4.1 BONDING IN CARBON – THE COVALENT BOND · Part 4

are known as covalent bonds. Covalently bonded molecules are seen to have strong bonds within the molecule, but inter- molecular forces are weak. This gives rise to the low melting and boiling Figure . Figure . Figure . Figure . Figure . A molecule of hydrogen Figure . Figure . Figure . Figure . Figure . Single bond between two hydrogen atoms These two different structures result in diamond and graphite having very different physical properties even though their chemical properties are the same. Diamond is the hardest substance known while graphite is smooth and slippery. Graphite is also a very good conductor of electricity unlike other non-metals that you studied in the previous Chapter. Diamonds can be synthesised by subjecting pure carbon to very high pressure and temperature. These synthetic diamonds are small but are otherwise indistinguishable from natural diamonds. Fullerenes form another class of carbon allotropes. The first one to be identified was C- which has carbon atoms arranged in the shape of a football. Since this looked like the geodesic dome designed by the US architect Buckminster Fuller, the molecule was named fullerene. The structure of diamond The structure of C- Buckminsterfullerene