What is zinc? Formula, zinc compounds. Application of zinc

One of the metals that were discovered long ago, but to this day have not lost their relevance in use due to their remarkable properties, is zinc. Its physical and chemical properties make it possible to apply the material in a wide variety of technical and everyday industries. He has a significant impact on human health.

A brief history of opening an item

What is zinc, people knew before our era. After all, it was then learned to use alloys containing this metal. The Egyptians used ores containing copper and zinc, alloyed them and obtained a very strong, oxidation-resistant material. Objects of everyday life, utensils made of this material were found.

The name zinc is found in the writings of the doctor Paracelsus in the 16th century AD. In the same period, the metal is actively used by the Chinese, casting coins from it. Gradually, knowledge about this substance and its good technical properties are transferred to Europe. Then in Germany, England also learned what zinc is and where it can be used.

Brass was one of the first and most famous alloys used since the ancient centuries in Cyprus, and later in Germany and other countries.

The name comes from the Latin zincum, but the etymology is not entirely clear. There are several versions.

1. From the German zinke, which translates as "tip".
2. From the Latin zincum, which means "white plaque."
3. Persian "cheng", that is, a stone.
4. Ancient German zinco, which translates as "plaque", "thorn in the eye."

Today's name was given to the element only at the beginning of the 20th century. The significance of zinc ions in the human body also became known only relatively recently (XX century). Before, no illnesses with this element were connected.

However, it is known that already in ancient times, many nations used soup from the young lamb's meat as a means of recovery from illness and for early amendment. Today we can say that the effect was achieved due to zinc ions, which contain a lot of this dish. He helped restore blood circulation, relieve fatigue and activate brain activity.

Element Zinc: Characteristic

This element is located in the periodic system in the second group, an auxiliary subgroup. The order number is 30, the mass of Zinc is 65.37. The only and constant degree of oxidation +2. Electronic configuration of the outer layer of the atom 4s ² .

In the table, Zinc, Copper, Cadmium, Chromium, Manganese and many others are transition metals. These include all those in which the electrons fill the external and pre-existing d and f energy sublevels.

The transition metals include the platinum group (Gold, Iridium, Palladium, Platinum, Osmium and others). All of them are characterized by the formation of complex compounds in which they act as a complexing agent with different coordination numbers. All this is typical for the element we are considering.

There are 5 naturally stable isotopes with mass numbers from 64 to 70. ⁶⁵ Zn is radioactive, with a half-life of 244 days.

Zinc as a simple substance

What is zinc in the usual way? It is metal, silver-blue, quickly covered with a protective oxide film in the air. Because of this, it seems that he is not very brilliant. However, it is worth removing the film, as zinc shows the properties of all metals - a beautiful characteristic shine and radiance.

In nature it is contained in many minerals and ores. So, the most common of them are:

• Zinc blende, or sphalerite;
• Kleofan;
• Marmatitis;
• Wurtzite;
• Smithsonite;
• Calamine;
• zincite;
• Willemite;
• Franklenite and others.

As part of mixed ores, Zinc usually meets with its regular companions, such as:

• Thallium;
• Germanium;
• Indium;
• Gallium;
• Cadmium.

In total, the share of this metal in the earth's crust is 0.076%. This is slightly more than copper. Also, 0.07 mg / l of this substance is contained in seawater.

The formula of zinc as a simple substance is Zn. The crystal lattice is hexagonal, dense. Type of chemical bond - metal.

Physical properties

Several characteristics can be indicated.

1. Color - silver-blue.
2. The density is 7.13 g / cm ³ .
3. The melting point is 420 ° C (it belongs to the group of low-melting metals).
4. Under normal conditions - a fragile substance.
5. The boiling point is 906 ° C.
6. When heated to 100-150 ^o C, ductility and ductility increase, it is possible to manufacture wire and roll into foil.
7. Over 200 ^o C is easily ground into a gray powder, losing its plasticity.
8. Is an excellent conductor.
9. The thermal conductivity is good, as is the heat capacity.

