Question

Distinguish between structure of diamond and graphite.

Answer 1

• Diamond and graphite, both are crystalline allotropes of carbon.
• In both the allotropes, carbon atoms are linked together by strong covalent bonds displaying different arrangements or structures.
• The difference between the structures of diamond and graphite are given below;

Structure of diamond	Structure of graphite
In diamonds, all four carbon atoms are linked to four other carbon atoms by strong chemical bonds. Thus, forming a tetrahedral structure having one carbon atom at the center and four surrounding carbon atoms at the four corners of the tetrahedron.	In graphite, carbon atoms are linked together to form a layered or sheet-likecentre structure. In each layer, every carbon atom is bonded to three other carbon atoms by strong chemical bonds, thus forming flat hexagonal rings with each hexagonal ring possessing 6 carbon atoms.
The carbon atoms here are ${\mathrm{sp}}^3$hybridized giving rise to the formation of a rigid, three-dimensional structure with strong covalent bonds. This is the reason for diamond being the hardest substance and having high melting point.	The carbon atoms here are ${\mathrm{sp}}^2$ hybridized and the different layers of carbon atoms are attached to each other by weak forces of attraction. This gives graphite a soft and slippery texture and these layers can slip over each other.
All the valence electrons get involved in the valencies bonding, hence they are localized and not free to conduct electricity. This is why, diamond is a poor conductor of electricity.	A carbon atom has four valencies and has the ability to form 4 bonds but, in graphite, a carbon atom is attached to only 3 carbon atoms leaving behind one valence electron which roams around freely inside its crystal structure. This free-moving electron helps in conduction, hence making graphite a good conductor of electricity.
The structure of diamond is given below;	The structure of graphite is given below;