What are the structures of graphite and carbon fibers, and what can they tell us?
The atomic structure of graphite has been determined by x-ray diffraction and other analytical techniques and is shown in Figure 3.18. Parallel sheets of hexagonal rings are spaced 3.35 apart. Bonds within the chickenwire-like sheets are very strong, but interactions between the sheets are weaker and can be broken easily. Given this atomic arrangement, we can begin to explain some of the properties of graphite. When the interactions between sheets break, the planes slide over one another. It is this sliding that makes graphite such a good lubricant, and also explains why it is a soft brittle substance. Figure 3.18 Structure of graphite The great stability of graphite can be explained in terms of its bonding. From the interlocking hexagonal rings we see that each carbon is bonded to three other carbon atoms. We know that the bonding rules for carbon call for a total of four bonds. This suggests that there are two single and one double bond from each carbon. It is observed from the x-ray
