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Hello, everyone. Today I'll tell you about such an element as sulfur.
In the periodic table of chemical elements, sulfur is located in the 16th group, just below oxygen.
Sulfur has been known to mankind since ancient times, as it can be found in its free form,
especially near volcanoes or geothermal springs.
However, the chemical mechanisms of the formation of elemental sulfur in the earth's crust are still unclear.
Also, in nature, sulfur can be found in a very beautiful mineral "Pyrite",
that is, iron disulphide, as well as in other sulfur-containing minerals.
Many of you have seen elementary sulfur in normal life, it is usually the so-called monoclinic sulfur,
but, in the hot conditions of volcanoes, sulfur can form beautiful crystals,
the so-called crystalline sulfur.
Such crystals are very rare,
since their formation can take thousands of years.
The sulfur powder has usually a yellow color,
but if sulfur is cooled in liquid nitrogen, then its color will change to practically white.
At low temperature, sulfur atoms will reflect a larger spectrum of light.
Also, if the sulfur powder is heated to 160 degrees, it will melt,
forming a melt of sulfur that has a dark brown color.
When pouring such melt into the water, plastic sulfur is then formed,
which resembles rubber, it also stretches well and can be molded.
Plastic sulfur at the molecular level is a polymer, such as plastic in plastic bags.
However, over time, plastic sulfur goes back into the monoclinic state.
After a couple of days of storage it becomes fragile and can easily break in hands.
Such a variety of different molecular structures of the same substance is called allotropy.
Sulfur powder is added to the rubber in car tires.
It increases the strength and wear resistance of rubber as a result of creating stronger polymer bonds.
The sulfur powder is readily soluble in non-polar solvents, for example, such as the toluene.
To dissolve all the sulfur in toluene, the mixture must be heated.
Eventually, all the sulfur dissolves and the solution becomes yellow-ish.
When the solution begins to cool down, the solubility of sulfur in toluene decreases, and, over time,
beautiful needle crystals of monoclinic sulfur begin to crystallize from the solution.
This method is sometimes used to purify sulfur from impurities.
In air, sulfur burns quite well with a dull blue flame, forming sulfur dioxide.
This gas has a very unpleasant smell.
Often, sulfur is ignited in greenhouses to disinfect the soil and the hothouse itself
from the insect pests with the help of sulfur dioxide.
However, if it is to be ignited in pure oxygen,
the burning sulfur will simply shine with a beautiful blue flame, burning almost without a residue.
Also, sulfur can react with some metals, one of them being zinc.
When the powder of zinc and sulfur is ignited, a large amount of energy is released,
and the mixture itself burns with a blue-green flame due to zinc ions.
The resulting reaction product is zinc sulphide.
In the reaction of sulfur with cesium, which is the most active metal on Earth,
the reaction proceeds much faster and more effectively, forming cesium sulphide.
Also, there is one very effective reaction, which will help you get sulfur.
In a tall cylinder, carbon disulphide is mixed, which is a toxic liquid with a very unpleasant odor,
and then nitrous oxide, which can be found as propylene in pressurized bottles of whipped cream.
Later when the carbon disulfide vapors get mixed with nitrous oxide, we ignite this mixture of gases.
The reaction is accompanied by a very bright flash of blue.
This experiment looks especially effective in a slow-motion shot.
As a result of the chemical reaction, a plastic sulfur coating is formed on the walls of the cylinder,
which is very difficult to wash off.
And now let's talk about the most interesting, and sometimes entertaining [thing],
the smell of substances containing sulfur.
Sulfur is part of some amino acids, which form proteins that are found in living organisms.
Everyone has felt the smell of rotten eggs at some point in their life, it is caused by hydrogen sulphide,
which in small quantities is released from the decaying proteins inside the eggs.
Generally, all organic substances containing sulfur in their composition have a certain odor.
Without a doubt, the leaders in this matter are thiols, also called mercaptans,
organic compounds that have a thiol group in their composition.
These substances have such a strong odor that one liquid drop of such substance
can let a whole microdistrict in any city know of its presence.
Thiols, and, in particular, ethanethiol, are added to natural gas
so that a person can sense the leakage of gas and react to it in time.
For example, the smell of ethanethiol can be readily felt by a person
at a concentration of 3 particles per 100 million air particles.
Also, as an example, dimethyl sulphide has a very nasty smell,
I remember at my university we opened the jar in a corridor for 10 seconds,
after that the whole floor was already saturated with the smell of flatulence,
which caused the professors to have some questions.
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