Mercuric Sulphide: Formula

The chemical substance mercuric sulphide, otherwise called cinnabar, is a very toxic compound. This is the most common mercury mineral. It has been used since antiquity as a dye. But during treatment, this mineral can release toxic compounds and cause poisoning. Therefore, now cinnabar is used only for the extraction of mercury, which is used in industry and medicine.

Mercuric Sulphide Mineral

It is called a cinnabar. This word came from the ancient Persian combination of "blood dragon." This is exactly the way in the countries of the Ancient East mercury sulphide was also called for its red color. On the cleavage this stone is so bright that it resembles a drop of blood. In air, it rapidly oxidizes, acquiring a bluish-gray color. Very rarely there is this mineral in the form of individual crystals. Usually it is solid mass or plaque. Cinnabar also occurs in the form of veins, crusts and inclusions in limestone and clayey rocks.

Another modification of mercury sulphide is the mineral metacinnabarite. This powder is black, very rare in nature. Even more rare minerals with the content of mercury sulfide are actasite, guadalkarcite, opofrite, saukovit and others.

Distribution in nature

Mercury sulphide is the most common mercury mineral on Earth. It is formed in hydrothermal deposits close to the surface. This mineral is mined together with quartz, pyrite, calcite and other rocks. The largest field of mercury sulphide, developed for two millennia, is in Spain. It is called Almaden, it produces about 80% of the world's mercury reserves. Large deposits are also in Slovenia, Yugoslavia, the United States. Separate ancient mines, developed now, are in Rome, the Donbas, Central Asia, Primorye.

Properties

This mineral contains more than 80% of mercury. It is he who is the main source of this metal. Since mercury has long been known and used in industry, so mercury sulphide is so often used. The formula of this substance is HgS, in another way it is also called sulfur mercury. A special feature of the mineral is its physical and chemical properties:

• Bright red color;
• On the cleave - it shines;
• Thin plates of mineral are almost transparent, resemble a diamond;
• Very fragile;
• Has a high density, so very heavy;
• Easily melts;
• If heated to 200 degrees, evaporates with the release of mercury vapor;
• Is dissolved in a mixture of nitric and hydrochloric acids.

Usage history

It is believed that the cinnabar was known to mankind 15 thousand years ago. It was discovered in the rock art. Even in ancient Rome, in Egypt and Byzantium, mercury sulfide was mined to produce this metal and a natural red pigment. Pieces of cinnabar were used even for making souvenirs.

The oldest deposits, preserved to the present day, are in Rome, Gorlovka, the Fergana Valley in the territory of Uzbekistan, in Tajikistan. They were developed under inhuman conditions, the workers often died from poisoning.

Cinnabar was very appreciated in ancient times because of its bright scarlet color. And they extracted it for 500 years before our era. In addition, it was used to produce mercury. This metal was very much appreciated and used as a medicine of immortality. Because of their special properties, mercury was called liquid silver and was often used in alchemy. This metal was given the leading place in all experiments.

Receiving

Even in ancient China was first obtained artificial cinnabar. By fusing mercury with sulfur, alchemists obtained red mercury sulphide back in the 9th century. And the artists of the Middle Ages used artificial cinnabar in their paintings. Now two methods of obtaining mercury sulphide are used: dry and wet. In dry production, mercury is mixed with sulfur and heated. This produces a black substance. It is then sublimated and condensed. A wet method was tested in the 18th century. At the same time mercury and sulfur were rubbed with water and mixed with caustic soda. After complex manipulations, a red mercury sulphide was obtained. But it is less stable and turns black in the light.

The process of obtaining artificial cinnabar is very dangerous for humans, as it is accompanied by the release of toxic mercury compounds. Therefore, it is only possible in a laboratory with safety rules. In addition, the disadvantage of artificial cinnabar is that it can eventually acquire a bluish or almost black tinge. This happens already in a layer of paint.

Danger of this substance

Mercury is a very toxic metal. And cinnabar, too, can cause severe poisoning, since it can emit fumes of mercury even under normal conditions. And this is the strongest neurotoxic drug. It affects the brain, the nervous system, negatively affects the kidneys and liver. Mercury vapor is odorless and inhalation affects the respiratory tract. Therefore, the risk of mercury refers to the first class - the most dangerous chemicals. When a person is poisoned, convulsions, loss of sensitivity, paralysis of vital centers, suppression of cardiac activity, hallucinations and death occur.

Mercury sulphide: application

Cinnabar is the best source of mercury. But besides this, from the antiquity this mineral was used as a bright natural dye. Cinnabar was used as a paint for painting icons, drawing capital letters in the Bible, making souvenirs. In icon painting as a paint, it is often used now. But in secular painting from the 19th century it was replaced by safer cadmium paints. In addition, prior to the invention of antibiotics, mercuric sulfide was used as an effective medicine for syphilis, an antiseptic and a laxative.

Now mercury, extracted from cinnabar, is widely used in industry:

• When manufacturing thermometers;
• In electrical engineering;
• For filling fluorescent lamps;
• For the production of barometers;
• When manufacturing mirrors;
• For the soldering of many metals and gold mining;
• In pharmaceuticals, for example, for the preservation of vaccines;
• In the middle of the 20th century it was part of dental fillings;
• Alloys of mercury with other metals are widely used in jewelry;
• As a fungicide in agriculture.