one of the metals that have been opened a long time ago, but to this day has not lost its relevance to use thanks to its remarkable properties is zinc.Its physical and chemical properties allow to use the material in various branches of engineering and life.It has a significant impact on human health.
A Brief History of the opening element
What is zinc, people knew before our era.It was then learned to use alloys containing this metal.The Egyptians used ores containing copper and zinc, fused them and received very durable, resistant to the oxidation of the material.They were found household items, dishes made from this material.
name zinc is found in the writings of physician Paracelsus in the XVI century BC.At the same time the metal is actively start using Chinese molding of a coin.Gradually, the knowledge of this matter and its good technical properties of moving to Europe.Then in Germany, England also learned that a zinc and where it can be used.
Brass was one of the first and most well-known alloys used since ancient times in Cyprus, and later in Germany and other countries.
name comes from the Latin zincum, but the etymology is not entirely clear.There are several versions.
- From German zinke, which translates as "island".
- From Latin zincum, which means "white patches."
- Persian "Cheng", ie rock.
- drevnegermanskogo zinco, which translates as "plaque", "an eyesore."
Today the name of the item is received only at the beginning of the XX century.The significance of zinc ions in the human body as it became known only recently (XX century).Before that no illnesses with this element is not connected.
However, we know that in ancient times, many people used Soup of lamb meat as a means of recovery from illness and for the speedy amendment.Today we can say that the effect is due to zinc ions, which in this dish contains a lot.He helped restore blood circulation, relieve fatigue and activated brain activity.
Element Zinc characteristic
This item is located in the periodic table in the second group, the sub-groups.The sequence number 30, the mass of Zinc - 65.37.The only constant and the degree of oxidation of +2.The electronic configuration of the outer layer of the atom 4s2.
table zinc, copper, cadmium, chromium, manganese and many others - is the transition metals.These include all those who filled the outer electrons and predvneshny d and f energy sublevels.
Transition metals include platinum group and (gold, iridium, palladium, platinum, osmium, and others).For all of them characterized by the formation of complex compounds in which they act as a complexant with different coordination numbers.All this is also characteristic of the element under consideration.There
5 stable isotopes in nature with mass numbers from 64 to 70. 65Zn - radioactive, with a half-life of 244 days.
Zinc as a simple substance
What is zinc in the usual form?It - metal, silver blue, quickly covered with a protective oxide film on the air.Because of this, it seems that he is not very brilliant.However, the film is removed, as zinc exhibits properties of metals - a beautiful characteristic luster and shine.
In nature, found in the composition of many minerals and ores.Thus, the most common ones are:
- zinc blende or sphalerite;
- kleyofan;
- marmatit;
- wurtzite;
- smithsonite;
- calamine;
- zinc
- willemite;
- franklenit and others.
in mixed ores Zinc is usually found together with their constant companions, such as:
- Thallium;
- Germanium;
- India;
- Gallium;
- Cadmium.
total in the earth's crust at a fraction of the metal accounts for 0.076%.It is slightly larger than copper.Also, 0.07 mg / l of the substance contained in seawater.
Formula zinc as a simple substance - Zn.Crystalline hexagonal, thick.Type of chemical bond - metal.
physical properties
can indicate several characteristics.
- Color - srebristo blue.
- density - 7.13 g / cm3.
- Melting point - 420 ° C (refers to a group of low-melting metals).
- Under normal conditions - a delicate matter.
- Boiling point - 906 ° C.
- When heated to 100-150 ° C increases the ductility and formability, manufacturing wire and rolled in foil.
- over 200 ° C is easily pounded into a gray powder, losing flexibility.
- is an excellent conductor.
- good thermal conductivity, as well as the specific heat.
Such physical properties allow the use of metal compounds with other elements.For example, well-known zinc alloy - brass.
chemical properties
Under normal conditions, the surface is covered with a piece of metal instantly dull gray-white patina - zinc oxide.This stems from the fact that the oxygen in the air oxidizes immediately pure substance.
If a long time to keep a pure metal in the open air wet, there will be its destruction under the influence of carbon dioxide.As simple substance reacts with the zinc:
- halogens;
- chalcogens;
- oxygen;
- acids;
- alkalis;
- ammonia and ammonium (its salts);
- weaker metals.
does not react with nitrogen.If we take a chemically completely pure zinc, it does not react with anything of the listed substances.
Obviously, zinc - amphoteric metal.If reactions with alkalis forming complex compounds - gidroksotsinkaty.
Zinc compounds are such we can name a few major categories:
- silicide zinc.
- triple carbide type - Ni3ZnC.
- zinc halide (chloride, fluoride, iodide, bromide).
- sulfide, selenide, zinc arsenide.
- phosphide and boride.
- ammine complexes formed by reacting metal with ammonia.
- cyanides, thiocyanates and thiosulfates exist as the corresponding complexes in aqueous solution.
- oxide and zinc hydroxide - amphoteric compounds used to prepare the complexes gidroksotsinkatov.
Most of the compounds of the element used in the chemical industry or other industries (technology, consumer syntheses, paint industries).
Zinc oxide is widely used in medicine.It has good anti-inflammatory action, slightly dries and kills bacteria.Therefore, it is used in cosmetics for the treatment of acne, comedones, acne and other skin conditions.Zinc salts
Almost all the salts that are not double and complex, i.e. do not contain foreign ions stained - is a colorless crystalline substance.The most popular in terms of human use are the following ones.
