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Science

Nanochemistry

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Nanochemistry works with materials at the atomic level and has many potential applications for medical science.

The element carbon comes in different forms or 'allotropes' - three examples are diamond, graphite and Buckminster Fullerene. Their properties make them useful for different purposes.

Carbon

The allotropes of carbon

Three forms (or 'allotropes') of pure carbon are diamond, graphite and buckminster fullerene (or 'buckyballs'). In all three allotropes the carbon atoms are joined by strong covalent bonds but in such different arrangements that the properties of the allotropes are very different.

Diamond

lattice of connected atoms

Diamond

A diamond is one giant molecule of carbon atoms.

Diamonds are colourless and clear (transparent). They sparkle and reflect light – they're lustrous. These properties make them desirable in items of jewellery.

Diamond is extremely hard and has a high melting point. For this reason it's very useful in cutting tools. The cutting edges of discs used to cut bricks and concrete are tipped with diamonds. Heavy-duty drill bits, like those used in the oil exploration industry to drill through rocks, are made with diamonds so that they stay sharp for longer.

Diamond is insoluble in water. It does not conduct electricity.

Higher tier

Every atom in a diamond is bonded to its neighbours by four strong covalent bonds leaving no free electrons and no ions. That's why diamond does not conduct electricity. The bonding also explains the hardness of diamond and its high melting point. A lot of energy would be needed to separate atoms so strongly bonded together.

Graphite

lattice of connected atoms

Graphite

Graphite is formed from carbon atoms in layers.

Graphite is black, shiny and opaque (not transparent). It's also a very slippery material. It's used in pencil leads – it slips easily off the pencil onto the paper and leaves a black mark. It's a component of many lubricants, for example bicycle chain oil. Graphite is insoluble in water. It has a high melting point and is a good conductor of electricity, which makes it a suitable material for the electrodes needed in electrolysis.

Higher tier

Each carbon atom is bonded into its layer with three strong covalent bonds. This leaves each atom with a spare electron, which together form a delocalised ‘sea’ of electrons loosely bonding the layers together. These delocalised electrons can all move along together – making graphite a good electrical conductor. Because the layers are only weakly held together they can easily slip over one another: hence the slipperiness of graphite. Melting graphite is not easy however. It takes a lot of energy to break the strong covalent bonds and separate the carbon atoms.

Buckminster Fullerene

Structure of a buckminsterfullerene molecule - a large ball of 60 atoms

Structure of a buckminsterfullerene molecule - a large ball of 60 atoms

Buckminster Fullerene is one type of fullerene. Fullerenes are made from carbon atoms joined together to make balls, ‘cages’ or tubes of carbon. The molecules of Buckminster Fullerene are spherical and are also known as 'buckyballs' – formula C60.

Buckminster Fullerene is a black solid although it's deep red when in solution in petrol.

The tube fullerenes are called nanotubes which are very strong and are conductors of electricity. Their unusual electrical properties mean that nanotubes are used as semiconductors in electronic circuits. Their strength makes them useful in reinforcing structures where exceptional lightness and strength are needed for example, the frame of a tennis racket. They're also used as a platform for industrial catalysts.

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