allotropic forms of carbon. The physical properties of these allotropic forms are very different from each other. While diamond is the hardest of all substances, graphite is a very soft substance. Diamond is transparent but graphite is opaque. Graphite is a good conductor of electricity but diamond is a poor conductor of electricity. Graphite has lubricant properties but diamond is an abrasive.

Compounds of Carbon

The element carbon is capable of forming long chains of carbon-carbon bonds which are strong and stable in nature. This property is known as catenation. Due to this property, compounds of carbon are found in infinite numbers. It is a fact that the number of compounds of carbon are much higher than the compounds of any other element, except hydrogen.

Any organic molecule is made up of hydrocarbons, which can be described as a class of compounds in which hydrogen atoms are bonded with a chain of carbon atoms. The characteristics of an organic molecule depends upon the length of the carbon chain, its side chains and the functional group with which it is associated.

When carbon is bonded with oxygen and hydrogen, a large variety of important biological compounds are formed. They are compounds like carbohydrates, alcohols, fats, esters, carotenoids, etc. Bonding between carbon and nitrogen leads to the formation of alkaloids. Addition of sulfur to carbon bonds give amino acids, antibiotics and rubber products. When phosphorus is added to these other elements they form essential molecules like DNA, RNA (key components of living cells) and ATP (adenosine triphosphate, responsible for transferring of energy in all living cells), which are critical for life.

Those compounds of carbon which are found in minerals and do not have any hydrogen or fluorine content, usually are not formulated as typical organic compounds. Carbon reacts with oxygen to form carbon dioxide. When dissolved in water, it forms a weak acid known as carbonic acid which is unstable in nature. Some other such bonds are carbides, carbonates, cyanides, calcites, etc.

Uses of Carbon

Carbon is a major component of various foods that we eat. Another very important form of carbon is the fossil fuels - coal, petroleum, etc. The uses of element carbon are innumerable. It is used with iron in the manufacturing of various types of alloys. Graphite is used to make the lead that is used in pencils. It is also used as electrodes of dry batteries. It acts as moderators in nuclear reactors. Diamonds are used in making jewelry. It is also used in industries for the purpose of cutting, drilling, grinding, etc. Carbon-14 is a radioisotope of carbon which is used to determine the age of the fossils by the means of a process called radiocarbon dating.

We have already discussed that without carbon compounds, formation of life forms is impossible. However, some of the compounds of carbon are poisonous too. Such compounds are carbon monoxide, tetrodoxotin and cyanides of carbon, etc. If carbon black is inhaled in large quantities, it can cause congestive lung diseases.

Besides being harmful in some forms, the element carbon is very useful to us in many ways and is an important part of life. We are indeed lucky that this chemical element is in abundance in our universe.