What are the 5 allotropes of carbon?

The five allotropes of carbon are diamond, graphite, fullerenes, nanotubes, and graphene. Diamond features a tetrahedral lattice structure, making it extremely hard. Graphite consists of layers of hexagonally arranged carbon atoms, allowing for lubricating properties. Fullerenes are spherical or tubular structures, while graphene is a single layer of carbon atoms arranged in a two-dimensional honeycomb lattice.