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

Diamond Graphite
It has a crystalline lattice. It has a layered structure.
In diamond, each carbon atom is sp3 hybridized and is bonded to four other carbon atoms through a σ bond.  In graphite, each carbon is sp2 hybridized and is bonded to three other carbon atoms through a σ bond. The fourth electron forms a n bond.
It is made up of tetrahedral units. It has a planar geometry.

The C-C bond length in diamond is 154 pm.

The C-C bond length in graphite is 141.5 pm.
It has a rigid covalent bond network which is difficult to break. It is quite soft and its layers can be separated easily.
It acts as an electrical Insulator. It is a good conductor of electricity.