Define allotropy. Write the different allotropic forms of carbon.

Allotropy is the property of an element to exist in two or more different physical forms in the same state. Carbon shows allotropy in forms such as diamond, graphite, and fullerene. Some elements in nature can exist in more than one physical form even though they are made of the same kind of atoms. This phenomenon is called allotropy. The difference in forms arises due to how the atoms are arranged or bonded.

Allotropy in Carbon

Carbon is one of the best-known examples of allotropy. Its atoms can bond in different ways, giving rise to unique structures and properties. The major allotropic forms of carbon are:

Main Allotropes of Carbon

• Diamond – Each carbon atom is bonded to four other atoms in a 3D structure. It is the hardest natural substance, transparent, and a poor conductor of electricity.
• Graphite – Carbon atoms are arranged in layers, each atom bonded to three others. Layers can slide over each other, making graphite soft and slippery. It conducts electricity.
• Fullerenes – Molecules shaped like spheres or tubes (e.g., buckminsterfullerene, C60). They have interesting properties used in nanotechnology.
• Amorphous Carbon – Includes forms like charcoal, coal, and soot. Atoms lack a fixed arrangement.

Comparison of Major Carbon Allotropes