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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