Fullerenes are a unique form of carbon distinguished by their hollow, cage-like structure.

As a member of the broader category of carbon allotropes, fullerenes stand apart from other forms such as diamond and graphite. Unlike these allotropes, fullerenes consist of carbon atoms that are interconnected to create a hollow structure. This structure can adopt various configurations, with the most recognized being a spherical shape reminiscent of a football. This specific structure is known as buckminsterfullerene, or “buckyball,” which consists of $60$ carbon atoms.

The unique architecture of fullerenes imparts several remarkable properties. One notable characteristic is their ability to encapsulate other atoms or molecules within their hollow structure, a phenomenon referred to as encapsulation. This property has sparked considerable interest in their potential applications in drug delivery systems, where fullerenes could transport therapeutic agents directly to targeted cells or tissues within the body.

Additionally, fullerenes exhibit intriguing electrical properties. Under certain conditions, they can function as superconductors, materials capable of conducting electricity without resistance. This potential has prompted research into their applicability in electronic devices.

In contrast, other carbon allotropes possess different structures and properties. For instance, diamond features a rigid, three-dimensional lattice of carbon atoms, contributing to its exceptional hardness. In contrast, graphite is composed of layers of carbon atoms arranged in hexagonal patterns, which can slide over one another, giving graphite its characteristic softness and lubricity.

In summary, fullerenes represent a distinctive form of carbon characterized by their hollow, cage-like structure, which endows them with properties that differ significantly from those of other carbon allotropes such as diamond and graphite.