Allotropes of Carbon

The first 200 words of this essay...

Background:

Allotropes are different physical forms of the same element. All elements are made up uniquely of their own atoms and therefore any physical differences must be a consequence of how the atoms are joined together - their arrangement within the bulk structure.

Many elements exhibit allotropy as there are often various ways in which the atoms can be linked together into molecules and also different ways in which the molecules can be arranged to make larger structures.

In the case of carbon, the atoms form either giant macromolecular structures (diamond and graphite) in which all of the atoms in the bulk structure are joined together by covalent bonds making giant molecules, or smaller molecules (Buckminster fullerene) in which there are only discrete molecules made up of 60 carbons in a structure resembling a football (hence the nickname 'bucky balls')

Diamond

Each carbon in a diamond crystal is bonded to four other carbon atoms making a giant macromolecular array (lattice). Each carbon atom has tetrahedral bond angles of 109º 28'.

Physical properties of diamond

* It is very hard, because of all the strong covalent bonds holding the structure together.