Describe the differences in molecular structure between graphite and diamond, and use this to explain their differing properties.

Both graphite and diamond are made of carbon atoms. However, while the carbon atoms in diamond are bonded to four neighbouring atoms, the carbon atoms in graphite are only bonded to three other atoms. The final un-bonded outer shell electron of the carbon in graphite is delocalised (shared among all the atoms). Diamond has a giant covalent structure, whereas graphite is formed of sheets of carbons atoms stacked on top of each other with a ‘cushion’ of delocalised electrons in between the layers.Diamond cannot conduct electricity whereas graphite can. This is because graphite has delocalised electrons which are able to move freely through the substance, but in diamond all the electrons are firmly fixed in place in bonds. Also, diamond is an extremely hard substance due to the immovable covalent bonds, whereas in graphite the layers of carbon atoms can slide over each other on the delocalised electrons.