1
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It should be alright! There it goes! Aww,
actually that’s quite

2
00:00:04,600 --> 00:00:06,210
spectacular at the end.

3
00:00:06,210 --> 00:00:10,550
And in my second-year, I think I love boron
far too much I think,

4
00:00:10,550 --> 00:00:12,750
‘cause I talk about it too much.

5
00:00:12,750 --> 00:00:14,599
You love boron?

6
00:00:14,599 --> 00:00:17,000
I love boron! No, I used to do lots of chemistry
with boron, I

7
00:00:17,000 --> 00:00:20,150
kind of moved away a little bit from boron
now but I really

8
00:00:20,150 --> 00:00:20,710
like it.

9
00:00:20,710 --> 00:00:25,609
Boron is an interesting element. It is one
of the few that I

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00:00:25,609 --> 00:00:28,260
have actually made myself when I was at school.

11
00:00:28,260 --> 00:00:32,019
Boron sits on top of the group 13. Its atomic
number is 5, so

12
00:00:32,019 --> 00:00:35,300
it is a metalloid, so elemental boron is a
metalloid which

13
00:00:35,300 --> 00:00:37,630
basically means that it has some of the properties
of a non

14
00:00:37,630 --> 00:00:39,820
metal and some of the properties of a metal.

15
00:00:39,820 --> 00:00:45,910
I mixed an oxide of boron with magnesium,
heated it up and

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00:00:45,910 --> 00:00:51,399
then, it is a really dramatic reaction when
you add water at

17
00:00:51,399 --> 00:00:56,489
the end to try and destroy the magnesium boride
that has

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00:00:56,489 --> 00:01:00,399
formed because you get puffs of gas coming
off which burst

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into flames rather like little anti-aircraft
guns. But boron itself

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was rather disappointing; it’s a sort of
brown powder.

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00:01:08,799 --> 00:01:11,490
I mean there is a more of a powdery brown
boron, there are

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several crystalline sort of types of alatropes
of boron. There is

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one actually that is really, really hard,
so the black crystalline

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00:01:17,060 --> 00:01:20,840
boron is actually very, very hard. It’s
just below diamond on

25
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Mohs scale of hardness, so I believe. And
actually in America,

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there is a town called Boron. It’s in California,
it’s got a

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population of around 2000 which actually was
set up around

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00:01:32,119 --> 00:01:34,270
the world’s biggest borax mine which is
in California.

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00:01:34,270 --> 00:01:40,930
Well it used to be transported on trains of
mules and the

30
00:01:40,930 --> 00:01:47,930
company that produced it used to have as their
trademark a

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00:01:49,590 --> 00:01:52,450
train of 20 mules sort of going along.

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00:01:52,450 --> 00:01:56,450
Of great interest to us chemists, well over
the last sort of 50,

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00:01:56,450 --> 00:01:59,740
maybe sort of 60-70 years, have been the boron
hydrides or

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00:01:59,740 --> 00:02:04,880
borades. So boron hydrides are basically clusters
of borons

35
00:02:04,880 --> 00:02:08,860
with hydrogens around them. And one of particular
use and

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interest in the 50s was one called pentaborane,
which

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basically: penta, five, it’s got five borons
in it. And

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Pentaborate was investigated during the cold
war or in the

39
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early part of the cold war as being a rocket
fuel. It actually

40
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burns with a green flame. They actually called
it the ‘green

41
00:02:28,180 --> 00:02:31,500
dragon’ because it burns with a very, very
hot green flame

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00:02:31,500 --> 00:02:34,569
and also because it is pretty toxic, which
I can actually show

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00:02:34,569 --> 00:02:41,170
you if I … It is probably not going to be
spectacular.

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00:02:41,170 --> 00:02:46,920
And boron complexes or borax compounds are
used in a

45
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variety of things. It is not a particularly
expensive material. It

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00:02:49,610 --> 00:02:53,250
is used in washing powder, particularly perborate
which when

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00:02:53,250 --> 00:02:58,730
you heat it up in the washing machine when
the water gets to

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00:02:58,730 --> 00:03:02,580
60 degrees centigrade it turns into hydrogen
peroxide which

49
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can then bleach the clothes and this is why
the famous

50
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washing powder is called Persil, because the
‘per’ stands for

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00:03:12,580 --> 00:03:16,560
perborate and the ‘sil’ stands for silicate
so it is really a

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mixture of perborate and silicate.

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00:03:18,959 --> 00:03:24,720
Ok so this isn’t pentaborane because pentaborane
spontaneously combusts in the air. This is

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just benzene
boronic acid. It’s an organic compound with

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some boron in it.
So hopefully we can see, we should be able

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to see, if I can
get some at the end of my spatula, that it

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should be able to
burn with some sort of green flame. Hey, there

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it is. You can
also see a bit of yellow which is the organic

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bit going as well.
It should be alright! There it goes! Aww,

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actually that was
quite spectacular at the end. Ok.