so here we have a sample of barium so
berium is going towards the bottom of
the the group two or alkaline metals so
this is a rod of barium we've got in
here okay so what I'm going to do I'm
going to hopefully if I can get the top
off it's really hard I've got four pairs
of gloves on here um so it's all quite
hard everything's very very difficult to
move I'm have to put it down for a
second barium is a heavy
element I believe that this is a sort of
beum or and it's really heavy piece of
mineral much heavier than you might
expect seeing its
size and um where'd you go that I found
this just lying around when on a walk
somewhere I think it may be be him
sulfate but I'm not a mineralist so I
may be completely wrong but it's a nice
piece and I have it as an ornament in my
office I'm hoping it'll come out aha
there we go
so that's the end of our Rod of barium
so what we can do um it's barium is
quite soft so we should be able to file
a little bit of berium off and we do
that so we have some berium starting
material so we can react it with things
and make berium compounds there it is so
this is 100 G Rod of barium I don't
think we've used too much so they're
probably is close on 100 G there because
barium is a heavy element it has quite
an important medical use because
heavy elements scatter
x-rays so that if you shine x-rays on a
solution or suspension of barium it
looks
black and because the x-rays don't go
through so if you want to take pictures
of the soft part of somebody's body it's
easy to take pictures of their bones but
if you want to look at their gut or
their um throat or their intestin SS
they don't show up on x-rays so you feed
them what is called a Barian meal if
they take it through their mouth or a
barium enema if they take it through the
other end and you pump in quite large
quantities of some barium salt and then
when you X-ray
them the part that's filled up or just
has been coated with it looks black or
white if you look at the X-ray and
negative which people quite often do so
it's very useful for a fairly
straightforward x-ray Imaging of
people's bodies have you ever had a
Barian meal fortunately
not it's not meant to taste very nice I
think they put peppermint or something
into it to pretend that you're enjoying
it but drinking a large quantity of
berium I think is not enormous fun and
people use berium because it's really
non-toxic if you took that amount of
lead or Mercury you might get a better a
picture but you'd be dead so what we
should be able to do hopefully cuz this
barium is soft we should be able to file
a little bit of the barium onto this
foil this is what I'm hoping to do let's
see if I'm a girly girl
now oh I can see little bits coming off
actually they're very very
small so they're very that was a bigger
bit so I'll show you this again in a in
a minute but you can see how we're kind
of starting to clean off the surface so
we're kind of taking that tarnish layer
off many
elements suddenly become fashionable and
in the 1980s late 1980s barium became
fashionable as one of the components of
the so-called high temperature
superconductors a superconductor is a
material which has zero electrical
resistance and people discovered that a
compounds of barium yum and copper
barium yum cuprate and related comp
compounds when they were cooled to
liquid nitrogen
temperature 77° absolute minus 196 CRA
became
superconductors o apart from shaky hands
so I've got hopefully some very sort of
fine barium turnings now so you can see
that okay we have a little bit of
tarnish in there but also they we have
you know quite a shiny Lester as well on
some of the bits
so there's my berium nitrate and again
I'm going to add some of my combustion
mixture
now we're using the energy of that
combustion of the sugar to excite the
barium so that we can observe its
emission spectrum or the flame test
color again pour it out onto a heat
proof
mat so again
so this time again we saw the same
exciting chemical reaction we saw that
same exothermic reaction lots of CO2
lots of steam again but this time the
flame was colored green and this is the
the characteristic apple green which is
associated with barium salts so much
more exciting flame test all the
elements in this group
group two have fluorides that are
insoluble and they're very nice
materials they look like glass and you
can put them in water and they don't
dissolve and this is extremely useful
for technique called infrared
spectroscopy where you're putting
essentially heat Rays through some sort
of liquid to measure the Spectrum how
the light is absorbed and especially if
you're using water or something that's
wet salts of calcium fluoride barium
fluoride are really good for making the
windows here's quite a large window you
can see my eye through it this one
unfortunately is cracked so it's no use
anymore this is calcium fluoride and
calcium fluoride is much cheaper than
barium fluoride so if you can get away
with it you use calcium fluoride for an
experiment the problem is that calcium
ions are quite light
and the fluoride and calcium ions
vibrate in the crystal through thermal
energy and these vibrations absorb
infrared
light barium is much heavier so barium
fluoride vibrates more slowly and so it
absorbs much longer wavelength light so
in a particular experiment if you need
to get that region of a spectrum you
have to go for barium fluoride instead I
tried calling one of my colleagues in
the other office see if you had a piece
of barium fluoride a barium fluoride
window can't find it so you can see
calcium fluoride Barum fluoride will
look exactly the same but honestly makes
us say this is not baring fluoride so we
have this one Big Blob and we have the
finally divided barium as well okay
we're going to try and put that in water
and and see how it reacts
okay so what's happening is we are
seeing um the barium reacting with the
water I think our Big Blob is still
going actually so the barium is reacting
with the water what we're doing is
producing hydrogen gas and what I think
is probably berium
hydroxide um so that's what's
precipitating out of solution