Question

Graphite is anisotropic with respect to conduction of electric current. Explain

Answer 1

Hint: Anisotropy property is exhibited by those solids in which measurement of properties are different along the different directions. The structure of graphite entails hexagonal layers of carbon which are present one over another. The presence of non-bonding electrons is responsible for passing out current from the substance.

Complete answer:
The structure of graphite entails hexagonal layers of carbon atoms which are stacked over one another. Each carbon is covalently bonded to three other carbon atoms. Since carbon is tetravalent, hence each carbon is remaining with one non-bonding electron. The flow of non-bonding electrons is responsible for the flow of electric current. On the other hand, the distance between two hexagonal layers is greater than the carbon-carbon covalent bond. As a result, different arrangements of non-bonding electrons are present in different directions. Hence, measurement of electrical conductivity would be different in different directions which makes graphite anisotropic in nature.
Therefore, Graphite is anisotropic with respect to conduction of electric current because of the presence of different arrangements of non-bonding electrons along the different directions.

Note:
It is important to note that the presence of both weak Van der waals forces of attraction and strong covalent bonds are responsible for getting different arrangement of atoms in the different directions. The movement of non-bonding electrons is responsible for generating electron current. These are the factors responsible for anisotropic character of graphite with respect to conduction of electric current.