Chemistry in everyday life involves chemical reaction which we can see, like cooking and experiments at school using test tubes. However, the chemical changes take place on particle level and there are millions and billions of these involved in every chemical reaction.
Nanochemistry deals with individual particles, i.e. on an atom level. It is possible to arrange atoms inside an element in a different way and create allotropes of the same element. For example, diamond, graphite and fullerenes are all allotropes of carbon.
Diamond is the hardest substance that exists and is used in jewellery and the manufacturing and building industries, in cutting tools. Diamonds have a high melting point, do not conduct electricity and are insoluble in water. Jewellery diamonds are almost colourless, clear and shiny, but industrial ones are coloured and opaque. Each atom is held by covalent bonds to four other atoms, which in turn are bonded to more and so on. They form a giant structure and the covalent bonds are incredibly strong, so the melting point is very high. The picture below shows a model of the diamond structure:
Graphite is also made of carbon, but it is soft, opaque and black (but still shiny). It is also insoluble in water, but conducts electricity very well. Its melting point is high, so it can be used to make electrodes for electrolysis. It is made of flat layers that are far apart, and this makes it slippery, so it can be used to make pencils. When you write with a pencil, some of the graphite slides off and leaves the mark on the paper, due to this property. Look at the diagram below to see how different graphite's structure is to that of diamond:
Fullerenes, also made of carbon, look very different to both graphite and diamond. Have a look at the model of fullerenes:
Fullerenes are black solids, insoluble in water, but soluble in petrol. They are used to carry drug molecules around the body, and trap and remove dangerous substances from the body. Their nanotubes are used in catalyst systems.