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hello everyone in this video I am going
to tell you about silicon which can
definitely be called the smartest
element on earth because no calculations
at modern-day devices do would have been
possible with those this metalloid this
may come as a surprise but there is an
abundance of silicon on our planet this
is the second most abundant element
after oxygen however it is incredible
challenging to find pure silicon in
nature because of its property to form
strong chemical bonds with oxygen
forming such a mineral as quartz and
also other silicate minerals pure quartz
crystals which are made of silicon
dioxide have beautiful regular geometric
shapes and have one interesting property
called triboluminescence after up to
quartz crystals against each other you
can see where faint light where the
minerals contact which is a result of
deformation of the crystalline grid of
quartz crystals and the generated energy
is released as heat and light quartz
crystals also have a property called
piezo electricity which you can observe
every time you use a piezo ignition
lighter when a spring-loaded hammer hits
a quartz crystal it causes electric
potential difference which is released
as a spark if there is iron manganese or
other transition metal impurity in
quartz crystal such a violet mineral
will be called a Matiz quartz which
contain water are known as another rare
mineral or pal such stones however are
not found everywhere in contrast to
extremely abundant sand which can be
found practically anywhere in the world
sent as a gift understand is also made
up of silicon dioxide roughly 1/2
percent of iron oxide sand is made up of
gives it its distinctive yellowish hue
because of the very strong
chemical bonds between silicon and
oxygen sand as well as other quartz
minerals is very chemically inert
material and it is extremely challenging
to extract something from it chemically
that is a very reason why pure silicon
was obtained for the first time on in
1923 by reducing potassium floors
silicate with Mountain potassium metal
I'll also try to obtain amorphous
silicon but I'm going to resort to
another methods I'm going to mix one
tenth of a mole of magnesium and 500 of
a mole of fine sand first I decided to
run this reaction in a glass tube
however because of the rapid heat enough
of the mixture is a glass cracked and
its content poured out the neutralizes
at home when I heated up the mixture for
the second time it went much better and
the content didn't pour out in this
reaction
metallic magnesium reduces silicon
dioxide silicon forming so-called
amorphous silicon which looks like a
black sponge this is not a real
effective reaction of extracting
amorphous silicon because the product
obtained as a result of the reaction can
be contaminated by magnesium silicide
besides magnesium is very flammable in
air if we were on the same reaction but
used twice as much magnesium will get
magnesium silicide as a result of such a
violent reaction between sand and
magnesium powder what not world above
the substance is that when it reacts
with a 10% of sulfuric acid the reaction
produces a powerful gasoline which self
ignites when it reacts with air however
this primitive reaction between sand and
magnesium is not used to obtain
amorphous silicon
instead scientists use a reaction
between such a mineral as quartz and
coke in special furnaces the reaction
produces pure silicon however often
times it is not pure enough to be used
for making silicon chips
and in the semiconductors production in
order to obtain even more pure silicon
scientists chlorinate the scrap silicon
which is later reduced with zinc such
silicon is still not fitting for
processors and solar panels yet however
it can be used for a few experiments we
show its chemical properties this
metalloid is quite a resistant of
oxidation in air a piece of silicon
doesn't tarnish and doesn't change even
when it is heated up by a burner its
chemical properties are more similar to
those of boron
however crystalline silicon can react
with a hot alkali solution exhibiting
properties of transition metals for
instance of such a metal as aluminium
this reaction produces sodium metal
silicate and hydrogen if you run the
same reaction but this time with molten
sodium hydroxide the reaction will be
much more violent and produce same
products zero yet another way to purify
is obtained silicon I am using a silicon
powder and grind it even more in a
mortar now I'm mixing it with magnesium
powder then I'm going to heat up this
mixture in a test tube the silicon
begins direct with magnesium producing
magnesium silicide
of higher quality than the reaction
between magnesium and sandjas if we adds
obtained chemical to a 10 percent
sulfuric acid solution the reaction will
produce quite a large amount of porn for
a gas silane and even more oz of silicon
hydrogen compounds when the sealant
bubbles react with oxygen they
immediately explode and burn down in air
producing water and silicon dioxide it
is relative note that the reaction
between Ceylon and oxygen is so stable
that it can be run at the temperature of
liquid oxygen that is at minus 180
degrees Celsius if I run this reaction
in an inert atmosphere and cold
collegues obtains you name I will use it
for produce
hi pure silicone when sealant is heated
to more than 500 degrees Celsius in an
inert atmosphere it breaks down into
hydrogen and pure silicon which is pure
enough to be used in the silicon
semiconductors production you can see
such silicon on the screen you can also
see well that silicon has a
polycrystalline structure which means
