Both diamond and graphite are forms of carbon, but they have different structures and properties due to the arrangement of carbon atoms.

Diamond is a giant covalent structure that is formed from the element carbon. Each carbon atom is covalently bonded to four other carbon atoms, which forms a tetrahedral structure.

3D illustration of the diamond crystal structure. Dark brown spheres represent carbon atoms, interconnected by straight white lines indicating covalent bonds. Each carbon atom is bonded to four others, forming a tetrahedral arrangement. Accompanying text reads: 'In the diamond structure, each carbon atom forms four covalent bonds with four other carbon atoms to form a tetrahedral structure'.

With a greater number of carbon atoms, it would look something like this:

Illustration of the crystal lattice structure of a diamond. Dark grey spheres represent carbon atoms, interconnected by straight grey lines indicating covalent bonds in a three-dimensional network. The word 'Diamond' is displayed below the structure.

Properties and Uses of Diamond

To understand why diamond has certain properties, it’s important to first understand its composition. Diamond is made up of a large number of carbon atoms that are held together by strong covalent bonds. These covalent bonds require a significant amount of energy to be broken, which is why diamond has a high melting and boiling point.

One of the key features of diamond is that it does not conduct electricity. This is because there are no free (delocalised) electrons that can carry electrical charge.

However, the strong covalent bonds in diamond also make it extremely hard and durable. This is why diamond is so useful for cutting glass and drilling rocks. Diamond is also used in jewellery and to coat blades in cutting tools.