Giant covalent structures
2 marks · EasyDiamond has a melting point of about 3550 °C, while C60 fullerene melts at about 280 °C. Use these values to explain, in terms of bonding, why diamond has such a high melting point compared to C60 fullerene.
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Must show: Strong covalent bonds in diamond, Giant structure, Weak intermolecular forces in C60
Also accept: Diamond's atoms are joined by many strong covalent bonds; C60 has weak forces between molecules
Common mistakes: Assuming both have similar bonding
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Marking points
M1 · 1 mark · Identifies that diamond has a giant covalent structure with many strong covalent bonds.
M1 · 1 mark · Identifies that C60 fullerene has weak intermolecular forces between molecules.
Worked solution
Diamond has a giant 3D network of strong covalent bonds between carbon atoms, so a lot of energy is needed to break these bonds and melt it. In C60 fullerene, only weak intermolecular forces hold the molecules together, so it melts at a much lower temperature.