Letters - November 2010

Mythbusting

Harold Kroto, Florida State University

It seems timely for me to write about a couple of carbon myths that still find their way into textbooks and should be laid to rest. I would like teachers to be made aware of these.

The first myth is that that graphite is a lubricant because the van der Waals forces between the graphene layers are weak and this allows the sheets to slide over one another. This myth led us to suggest, in 1985, that C₆₀ might be a great lubricant - after all, if graphite is a lubricant then surely round graphite would be super-lubricant. In fact, the first experiment I carried out when I, at last, had a sample of solid C₆₀ in my hands, was to press it with a spatula onto a piece of glass. I was puzzled as it responded just like a lump of grit. I was later informed that graphite is, in fact, not a lubricant in a vacuum when the intercalated gases present in air have been extracted from between the graphene layers. It is for this reason, I understand, that graphite is not used on the Space Shuttle. I was told, and I have no reason to doubt it, that this was discovered during the War (The Second World War rather that the Bush/Blair one). As the bombers and fighter planes went to higher and higher altitudes, the graphite brushes on electric motors became abrasive and wore out quickl