Carbon is in the IV-A group of the periodic table. It belongs to the non-metallic categories of elements. Carbon is the 14th most abundant element in the world. Only 0.08 percent of earth's crust in the form of carbon and about half of this is in the form of the carbonates. Most abundant is calcium carbonate in its various form chalk, lime stone, marble, etc. in addition, it is found as dolomite and as the magnesium carbonate. Carbon is also found in the air and in the sea in the form of carbon dioxide. All living matter is composed of water and compounds of carbon. So far millions of the carbon compounds have already been discovered and their number is increasing day by day. Carbon is an essential constituent of all the organic compounds, for example, the petrol, oil, the hydrocarbons etc. about two hundred years ago chemists divided the compounds into the two groups. The compounds of carbon are obtained from plants and animals' origins were called organic compounds, and those compounds which are obtained from mineral were called inorganic compounds. Carbon occurs naturally in the two states. One is Crystalline (graphite, diamond) form and the other is amorphous (coal, charcoal) form.
