DEFINITION

Silver located in the fifth period, group I, secondary (B) subgroup of the Periodic Table.

Refers to elements d-families. Metal. Designation - Ag. Serial number - 47. Relative atomic mass - 107.868 amu.

Electronic structure of the silver atom

The silver atom consists of a positively charged nucleus (+47), inside of which there are 47 protons and 61 neutrons, and 42\7 electrons move around in five orbits.

Fig.1. Schematic structure of the silver atom.

The distribution of electrons among orbitals is as follows:

47Ag) 2) 8) 18) 17) 2 ;

1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 2 4p 6 4d 9 5s 2 .

The valence electrons of a silver atom are those electrons located at 4 d- and 5 s-orbitals. The energy diagram of the ground state takes the following form:

The valence electrons of a silver atom can be characterized by a set of four quantum numbers: n(main quantum), l(orbital), m l(magnetic) and s(spin):

Examples of problem solving

EXAMPLE 1

EXAMPLE 2

Silver is a chemical element with atomic number 47 in the periodic table D.I. Mendeleev. Chemical formula silver Ag.

Lomonosov wrote about silver that this metal, if free from impurities, appears white, like chalk. And indeed it is.

Silver was known back in the 4th millennium BC. This precious metal, like gold, occurs in nature in the form of nuggets. Therefore, humanity became acquainted with it without the help of scientists. In ancient Egypt, silver was called “white gold.” It was more difficult to mine than gold. Therefore, in those days it was worth more than gold.

It is believed that silver received its Latin name argentum from the Greek argos - white, sparkling, shining.

In nature, silver is found both in the form of nuggets and in the form of rare minerals, which are included in polymetallic ores - sulfides of copper, lead, zinc. Silver nuggets have a fairly large weight. It is known that the largest nugget weighed 13.5 tons. Silver nuggets often contain impurities of gold and mercury, less often - platinum, copper, bismuth, and antimony.

Chemical properties

Silver is a metal and has all the properties of metals. But the chemical activity of silver is low. In the voltage series of metals, also called the electrochemical activity series of metals, silver is almost at the end.

At ordinary temperatures, silver does not interact with oxygen, nitrogen, hydrogen, silicon and carbon.

It reacts with sulfur under normal conditions. As a result, silver sulfide is formed.

2Ag + S = Ag 2S

Reacts with halogens when heated.

2Ag + Br 2 = 2AgBr

Everyone knows that silver items gradually darken. Why is this happening? It turns out that the reason is that silver reacts with hydrogen sulfide in the air. As a result, a film of silver sulfide Ag2S is formed on the surface of silver.

4Ag + 2H 2 S + O2 = 2Ag 2 S + 2H 2 O

How does silver react with acids? Interestingly, with nitric acid the reaction occurs differently depending on the concentration of the acid. Thus, with concentrated nitric acid, silver produces silver nitrate AgNO3 and nitrogen dioxide NO2

Ag +2HNO 3 = AgNO 3 + NO 2 + H 2 O

And as a result of the reaction with dilute nitric acid, silver nitrate AgNO3 and nitric oxide NO are formed

3Ag +4HNO3 = 3AgNO3 + NO + 2H2O

Silver reacts only with concentrated sulfuric acid

2Ag + 2H 2 SO4 = Ag 2 SO 4 + SO 2 + 2H 2 O

The reaction with hydrochloric acid occurs at high temperatures

2Ag + 2HCl = 2AgCl + H2

Physical properties and uses of silver

Silver is an amazingly ductile metal. It can be used to make a sheet with a thickness of only 0.00025 mm. And from a grain weighing 1 g, the thinnest wire 2 km long is obtained.

Silver conducts excellently electricity and warmth. In addition, it can withstand enormous loads. It is used to make various contacts in devices used on space rockets, nuclear installations, submarines, computer technology, etc.

The excellent reflectivity of silver allows it to be used in the production of mirrors, telescopes, microscopes, and various optical instruments.

Silver is widely used in jewelry. Rings, brooches, and table sets still decorate human life.

Coins are minted from silver.

Speaking about silver, one cannot fail to mention its ability to purify water from various microorganisms.

