Celebrating 22 Years on the Web
Find science on or your birthday


Stories About Chemistry


94. An Adamantine Heart and the Hide of a Rhinoceros

There is a class of compounds in organic chemistry called hydrocarbons. And that is just what they are, because their molecules contain hydrogen and carbon atoms, and nothing else. Their best known typical representatives are methane (constituting about 95 per cent of natural gas) and petroleum, from which various grades of petrol, lubricants, and many other valuable products are made.

Take the simplest hydrocarbon, methane CH4. Now if we replace the hydrogen atoms in methane by oxygen atoms, what do we get? Carbon dioxide CO2. And if we replace them by sulphur atoms? A volatile poisonous liquid called carbon disulphide CS2. If we replace all the hydrogen atoms by chlorine atoms, we also get a well-known substance, carbon tetrachloride. But what if we take fluorine instead of chlorine?

About three decades ago hardly anybody could answer this question intelligibly. But in our time the chemistry of fluorocarbon compounds is already an independent branch of chemistry.

In physical properties fluorocarbons are almost complete analogues of hydrocarbons. But that is as far as their common properties go. In contrast to hydrocarbons, fluorocarbons are very unreactive substances. Besides, they are very resistant to heat. That is why they are sometimes called substances with “an adamantine heart and the hide of a rhinoceros.”

The chemical explanation for their stability compared to hydrocarbons (and other classes of organic compounds as well) is relatively simple. Fluorine atoms are much larger than hydrogen atoms and therefore render the carbon atoms they surround inaccessible to other reactive atoms.

On the other hand, fluorine atoms transformed into ions are very reluctant to yield their elections and “dislike” to react with any other atoms. Fluorine, as we know, is the most active nonmetal, and there is practically no other nonmetal which can oxidize its ion (i.e., remove an electron from it). Again, the carbon-carbon bond is itself very stable (remember diamond).

Owing to their inertness fluorocarbons have found a wide range of applications. For instance, fluorocarbon resins called Teflon can withstand heating to 300°C and are indifferent to sulphuric, nitric, hydrochloric and other acids. They resist boiling alkalis and are insoluble in all known organic and inorganic solvents.

Not for nothing are fluoroplastics sometimes called “organic platinum”: they are splendid materials for making chemical laboratory ware, various industrial chemical equipment, and pipes for a great variety of purposes. Believe us, very many things in this world would be made of platinum, were it not so expensive, but fluoroplastics are comparatively cheap.

Fluoroplastics are the most slippery substances in the world. A fluoroplastic film thrown on a table will literally “flow off” it on to the floor.

Bearings made of fluoroplastics require practically no lubrication. Finally, fluoroplastics are excellent dielectrics and very heat-resistant ones too. Fluoroplastic insulation can withstand heating to 400°C, which is above the melting point of lead!

Such are fluoroplastics, which are among the most remarkable man-made materials.

Liquid fluorocarbons are noncombustible and freeze at very low temperatures. These compounds are not attacked by fungi or insects, and are very resistant to corrosion.

< back     next >

- 100 -
Sophie Germain
Gertrude Elion
Ernest Rutherford
James Chadwick
Marcel Proust
William Harvey
Johann Goethe
John Keynes
Carl Gauss
Paul Feyerabend
- 90 -
Antoine Lavoisier
Lise Meitner
Charles Babbage
Ibn Khaldun
Ralph Emerson
Robert Bunsen
Frederick Banting
Andre Ampere
Winston Churchill
- 80 -
John Locke
Bronislaw Malinowski
Thomas Huxley
Alessandro Volta
Erwin Schrodinger
Wilhelm Roentgen
Louis Pasteur
Bertrand Russell
Jean Lamarck
- 70 -
Samuel Morse
John Wheeler
Nicolaus Copernicus
Robert Fulton
Pierre Laplace
Humphry Davy
Thomas Edison
Lord Kelvin
Theodore Roosevelt
Carolus Linnaeus
- 60 -
Francis Galton
Linus Pauling
Immanuel Kant
Martin Fischer
Robert Boyle
Karl Popper
Paul Dirac
James Watson
William Shakespeare
- 50 -
Stephen Hawking
Niels Bohr
Nikola Tesla
Rachel Carson
Max Planck
Henry Adams
Richard Dawkins
Werner Heisenberg
Alfred Wegener
John Dalton
- 40 -
Pierre Fermat
Edward Wilson
Johannes Kepler
Gustave Eiffel
Giordano Bruno
JJ Thomson
Thomas Kuhn
Leonardo DaVinci
David Hume
- 30 -
Andreas Vesalius
Rudolf Virchow
Richard Feynman
James Hutton
Alexander Fleming
Emile Durkheim
Benjamin Franklin
Robert Oppenheimer
Robert Hooke
Charles Kettering
- 20 -
Carl Sagan
James Maxwell
Marie Curie
Rene Descartes
Francis Crick
Michael Faraday
Srinivasa Ramanujan
Francis Bacon
Galileo Galilei
- 10 -
John Watson
Rosalind Franklin
Michio Kaku
Isaac Asimov
Charles Darwin
Sigmund Freud
Albert Einstein
Florence Nightingale
Isaac Newton

by Ian Ellis
who invites your feedback
Thank you for sharing.
Today in Science History
Sign up for Newsletter
with quiz, quotes and more.