7) Allotropes of Carbon

Diamond — Very Hard

1. Diamond has a giant covalent structure made entirely of carbon atoms, each forming four covalent bonds. This makes diamond extremely hard.

2. These strong covalent bonds require a lot of energy to break, so diamond has a very high melting point.

3. Diamond does not conduct electricity because there are no free electrons or ions.

Graphite — Contains Sheets of Hexagons

1. In graphite, each carbon atom forms three covalent bonds, creating layers of carbon atoms arranged in hexagons.

2. There are no covalent bonds between the layers, only weak forces, allowing the layers to slide over each other. This makes graphite soft and slippery, perfect for use as a lubricant.

3. Graphite also has a high melting point due to the strong covalent bonds within the layers.

Graphene — One Layer of Graphite

1. Graphene is a single layer of carbon atoms arranged in hexagons.

2. It is just one atom thick, making it a two-dimensional substance.

3. The network of covalent bonds makes it very strong and incredibly light, so it can be added to composite materials to improve strength without adding much weight.

4. Like graphite, graphene contains delocalised electrons, meaning it can conduct electricity. It has potential applications in electronics.

Fullerenes — Form Spheres and Tubes

1. Fullerenes are molecules of carbon shaped like closed tubes or hollow balls. A famous example is Buckminsterfullerene, which has the molecular formula C₆₀ and forms a hollow sphere.

2. Fullerenes can be made of carbon atoms arranged in hexagons, pentagons, or heptagons.

3. They can be used to trap other molecules, like delivering drugs into the body, by encasing the molecules inside the fullerene structure.

4. Fullerenes have a large surface area, making them useful in industrial processes, like acting as catalysts or as lubricants.

5. Fullerenes can form nanotubes, which are tiny carbon cylinders. Nanotubes are strong and can conduct both electricity and thermal energy.

6. Nanotechnology involves using nanotubes in electronics or to strengthen materials without adding weight.