What is the oxidation state of carbon atoms in diamond and graphite?

Oxidation number:

• It represents the number of electrons lost or gained by the atoms of an element in a compound.
• It is usually written with the sign $(+)$ and $(-)$ first and then the magnitude.

Carbon has three main allotropes:

• Diamond: In this, the carbon atom is bonded to four another carbon atoms forming a $3-\mathrm{D}$ structure.
• Graphite: In this, the carbon atom is bonded to three another carbon atoms forming a hexagonal structure.
• Buckminster fullerene: In this, the carbon atom contains a group of $60$ carbon atoms joined together to form a spherical shape.

Carbon exists in pure form in graphite as well as in diamond which means they are present in a free state. The oxidation state of a free state element is zero.

Hence, the oxidation state of carbon atoms in diamond and graphite is zero.