Chemistry - Carbon

Introduction

• Carbon is a non-metallic and tetravalent element.

• Tetravalent means – carbon makes four electrons available to form the covalent chemical bonds.

• Carbon has three isotopes that occur naturally – namely ¹²C, ¹³C, and ¹⁴C.

• Among them, ¹²C and ¹³C are stable, but ¹⁴C is a radioactive isotope. Half-life of ¹⁴C is about 5,730 years.

Salient Features of Carbon

• The physical properties of carbon largely depend on its allotropes.

• Major allotropes of carbon are graphite, diamond, and amorphous carbon.

• Graphite is opaque, black, and very soft; hence, it used to form a streak on the paper.

• Diamond very hard (the hardest naturally occurring material) and transparent.

• Graphite is a good conductor of electricity.

• Diamond is bad conductor of electricity.

• Carbon most likely has the highest sublimation point among all the elements.

Occurrence of Carbon

• In terms of mass, carbon is the fourth most abundant chemical element found in the universe (after hydrogen, helium, and oxygen).

• Carbon is available in abundance in the Sun, stars, comets, and in the atmospheres of most of the planets.

• Carbon is found in the earth’s atmosphere and dissolved in water.

• Hydrocarbons, such as coal, petroleum, and natural gas, all of them contain carbon.

• Carbon is also found in methane hydrates, which found in polar regions and under the seas.

• Some of the rocks enriched of carbon are coal, limestone, dolomite, etc.

• Coal is very rich in carbon; hence, it is the largest commercial source of mineral carbon.

• Coal shares about 4,000 gigatonnes or 80% of total fossil fuel.

Compounds of Carbon

• Following are the major compounds of Carbon −

  • Cyanogen - CN₂

  • Hydrogen cyanide - HCN

  • Cyanamide - CN₂H₂

  • Isocyanic acid - HNCO

  • Cyanogen chloride - CNCl

  • Chlorosulfonyl isocyanate - CNClO₃S

  • Cyanuric chloride - NCCl₃

  • Carbon disulfide - CS₂

  • Carbonyl sulfide - OCS

  • Carbon monosulfide - CS

Uses of Carbon

• Depending upon the allotrops, carbon is used in range of applications.

• Carbon is one of the most essential elements of life without it, we cannot imagine life on the earth.

• The fossil fuel namely methane gas and crude oil (petroleum), coal etc. are used in everyday life.

• Graphite, combining with clay, used in making 'lead' used in pencils.

• Charcoal is also used as a drawing material in artwork, iron smelting, barbecue grilling, etc.

• Diamond is usually used in jewelry.

• Industrial diamonds are used in cutting, drilling, and polishing tools for machining the metals and stone.

• Fossil hydrocarbons, and carbon fiber are used in making plastic.