Hello everyone. In this video, I would like to tell you about such an unusual element as antimony.
This element belongs to group 15,
and to the so-called semimetal series in the periodic table of chemical elements.
From a chemical point of view, antimony is rather a metal.
It means that it easily oxidizes, or in other words
it gives its electrons - and it even looks like a metal.
Metallic antimony is silvery, and can easily be confused with bismuth.
However, in contrast to other metals that are good heat and electricity conductors,
antimony doesn't conduct electricity well.
Because of such a property, it was added into the nonmetals.
Nevertheless, antimony as an element should not be confused with stibnite,
that is its natural mineral: antimony trisulfide.
Since ancient times, women have used stibnite in powdered form
to darken the eyebrows and eyelashes.
Because of that, the word antimony is often associated with cosmetics.
Of course, nowadays, antimony trisulfide is rarely used in cosmetics
because antimony compounds are toxic to people.
For instance, now antimony trisulfide is used to make match heads.
It is stibnite that antimony is extracted from
by melting of the mineral with further reduction of the oxide.
to the elementary antimony.
The piece of antimony you see on your screen is the metallic form of this element.
From a physical point of view, antimony is pretty fragile.
It can be easily crumbled, and even be turned to a powder in a mortar.
Metallic antimony's melting point is pretty low - 640 degrees Centigrade.
If heated up at even higher temperatures, antimony can evaporate
and turn into a black modification.
As you can see, the lid has covered in a black soot of antimony
that has quickly condensed on the surface of the lid.
Black antimony is more chemically active,
and easily oxidizes into antimony trioxide when it comes into reaction with air.
Besides metallic and black antimony, there is yet another very unusual form of this element:
so-called explosive antimony.
It looks like a glass-like substance.
If a piece of such antimony is thrown at a stone or heated up,
it may explode, making a loud noise and turning into regular antimony.
From a chemical point of view, antimony is quite an active element.
If powdered antimony is poured into a flask filled with chlorine,
a chemical reaction will start on its own.
Antimony self-ignites in a chlorine environment, forming antimony chloride.
Antimony pentachloride is a thick liquid that is used in organic synthesis for chlorinating different compounds.
When exposed to air, it breaks down into antimony trioxide and hydrogen chloride
that looks like smoke.
Almost all antimony compounds are toxic to people,
although, not as toxic as arsenic, for instance.
Also, antimony reacts well with acids.
For instance, with concentrated nitric acid it forms antimony pentoxide
and nitrogen dioxide.
This element dissolves well in aqua regia, forming antimony trichloride,
which is used as a flame-retardant agent for some types of plastic that doesn't burn well.
Lots of mobile phones' plastic cases contain it.
Pure antimony is a part of a lead alloy.
Today, this alloy is irreplaceable when it comes to car lead acid batteries' production.
Adding antimony to the allow improves its casting properties,
and also improves batteries' life.
Besides that, antimony also forms intermetallic compounds -
that is - two covalent bonds between two metals.
For instance, indium and antimony intermetallic compound is used
is used in infrared detectors.
To sum up, we can say that antimony is pretty toxic but still very unusual element,
having lots of modern-day applications.
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