What is zinc? Formula, zinc compounds. Zinc application

One of the metals that have been discovered for a long time, 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 use the material in a wide variety of industries and households. It has a significant impact on human health.

A brief history of the discovery of the element

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

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

Brass was one of the first and most famous alloys used since ancient times 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 German zinke, which translates to "spearhead".
2. From Latin zincum, which means "white plaque."
3. Persian "cheng", that is, a stone.
4. Ancient German zinco, which translates as "plaque", "eyesore."

The element got its current name only at the beginning of the 20th century. The value of zinc ions in the human body also became known only relatively recently (XX century). Prior to this, no ailments have been associated with this element.

However, it is known that already in ancient times, many peoples used soups from the meat of a young lamb as a means of recovery from illness and for a speedy correction. Today we can say that the effect was achieved due to zinc ions, which are quite a lot in this dish. He helped restore blood circulation, relieve fatigue and activated brain activity.

Zinc Element: Feature

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

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

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 complexing agents with different coordination numbers. All this is also characteristic of the element we are considering.

There are 5 stable in nature 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 its usual form? It is a metal, silver-blue, quickly coated with a protective oxide film in air. Because of this, it seems that it is not very brilliant. However, it is worth removing the film, as zinc exhibits 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;
• gleophan;
• marmatite;
• wurtzite;
• smitsonite;
• calamine;
• zincite;
• willemite;
• frankenitis and others.

As part of mixed ores, Zinc is usually found together with its constant 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 a little more than copper. Also 0.07 mg / l of this substance is found in sea water.

The formula of zinc as a simple substance is Zn. The crystal lattice is hexagonal, dense. The type of chemical bond is metallic.

Physical properties

Several characteristics can be identified.

1. Color - silver-blue.
2. Density - 7.13 g / cm ³ .
3. The melting point is 420 ° C (refers to the group of low-melting metals).
4. Under normal conditions, a brittle substance.
5. Boiling point - 906 ^about C.
6. When heated to 100-150 ° C, the ductility and ductility increases, it is possible to manufacture wire and roll into foil.
7. Above 200 ° C, it is easily rubbed into a gray powder, losing plasticity.
8. It is an excellent conductor.
9. Thermal conductivity is good, as is heat capacity.

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

Chemical properties

Under ordinary conditions, the surface of a piece of metal is instantly covered with a gray-white dull coating - zinc oxide. This is due to the fact that atmospheric oxygen instantly oxidizes a 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 substance, zinc reacts with:

• halogens;
• chalcogenes;
• oxygen;
• acids;
• alkalis;
• ammonia and ammonium (its salts);
• weaker metals.

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

Obviously, zinc is an amphoteric metal. When reacting with alkalis, it forms complex compounds - hydroxyzincates.

Zinc compounds

These can be called several main categories:

1. Zinc silicide.
2. Triple type carbide - Ni ₃ ZnC.
3. Zinc halides (chloride, fluoride, iodide, bromide).
4. Sulfide, selenide, zinc arsenide.
5. Phosphide and Boride.
6. Ammonia complexes formed during the interaction of a metal with a solution of ammonia.
7. Cyanides, thiosulfates and thiocyanates exist as corresponding complexes in aqueous solution.
8. Zinc oxide and hydroxide are amphoteric compounds used to obtain complexes of hydroxyl zincates.

Most of the compounds of this element are used in the chemical industry or other industries (engineering, household syntheses, 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 cosmetics for the treatment of acne, comedones, acne and other skin diseases.

