Explain the difference in properties of diamond and graphite on the basis of their structures.

Diamond

Graphite

1. Each carbon atom is sp3 hybridised and is bonded to four other carbon atoms by single covalent bonds.

1. In graphite, each carbon atom undergoes sp2 hybridization and is covalently bonded to three other carbon atoms.

2. Diamond has a network structure of a very large number of carbon atoms bonded to each other.

2. The fourth electron in each carbon atoms results in the formation of pi bonds. Thus, it has hexagonal rings in two dimensions.

3. Each carbon atom lies at the tetrahedron and other four carbon atoms are present at the corners of the tetrahedron.

3. The C-covalent distance in rings is 142pm indicating strong bonding. These arrays of rings form layers.

4. C-C bond length is equal to 154pm. Therefore, there is a three-dimensional network of strong covalent in diamond.

4. The layers in graphite are separated by a distance of 340pm. The large distance between these layers indicates that only weak Vander Waals forces hold these layers together.

5. It is very hard and has high melting point.

5. Graphite is soft and the layer's move over one another. Therefore, it is used as a lubricant.

6. It has a bad conductor electricity.

6. It is a good conductor of electricity.