- Zinc chloride - ZnCL2.Another name for the connection - soldering acid.Outwardly a white crystals, air absorbs moisture.It is used for cleaning metal surfaces before soldering, producing fibers, in batteries, for impregnation of wood before treatment as a disinfectant.
- zinc sulfide.White powder, yellowing when heated rapidly.It has a high melting point, as opposed to pure metal.Used in the manufacture of luminescent compounds applied to the screens, panels and other items.It is a semiconductor.
- Zinc phosphide - a common poison used to get rid of gnawing animals (mice, rats).
- Smithson, or zinc carbonate - ZnCO3.Colorless crystalline compound, insoluble in water.It used in petrochemical production, as well as in reactions producing silk.Is a catalyst in organic synthesis, used as a fertilizer for the soil.
- Zinc Acetate - (CH3COO) 2Zn.Colourless crystals, very soluble in all the solvents of any kind.It is widely used in the chemical and in the medical and food industries.Used to treat nozafaringita.It is used as a food additive E650 - freshens breath, prevents the appearance of plaque on the teeth, as a part of the gum.It is used for etching dyes, wood preservatives, plastics and other organic syntheses.Almost everywhere plays the role of an inhibitor.
- Iodide Zinc - white crystals used in radiography, as electrolyte in batteries, as a dye for electronic microstudies.
- black or dark-green crystals, which can not be obtained by direct synthesis, since zinc does not react with nitrogen.Formed from metal ammine.At high temperatures it decomposes to release zinc, therefore applicable to its preparation.
- zinc nitrate.Colorless hygroscopic crystals.The use of zinc in this form is carried out in the textile and leather industry for etching fabrics.
Zinc alloys
As mentioned above, there are the most common zinc alloy - brass.That it is known to the most ancient and widely used by people so far.What is it?
Brass - a copper and zinc, which are in harmony with several other metals, giving extra shine, durability and high-melting alloys.Zinc in the composition as the alloying element, copper - as a basic.Material color yellow, brilliant, but in the open air in a moist environment is able to duck.The melting point of about 950 ° C, may vary depending on the content of zinc (the larger it is, the temperature is lower).
Material well-rolled into sheets, tubes, welded by contact.It has good technical specifications, so it made of the following elements :.
- machine parts and various technical devices.
- liners and moldings.
- Nuts, bolts and fittings.
- fittings, bushings, anti-corrosive parts of different types of transport.Details
- hours.
Most of the world's metal goes before us is for the manufacture of the alloy.
Another type intermetallic compound - zinc antimonide.Formula his Zn4Sb3.It is also an alloy, which is used as a semiconductor in transistors, thermal imagers, magnetoresistive devices.
It is obvious that the use of zinc and its compounds are widely and almost everywhere.This metal is also popular as copper, aluminum, silver, gold, manganese and iron.Especially great its value for technical purposes as a corrosion-resistant material.After all, they are covered by different zinc alloys and products to protect against the destructive nature of this process.
biological role
What is zinc in terms of medicine and biology?Does it have significance for the life of organisms and how great it is?It turns out that just the zinc ions must be present in living beings.Otherwise, the deficit would lead to the following consequences:
- anemia;
- reduce insulin;
- allergies;
- weight loss and memory;
- fatigue;
- depression;
- eyesight;
- irritability and others.
main areas of concentration of zinc ions in the human body - is the pancreas, liver and muscles.Also this metal is included in most enzyme (e.g., carbonic anhydrase).Therefore, most of the reactions of catalysis occurs with the participation of zinc.
what makes the ions?
- involved in the synthesis of male hormones and sperm.
- promotes the absorption of vitamin E.
- participate in the cleavage of the alcohol molecules in the body.
- a direct participant of the synthesis of many hormones (insulin, growth hormone, testosterone and others).
- takes part in blood formation and healing of damaged tissue.
- regulates the secretion of the sebaceous glands, supports the normal growth of hair and nails, promotes regenerative processes in the skin.
- has the ability to eliminate toxins from the body and strengthen the immune system.
- influence the formation of taste, and smell.
- takes part in the process of transcription, metabolism of vitamin A, nucleic synthesis and breakdown.
- is party to all stages of growth and development of cells, and also accompanies the process of gene expression.
All this proves once again how important this element is metal.Its role in biological systems was clarified only in the XX century.Many troubles and ailments in the past could have been avoided if people knew about the treatment by means of preparations based on zinc.
How can we maintain the right amount of this element in the body?The answer is obvious.You must eat foods containing zinc.The list can be long, so we mention only those in which the maximum number of the element:
- nuts and seeds;
- legumes;
- meat;
- seafood, especially oysters;
- cereals and breads;
- dairy products;
- greens, vegetables and fruits.
Human uses
We have a whole indicates which sectors and industries using zinc.The price of this metal and its alloys are quite high.For example, brass sheet size 0.6 x 1.5 estimated at about 260 rubles.And rightly so, because the quality of the material is sufficiently high.
Thus, zinc metal, that is, as a simple substance is used:
- coating against corrosion of iron and steel products;
- in batteries;
- printing;
- as a reducing agent and a catalyst in organic synthesis;
- in metallurgy for separation of other metals from solutions thereof.
Zinc oxide is not only used for cosmetic purposes, which we have already mentioned, but also as a filler in the manufacture of rubber, as a white pigment in paints.
About where different zinc salts, we talked in the consideration of these compounds.It is obvious that in general, zinc and substance - is important and significant in industry, medicine and other branches of the components, without which many of the processes would be impossible or severely hindered.
