Hello everyone, today I want to tell you about such a metal as tin.
In the periodic table of chemical elements,
tin is in the 14th group among the so-called base metals.
This metal was known back in 4th millennia BC.
Due to the inaccessibility, the price of tin was high.
During the Bronze Age, tin was considered to be a strategic metal,
as the tin-bronze obtained from it is much stronger than pure copper.
Tin is obtained from the minerals of Cassiterite (i.e. tin dioxide),
and from Stannite, that is, tin sulfide.
In its pure form,
tin is a shiny soft metal with a yellowish tinge
due to the tin oxide coloring it.
The density of this metal is slightly less than that of lead,
the melting point being 232 degrees Celsius.
The low melting point of tin makes it possible
to cast different shapes and figures from it.
As an example, the well-known tin soldiers.
And, plus, tin is not toxic like lead.
Also, if you bend an ingot of very pure tin,
you can hear an interesting crunch
caused by the formation of crystals inside the metal.
The same musical property can also be found
in ingots of pure zinc and indium.
They could probably start a band together. (Translator's note: Metallica?)
However, metallic tin, in contrast to other metals,
has one unique property called polymorphism.
The metal that I'm holding in my hand is the beta form of tin (also known as white tin).
If this piece of tin is then put into a cold place,
the temperature of which is below 15 degrees Celsius,
then eventually the white tin
will begin to shift into its grey form,
the so-called alpha form of tin.
In this video, courtesy of the website
you can observe the process of the transition
from white tin to grey,
since grey tin has a completely different crystal structure
similar to the structure of diamond.
Any product made of white tin, with this transformation, will simply fall apart into pieces.
This effect is also called Tin Plague. (Correction: Tin Pest)
This is exactly what happened
with the many collections of tin soldiers due to improper storage.
Also, some historians point to the tin plague (pest)
as one of the circumstances causing Napoleon's ultimate defeat.
The frost lead to the transformation of tin buttons
of the uniforms of soldiers into powder. (Translator's note: this is an unsubstantiated claim)
From the chemical point of view,
tin is a low activity metal that reacts poorly with dilute acids,
but when reacting with Aqua Regia,
tin begins to dissolve actively,
oxidizing to tin tetrachloride,
which is used, for example, in the production of soap.
At temperatures above 115 degrees Celsius,
tin begins to gradually oxidize in air,
but when it's heated to a temperature of about 1000 degrees Celsius,
tin starts burning in air,
forming tin dioxide.
From the tin compounds,
tin(II) chloride is the one most frequently found.
We can also carry out a couple of very beautiful experiments with it.
I dissolved tin chloride in 10% sulfuric acid
to prevent the hydrolysis of tin chloride in water.
Then I poured the solution into a Petrie dish
and attached electrodes to the edges of the cup.
Now with the help of the adaptor,
I'm passing through the solution a constant current of 1 ampere,
and a voltage of 6 volts.
At the same time begins the process
of reduction of tin chloride to beautiful tin crystals at the cathode.
And at the anode, tin is oxidized to tin dioxide.
Tin crystals look very beautiful, especially in microphotography.
By the way, if you change the polarity,
the newly formed tin crystals will begin to dissolve,
as the growth of new crystals will happen
from a negatively charged electrode (i.e. the cathode).
Such a method of reducing tin under
the influence of electricity
is used in the production of tin cans.
If you add a piece of zinc to a solution of tin chloride,
it will begin to get covered with the beautiful tin crystals.
Zinc here will be oxidized to zinc chloride,
and tin will be reduced to metal.
This results in a beautiful tin hedgehog
At the present time,
tin is used mainly as a safe, non-toxic, corrosion-resistant coating in pure form,
or in alloys with other metals.
In ordinary life, we can find tin in
the composition of solder.
Also, tin here comes as a mixture with other metals,
mainly with lead.
The most important alloy of tin is bronze, with copper.
Also, tin is an important alloy component in the production of structural alloys of titanium.
The tin disulfide is used in the composition of paints imitating gold ("jeweled ink").
By the way, in recent years,
because of the introduction of lead-free solder in electronics,
there is now a massive problem:
it also causes tin whiskers,
which is a formation of long and thin tin crystals
grown out of a solder,
which in some bursts is almost pure tin.
These tin whiskers can grow to a decent size,
resulting in a short circuit and equipment failure.
This effect has already lead to a number of failures in electronics,
including a complete breakdown of orbiting satellites.
The exact cause of this effect has not yet been figured out,
however, it can be prevented by the addition of bismuth, antimony
or other low-melting metals to the solder.
Now you know a little bit more about one of the other metals.
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