Such physical parameters allow the use of metal in connections with other elements. For example, zinc alloy brass is widely known.

Chemical properties

Under normal conditions, the surface of a piece of metal is immediately covered with a gray-white dull coating - zinc oxide. This is due to the fact that the oxygen of the air instantly oxidizes the pure substance.

If, for a long time, pure metal is stored in open moist air, then it will be destroyed by the action of carbon dioxide. As a simple matter, zinc reacts with:

• Halogens;
• Chalcogenes;
• Oxygen;
• Acids;
• Alkalis;
• Ammonia and ammonium (its salts);
• Weaker metals.

Does not react with nitrogen. If we take chemically absolutely pure zinc, then it does not react with any of the listed substances.

It is obvious that zinc is an amphoteric metal. In reactions with alkalis, it forms complex compounds-hydroxo-succinates.

Zinc compounds

These can be called several main categories:

1. Zinc silicide.
2. _Three- dimensional carbide - Ni ₃ ZnC.
3. Zinc halides (chloride, fluoride, iodide, bromide).
4. Sulphide, selenide, zinc arsenide.
5. Phosphide and boride.
6. Ammiakatnye complexes formed by the interaction of metal with a solution of ammonia.
7. Cyanides, thiosulphates and thiocyanates exist as the corresponding complexes in an aqueous solution.
8. Oxide and zinc hydroxide are amphoteric compounds used for the preparation of hydroxyzincate complexes.

Most compounds of the element in question are used in the chemical industry or other industries (engineering, household synthetics, paint and varnish industry).

Zinc oxide is widely used in medicine. It has a good anti-inflammatory effect, slightly dries and kills bacteria. Therefore, it is used in cosmetic products for the treatment of acne, gums, acne and other skin diseases.

Zinc salts

Practically all salts that are not double and complex, that is, do not contain extraneous colored ions, are colorless crystalline substances. The most popular in terms of human use are the following.

1. Zinc chloride is ZnCL _2. Another name for the compound is soldering acid. Outwardly it is white crystals, which absorb the moisture of the air. Used to clean the surface of metals before soldering, to obtain fiber, in batteries, to impregnate the wood before processing as a disinfectant.
2. Zinc sulphide. White powder, rapidly yellowing when heated. Has a high melting point, in contrast to pure metal. Used in the production of luminescent compounds applied on screens, panels and other objects. Is a semiconductor.
3. Zinc phosphide is a common poison used to get rid of gnawing animals (mice, rats).
4. Smithsonite, or zinc carbonate - ZnCO ₃ . Colorless crystalline compound, insoluble in water. It is used in petrochemical production, as well as in reactions of silk production. It is a catalyst in organic synthesis, used as fertilizer for soils.
5. Zinc acetate is (CH ₃ COO) ₂ Zn. Colorless crystals, readily soluble in all solvents of any nature. It finds wide application both in chemical, and in medical and food industries. Used to treat nosafaringitis. It is used as a food supplement E650 - freshens breath, prevents the appearance of plaque on the teeth when it is part of chewing gum. It is also used for etching of dyes, preservation of wood, production of plastics and other organic syntheses. Almost everywhere plays the role of an inhibitor.
6. Zinc iodide is a white crystal used in radiography, as an electrolyte in batteries, as a dye for electronic microassay.
7. Black or dark green crystals, which can not be obtained by direct synthesis, since zinc with nitrogen does not react. Formed from ammonia metal. At high temperatures decomposes with the release of zinc, so it is used to produce it.
8. Zinc nitrate. Colorless hygroscopic crystals. The use of zinc in this form is carried out in the textile and leather industries for etching tissues.

Zinc alloys

As mentioned above, there is the most common zinc alloy - brass. It is known from the very antiquity and is actively used by people till now. What does he represent?

