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It should be alright! There it goes! Aww, actually that’s quite
spectacular at the end.
And in my second-year, I think I love boron far too much I think,
‘cause I talk about it too much.
You love boron?
I love boron! No, I used to do lots of chemistry with boron, I
kind of moved away a little bit from boron now but I really
like it.
Boron is an interesting element. It is one of the few that I
have actually made myself when I was at school.
Boron sits on top of the group 13. Its atomic number is 5, so
it is a metalloid, so elemental boron is a metalloid which
basically means that it has some of the properties of a non
metal and some of the properties of a metal.
I mixed an oxide of boron with magnesium, heated it up and
then, it is a really dramatic reaction when you add water at
the end to try and destroy the magnesium boride that has
formed because you get puffs of gas coming off which burst
into flames rather like little anti-aircraft guns. But boron itself
was rather disappointing; it’s a sort of brown powder.
I mean there is a more of a powdery brown boron, there are
several crystalline sort of types of alatropes of boron. There is
one actually that is really, really hard, so the black crystalline
boron is actually very, very hard. It’s just below diamond on
Mohs scale of hardness, so I believe. And actually in America,
there is a town called Boron. It’s in California, it’s got a
population of around 2000 which actually was set up around
the world’s biggest borax mine which is in California.
Well it used to be transported on trains of mules and the
company that produced it used to have as their trademark a
train of 20 mules sort of going along.
Of great interest to us chemists, well over the last sort of 50,
maybe sort of 60-70 years, have been the boron hydrides or
borades. So boron hydrides are basically clusters of borons
with hydrogens around them. And one of particular use and
interest in the 50s was one called pentaborane, which
basically: penta, five, it’s got five borons in it. And
Pentaborate was investigated during the cold war or in the
early part of the cold war as being a rocket fuel. It actually
burns with a green flame. They actually called it the ‘green
dragon’ because it burns with a very, very hot green flame
and also because it is pretty toxic, which I can actually show
you if I … It is probably not going to be spectacular.
And boron complexes or borax compounds are used in a
variety of things. It is not a particularly expensive material. It
is used in washing powder, particularly perborate which when
you heat it up in the washing machine when the water gets to
60 degrees centigrade it turns into hydrogen peroxide which
can then bleach the clothes and this is why the famous
washing powder is called Persil, because the ‘per’ stands for
perborate and the ‘sil’ stands for silicate so it is really a
mixture of perborate and silicate.
Ok so this isn’t pentaborane because pentaborane spontaneously combusts in the air. This is
just benzene boronic acid. It’s an organic compound with
some boron in it. So hopefully we can see, we should be able
to see, if I can get some at the end of my spatula, that it
should be able to burn with some sort of green flame. Hey, there
it is. You can also see a bit of yellow which is the organic
bit going as well. It should be alright! There it goes! Aww,
actually that was quite spectacular at the end. Ok.