Some allotropes of carbon

So-called buckminsterfullerenes ( buckyballs ), only identified in the 1990s, are the manifestation of carbon atoms joined in yet a different way. As shown in Figme 1.2 an individual bucky ball comprises 60 or 70 carbon atoms linked through a series of pentagons and hexagons in a structure shaped like a soccer ball. These substances can act as superconductors but their range of applications has yet to be determined. 

Finally, in the late 1960s, a fifth allotrope of carbon was created in the laboratory. This substance is transparent and is produced at low pressure from graphite. Called white carbon , it is crystalline and birefringent, i.e. it can split a beam of polarised light in two. 

Apart from its chemical ubiquity, carbon can adopt many structural forms, as discussed in Section 1.1 above. These allotropes of carbon are possible because of the varied ways carbon can combine with itself. Such substances cannot, however, be described as organic as they are the products of geological rather than biological processes. Nevertheless they remain important in terms of human and environmental history because they have industrial and social uses and so are components of wealth generation. 

Carbon is chemically reactive and can combine with many other elements to produce simple and complex compounds. Some of these are 

---