Brass is copper and zinc, which are in harmony with several other metals, giving extra gloss, strength and refractory to the alloy. Zinc in the composition as an alloying element, copper - as the main. The color of the material is yellow, shiny, but it is black in the open air in a humid environment. The melting point is about 950 ° C, it can vary depending on the zinc content (the more it is, the lower the temperature).

The material is well rolled into sheets, pipes, welded by a contact method. It has good technical characteristics, therefore the following elements are made from it:

1. Machine parts and various technical devices.
2. Sleeves and stamped products.
3. Nuts, bolts, nipples.
4. Armatures, bushings, anti-corrosion parts of different types of transport.
5. Details of hours.

Most of the metal we are extracting in the world is spent on the production of this alloy.

Another type of intermetallic compound is zinc antimonide. Its formula is Zn ₄ Sb _3. It is also an alloy that is used as a semiconductor in transistors, thermal imagers, magnetoresistive devices.

It is obvious that the use of zinc and its compounds is very wide and almost universal. This metal is as popular as copper and aluminum, silver and gold, manganese and iron. Its importance for technical purposes as an anticorrosive material is especially great. After all, zinc is covered with different alloys and products to protect against this destructive natural process.

Biological role

What is zinc in terms of medicine and biology? Does it matter to the life of organisms and how big is it? It turns out that zinc ions simply must be present in living things. Otherwise, the deficit will lead to the following consequences:

• Anemia;
• Insulin reduction;
• Allergies;
• Loss of weight and memory;
• Fatigue;
• Depression;
• Impaired vision;
• Irritability and others.

The main places for the concentration of zinc ions in the human body are the pancreas, liver and muscles. It is also this metal that forms part of most enzymes (eg, carbonic anhydrase). Therefore, most catalysis reactions occur with the participation of zinc.

What exactly do the ions do?

1. They participate in the synthesis of male hormones and seminal fluid.
2. Contribute to the assimilation of vitamin E.
3. Participate in the splitting of alcohol molecules in the body.
4. They are direct participants in the synthesis of many hormones (insulin, growth hormone, testosterone and others).
5. Takes part in the hematopoiesis and healing of damaged tissues.
6. Regulates the secretion of sebaceous glands, supports the normal growth of hair and nails, promotes regenerative processes in the skin.
7. Has the ability to eliminate toxins from the body and strengthen immunity.
8. It influences the formation of taste sensations, as well as the sense of smell.
9. Participates in the processes of transcription, the exchange of vitamin A, nucleic synthesis and decays.
10. Is a participant in all stages of growth and development of the cell, and also accompanies the process of gene expression.

All this proves once again how important the element is in this metal. His role in biological systems was clarified only in the twentieth century. Many troubles and ailments in the past could be avoided if people knew about the treatment with the help of preparations based on zinc.

How can you maintain the right amount of this element in the body? The answer is obvious. It is necessary to use products containing zinc. The list can be long, so let's specify only those in which the maximum number of the element in question is:

• Nuts and seeds;
• Beans;
• meat;
• Seafood, especially oysters;
• Cereals and bread;
• milk products;
• Greens, vegetables and fruits.

Using Man

We have already generally indicated in which industries and industries zinc is used. The price of this metal and its alloys is quite high. For example, a sheet of brass measuring 0.6 x 1.5 is estimated at about 260 rubles. And this is justified, because the quality of the material is quite high.

So, metallic zinc, that is, as a simple substance, is used:

• For coating against corrosion on iron and steel products;
• In batteries;
• Printing;
• As a reducing agent and catalyst in organic synthesis;
• In metallurgy for the separation of other metals from their solutions.

Zinc oxide is used not only for cosmetic purposes, which we have already mentioned, but also as a filler in the production of rubber, as a white pigment in paints.

About where different zinc salts are used, we talked about these compounds. Evidently, in general, zinc and its substances are important components that are important in industry, medicine and other branches, without which many processes would be impossible or very difficult.