| Graphite |
| The word graphite is derived from Greek word 'Grapho' means to write. It is the most stable form of carbon. In graphite carbon is sp2 hybridized. Symmetry is hexagonal. Each carbon atom is linked to three other carbon atoms by covalent bonds to form hexagonal rings. C–C bond length is 1.42 A0. The hexagonal rings form huge sheets or layers, which are held together by weak vander Waal forces. The distance between layers is 3.42 A0. As the distance between layers is very large there are no possibilities of covalent bonds between the layers. Hence fourth valency electron of each carbon atom remains free. |
 |
| Graphite is soft. Density is low. This is because it has layer structure. The distance between layers is very large, which are held together by weak vander Waal forces. It is a good conductor of electricity because it has free electrons. It marks on the paper because different layers of graphite can slide over one another and scales off easily. It is slippery because different layers of graphite are held by weak vander Wall forces and they can slide over one another. It is grayish black, opaque in nature. |
| It is used in making electrodes because it is a good conductor of electricity. It is used in making 'lead' of lead pencils because it marks on paper. Initially graphite was believed to be a black variety of lead, which also marks on paper. So pencils containing graphite are called lead pencils although it has no lead in it. It is used as lubricant because it has slippery nature and non–volatile. It is extensively used as moderator in nuclear reactors because it absorbs neutrons. It is used in the production of crucibles, which can withstand very high temperatures. |
| Previous | Next |
|
