We tend to talk a lot about carbon on this show, because it’s difficult to avoid when
you’re talking about science, or the Earth, or eating, or breathing, or existing in the
universe.
Carbon is a big deal - it’s all around us.
We are carbon-based lifeforms so you’d think we’d have been familiar with all the different
forms, or allotropes, of carbon a long, long time ago.
Well, remarkably recently, in 1985, a team of scientists headed by Harold Kroto, James
R. Heath, and Richard Smalley discovered a new form of carbon.
It was a molecule in the shape of a soccer ball -- or for the rest of the world, a football
-- and they called it buckminsterfullerene, after Richard Buckminster Fuller, the architect
who popularized the geodesic dome.
It’s also called a buckyball, for short.
Chemists call it C60.
Everybody was pretty surprised when the buckyball made its debut, because in the world of organic
chemistry, finding out carbon had an allotrope nobody knew about was a lot like finding out
your dad has a blackbelt in karate and you just didn’t know.
It’s worth mentioning that these guys also got a Nobel Prize in Chemistry for figuring
out how to make a carbon into a soccer ball.
So, how did they do it, and why is it so important?
In the 1980’s, Kroto was investigating some long, flexible chains of carbon that form
clouds in interstellar space, and wanted to look at some of them close up.
The problem was, they were in space and he was on Earth, so he needed to figure out how
to make them himself.
Well, he discovered that Smalley had access to a super powerful laser.
Kroto thought maybe if he shot this laser at some graphite -- layers of carbon arranged
into flat sheets -- he could completely break its carbon-carbon bonds.
Then, the carbon atoms might reorganize themselves into the molecules he wanted to study.
And, Lo and behold!
When Smalley and Kroto tried it, they did find those long carbon chains that they wanted
to make -- but they also found some of the carbon atoms had bonded into this other weird
thing.
It was an extremely stable carbon molecule with 720 protons, which meant it had to be
made of exactly 60 carbon atoms, with 12 protons each.
And it didn’t react easily with other molecules, which is unusual because a single carbon atom
has whopping four spare electrons that it can use to make bonds with other atoms.
The fact that this new molecule wasn’t very reactive meant that each of these 60 carbon
atoms had to have three of their electrons occupied with other carbons, and only one
electron free.
They realized that, for this to be the case, the atoms had to be arranged in some kind
of spherical carbon cage -- kind of like the geodesic dome that Buckminster Fuller had
devised back in 1954.
And just like in a European regulation football, the bonds had to be a mixture of 12 pentagons
and 20 hexagons in order for the cage to close completely.
They’d discovered a brand new form of carbon -- fullerenes, or spherical carbon molecules.
And I say fullerenes, plural, because while C60 and a little C70 were the most common
products of that first experiment, other carbon clusters have since been hypothesized -- and
later proven to exist -- like C76, C78, C84, and so on.
Studying fullerenes for the last 30 years has led us to realize buckyballs are all around
us.
They occur naturally, but sparingly, here on Earth -- you can find them in soot from
a candle or around a place where lightning has struck.
We’ve also figured out that clouds of buckminsterfullerene are pretty common in space--and solid C60
has recently been discovered around a pair of stars 6,500 light years from earth.
But here on this planet, it’s taken a while to get a bead on exactly what C60 can do for
us, especially because it’s very expensive to make even a little bit.
A member of the British House of Lords commented shortly after its discovery, "it does nothing
in particular and does it very well."
Which isn’t totally fair.
Because it does have its uses.
That free electron in each of the carbon atoms gives C60 a lot of flexibility and a high
electrical conductivity.
And even though it’s really soft under normal conditions, C60 can be compressed between
two diamond tips at 320,000 times atmospheric pressure to create a substance so hard it
can dent diamond -- the hardest substance on Earth.
And according to new research published in March, buckyballs might soon find widespread
use -- in medicine.
When a molecule of buckyball is attached to 12 molecules of nitrous oxide, the tiny structure
can explode in a controlled reaction.
Researchers call them buckybombs, and eventually, they could be used in individual cells, to
deliver medication, or to destroy a tumor.
So we may be hearing a lot more about the buckyball in the near future.
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