that it consists of lots of crystals
which are fused together such silicon is
not fitting for making processors but it
can be used in the production of new
polycrystalline solar cells the thing is
that pure silicon is a semiconductor
this means that electrical resistance
can decrease as a temperature graphs if
we assemble a circuit with a silicon
crystal and connect a small lamp it will
blow quite faintly at room temperature
if we heat a silicon crystal in this
circuit the land will glow much brighter
because of the significant decrease in
the silicon resistance as a higher
temperature this proves that it has
semiconductor properties in case with
irregular conductors zero resistance
drops as the temperature rises because
of its semiconductor properties when
phosphorus is added to the silicon it
becomes a semiconductor which exists
b-type electrons and if there are boron
atoms in the crystalline grid so-called
holes that is errors like an electrons
will form zero there is a so called
depletion zone in between send excess
electrons can jump to where there are
needed prozis zone having overcome the
minimum voltage which is a result of the
depletion zone which thus we can make a
simplest semiconductor device which is
diode but current won't flow in the
opposite direction because of the
electrostatic force solar panels have a
similar design but the upper layer of
the n-type silicon is thinner in order
to make
it possible for light photons to travel
through it when the upper n-type layer
absorbs an electron see depletion zone
releases one electron and the back
electrical contact pushed it back out
again
such voltage is produced as a lower part
of the solar cell is an anode and the
upper is entitled this is how a solar
panel works besides polycrystalline
solar cells there exists another older
type of solar cells which is mono
crystalline - my exam however single
crystals of silicon have to be grown it
is done using the so called tchaikovsky
process a seed crystal rod is dipped
into the molten silicon and slowly
pulled upwards being covered in a new
layers thus turning into a large single
silicon crystal which as well have
organized crystalline grid such a method
of growing crystals resembles from
experiments of growing single crystal of
salt solution but in case with silicon
everything looks far more serious then
such a giant crystal is sliced into
small segments and then they are coated
with oxide layers and hundreds of micro
transistors and PN junctions are
transferred into them later such
segments with a ready-made chips are
soldered to a place-- processor for
smartphones and computers are already if
the pull off such a silicon chip of its
blades polish it then on the opposite
side of it with the help of a microscope
you will be able to see how the micro
transistors are arranged by the way
chips are multicolored because of the
different thickness of the silicon oxide
layer which causes interference of light
nowadays almost all electronic devices
around on silicon semiconductors because
old fashioned germanium semiconductors
are extremely rare these days however
even fro silicon compounds have high
technology applications
they can also be found practically
everywhere they are used in the
production of
illumise indicate building materials
porcelain glass etc as a matter of fact
the houses we live in are about 40% of
silicone minerals some of the hardest
materials on earth are made of silicon
compounds such as silicon nitride and
silicon carbide they are used to make
very hard ceramics which can withstand
high temperatures according to Moore's
scale as a hardness of silicon carbide
is 9.5 that is why it easily scratches
glass and even such a heartless as
Gorilla Glass 4 on your smartphone such
ceramics is used in composite material
bulletproof vests when about it hits
such ceramics it shatters into numerous
beads which are then engulfed by the
other two layers of bulletproof West
also silicon carbide is used to make
abrasive discs for angle grinders
besides in recent times synthetic
moissanite and silicon carbide crystals
have been used more and more of
generally as a cheaper substitute for
diamonds the refractive index and
hardness is almost exactly the same as
that of diamonds that is why
theoretically speaking there is no point
of buying extremely expensive diamonds
anymore it is a lot easier to synthesize
more sunlight crystals also the glass we
have also got used to is made by fusing
together fine sand and sodium carbonate
sand or silicon dioxide content in glass
from 60 to 96%
besides notice pure silicon sphere
waiting around one kilogram and costing
about 1 million euros could have become
a new kilogram standard in 21 century
the sphere is entirely made of silicon
28 isotope the number of atoms in this
sphere is very precise how
in the end of 2018 it was decided to
define one kilogram by the Planck's
constant force the importance of such a
material as silicon should never be
underestimated
without this wonderful polymer some
women's would not be able to achieve
great shapes and success from a chemical
point of view silicon is a launching of
a polymer molecules which consists of
organosilicon chain links viscosity and
properties of silicone polymers depend
on the land of molecules and the degree
of zero binding inside the material for
instance nowadays silicon tubes are
often used in chemistry experiments or
duo or durable materials however when
exposed to high temperatures silicon
tubes as well as other silicones can
burn in air forming a regular silicon
dioxide as a waste material if you liked
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