Zinc salts

Almost 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. Externally, it is a white crystal that absorbs moisture well. It is used to clean the surface of metals before soldering, to obtain fiber, in batteries, to impregnate wood before processing as a disinfector.
2. Zinc sulfide. White powder, quickly yellowing when heated. It has a high melting point, unlike pure metal. It is used in the production of luminescent compositions applied to screens, panels and other items. It 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 . A colorless crystalline compound, insoluble in water. It is used in petrochemical production, as well as in silk production reactions. It is a catalyst in organic synthesis, used as fertilizer for soils.
5. Zinc Acetate - (CH ₃ COO) ₂ Zn. Colorless crystals, soluble in all solvents of any nature. It is widely used in both the chemical and medical and food industries. Used to treat nosafaringitis. It is used as a food supplement E650 - freshens the breath, prevents the appearance of plaque on the teeth when it is part of the chewing gum. It is also used for pickling dyes, preserving wood, manufacturing plastics and other organic syntheses. Almost everywhere it plays the role of an inhibitor.
6. Zinc iodide - white crystals used in radiography, as an electrolyte in batteries, as a dye for electronic micro studies.
7. Black or dark green crystals that cannot be obtained by direct synthesis, since zinc does not react with nitrogen. Formed from metal ammonia. At high temperatures, it decomposes with the release of zinc, so it is used to obtain it.
8. Zinc nitrate. Colorless hygroscopic crystals. The use of zinc in this form is carried out in the textile and leather industries for dressing fabrics.

Zinc Alloys

As mentioned above, the most common zinc alloy is brass. It is he who has been known since antiquity and is actively used by people until now. What is he like?

Brass is copper and zinc, which are harmoniously combined with several other metals that give additional shine, strength and refractoriness to the alloy. Zinc in the composition as an alloying element, copper - as the main. The color of the material is yellow, shiny, but in the open air in a humid environment it can blacken. The melting point is about 950 ° C, may vary depending on the zinc content (the more it is, the lower the temperature).

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

1. Machine parts and various technical devices.
2. Sleeves and stamped products.
3. Nuts, bolts, nozzles.
4. Armatures, bushings, anti-corrosion parts of different types of vehicles.
5. Watch details.

Most of the metal mined in the world under consideration by us goes precisely to the manufacture 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.

Obviously, the use of zinc and its compounds is very widespread and almost universal. This metal is as popular as copper and aluminum, silver and gold, manganese and iron. Especially great is its importance for technical purposes as an anti-corrosion material. After all, it is zinc that covers various alloys and products to protect against this destructive natural process.

Biological role

What is zinc from the point of view of medicine and biology? Does it matter for the life of organisms and how great 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
• weight loss and memory;
• fatigue
• Depression
• visual impairment;
• irritability and others.

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

What exactly do ions do?

1. Participate in the synthesis of male hormones and seminal fluid.
2. Promote the absorption of vitamin E.
3. Participate in the breakdown of alcohol molecules in the body.
4. They are direct participants in the synthesis of many hormones (insulin, growth hormone, testosterone and others).
5. It takes part in blood formation and healing of damaged tissues.
6. Regulates the secretion of the sebaceous glands, supports the normal growth of hair and nails, promotes regenerative processes in the skin.
7. It has the ability to eliminate toxins from the body and strengthen the immune system.
8. Affects the formation of taste sensations, as well as smell.
9. It takes part in transcription processes, vitamin A metabolism, nucleic synthesis and decay.
10. It is a participant in all stages of cell growth and development, and also accompanies the process of gene expression.

All this once again proves how important this metal is. Its role in biological systems was clarified only in the 20th century. Many troubles and ailments in the past could have been avoided if people had known about the treatment with zinc-based drugs.

How can we maintain the right amount of this element in the body? The answer is obvious. It is necessary to eat foods containing zinc. The list can be long, therefore we will indicate only those in which the maximum number of the item in question is:

• nuts and seeds;
• legumes;
• meat;
• seafood, especially oysters;
• cereals and bread;
• milk products;
• greens, vegetables and fruits.

Human use

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 brass sheet measuring 0.6 x 1.5 is approximately estimated at 260 rubles. And this is quite 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 houses;
• as a reducing agent and catalyst in organic syntheses;
• 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.

We talked about where various zinc salts are used when considering these compounds. Obviously, in general, zinc and its substances are important and significant components in industry, medicine and other industries, without which many processes would be impossible or very difficult.