(a) How can diamonds be made artificially? How do synthetic diamonds differ from the natural one?
(b) Give any two differences between the properties of diamond and graphite. What causes these differences?
(a) Artificial diamonds are made by subjecting pure carbon to extreme temperature and pressure. The diamonds prepared artificially are called synthetic diamonds. Synthetic diamonds differ from natural diamonds in terms of their hardness and brightness. Synthetic diamonds are more bright and less hard than natural diamonds.
|1.||Diamond has a rigid structure that makes it a hard material.||Graphite has a layered structure that makes it a soft material.|
|2.||Diamond does not conduct electricity.||Graphite is a good conductor of electricity.|
The differences in their properties are due to the different arrangement of carbon atoms in both the allotropes. In diamond, one carbon atom is linked to four other carbon atoms by strong covalent bonds to form a regular tetrahedron. While in graphite, one carbon atom is joined to three other carbon atoms by covalent bonds to form a flat hexagonal ring. In graphite, the various layer of carbon atoms is held together by a weak van der Waals force.
Graphite is a good conductor, as in its crystal, only three valence electrons of a carbon atom are used in the bond formation, while the fourth valence electron is free. The free movement of these electrons in the graphite crystal allows the conductivity of electric current.