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Chapter: 9th Science : Carbon and its Compounds

Discovery of Carbon-Milestones

Carbon has been known since ancient times in the form of soot, charcoal, graphite and diamonds. Ancient cultures did not realize, of course, that these substances were different forms of the same element.

Discovery of Carbon-Milestones

Carbon has been known since ancient times in the form of soot, charcoal, graphite and diamonds. Ancient cultures did not realize, of course, that these substances were different forms of the same element.

In 1772, French scientist Antoine Lavoisier pooled resources with other chemists to buy a diamond, which they placed in a closed glass jar. They focused the Sun’s rays on the diamond with a remarkable giant magnifying glass and saw the diamond burn and disappear. Lavoisier noted that the overall weight of the jar was unchanged and that when it burned, the diamond had combined with oxygen to form carbon dioxide. He concluded that diamond and charcoal were made of the same element – carbon.

In 1779, Swedish scientist Carl Scheele showed that graphite burned to form carbon dioxide and so it must be another form of carbon.

In 1796, English chemist Smithson Tennant established that diamond is pure carbon and not a compound of carbon and it burned to form only carbon dioxide. Tennant also proved that when equal weights of charcoal and diamonds were burned, they produced the same amount of carbon dioxide.

In 1855, English chemist Benjamin Brodie produced pure graphite from carbon, proving graphite is a form of carbon.

Although it had been previously attempted without success, in 1955 American scientist Francis Bundy and co-workers at 'General Electric' company finally demonstrated that graphite could be transformed into diamond at high temperature and high pressure.

In 1985, Robert Curl, Harry Kroto and Richard Smalley discovered fullerenes, a new form of carbon in which the atoms are arranged in soccer-ball shapes. The most recently discovered allotrope of carbon is graphene, which consists of a single layer of carbon atoms arranged in hexagons. Graphene’s discovery was announced in 2004 by Kostya Novoselov and Andre Geim, who used adhesive tape to detach a single layer of atoms from graphite to produce the new allotrope. If these layers were stacked upon one other, graphite would be the result. Graphene has a thickness of just one atom.

 

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