In 327 BC. The Greek army led by Alexander the Great invaded India. It seemed that nothing could stop the commander; there were no obstacles ahead. But suddenly an epidemic of gastrointestinal diseases began. The soldiers rebelled. The Greeks were forced to return home. But the sick were mainly among ordinary soldiers. Only two thousand years later did scientists understand why the military leaders almost never got sick. Soldiers drank from ordinary tin mugs, and military leaders drank from silver vessels. That is, silver killed pathogenic bacteria. Later it was found that just a few billionths of a gram of silver can destroy bacteria in 1 liter of water.

Silver compounds are widely used in the manufacture of drugs with bactericidal properties.

IN chemical industry silver is used as a catalyst in the production of organic compounds.

Silver Since ancient times it has been considered the most mysterious metal. It was often endowed with magical properties, and preference was given to it by extraordinary people: actors, artists, writers. In addition to the status of the most mysterious, silver also received the status of the purest. Being the 47th element of the periodic table, Argentum (Ag) in terms of popularity it follows immediately after gold. Silver is practically resistant to oxidation, so it retains its original shine and luster for a very long time. Isn’t this a reason to love “lunar” metal with all my heart! And also make beautiful jewelry out of it.

Jewelers highly valued and still value silver. They are grateful him for his wonderful properties: plasticity, malleability, versatility of use. A great opportunity to experiment and get outstanding results! It is no secret that it is the silver design that is extremely advantageous and Jewelry decorated with national flavor looks rich. Especially if we take into account traditional Russian crafts:

VILIGRANE, FINISH, BLACKING. Yes Thus, silver has its own, expressive and extremely eloquent language. It can be confidently called the language of international communication, since the tenderness of traditional silver jewelry, the monumentality of heavy ethnic products, the extravagance of solutions from modern designers are understandable to absolutely everyone.

Typically, special sterling silver is used to make silver jewelry. It is distinguished by the highest 925 purity, dazzling white color, and outstanding strength and durability.

Sterling silver

WITH It owes its name to the famous Easterling family, which in ancient times lived in Northern Germany. The family became famous for its impeccable honesty, for which King Edward the First gave him the honorary authority to produce royal silver coins. These coins quickly and for a long time became famous for the impeccability of their quality, which led to the formation of the common noun “sterling”, meaning the highest degree of reliability.

Moonlight

As mentioned earlier, silver is the whitest of all precious metals. Jewelers play very well on this advantage, combining brilliant white and blackened silver into elegant compositions that are difficult to remain indifferent to. The engraving technique harmoniously complements the tandem, emphasizing its uniqueness and embodying bold ideas. It is also impossible not to note the amazing ability of silver to highlight the best features appearance precious, semi-precious and ornamental stones. The varied palette of their colors is beautifully framed by moonlight or expressive blackening.

It is also known from the history of silver that it has beneficial, antibacterial properties.

Egyptian warriors used silver to treat battle wounds: they placed thin silver plates on them, the wounds were disinfected and healed quickly. In the Russian Orthodox Church, holy water for parishioners was always kept in silver vessels. There are many stories about how silver vessels saved lives by storing water in them. There is also an opinion that silver gives strength to those who wear it.

Interesting events from the history of silver

The army of the great Alexander the Great moved in battles across the countries of Asia (IV century BC). After the troops entered Indian territory, severe gastrointestinal diseases began among the soldiers...
After a series of bloody battles and magnificently celebrated victories, in the spring of 326, Alexander the Great reached the banks of the Indus. However, Alexander’s “invincible” army could not defeat its main enemy - disease. The warriors, exhausted and exhausted, refused to go forward to the banks of the Ganges, where Alexander’s thirst for conquest drew him. In the fall of 326, Alexander's troops began to retreat. The surviving descriptions of the history of the campaigns of Alexander the Great show that ordinary soldiers were sick more often than military leaders, although the latter were on the campaign in the same conditions as ordinary soldiers and equally shared with them all the inconveniences and deprivations of camp life. Only 2250 years later the reason for the various morbidity rates among the soldiers of Alexander the Great was found. It consisted in the difference in equipment: an ordinary warrior was entitled to a tin glass, and a military leader was entitled to SILVER

Meaning of the word

Silver is one of those metals that attracted the attention of man back in ancient times. Silver gets its name from the Sanskrit word “argenta”, which means “light”. The Latin "argentum" comes from the word argenta. The Latin name for silver is " argentum"like the ancient Greek "argitos", the Sumerian "ku-babbar" and the ancient Egyptian "had", means "WHITE". History of silver associated with alchemy, since already in those days the method of cupellation of silver was developed.

In Russian “silver”, in German “silber”, in English “silver” - these words go back to the ancient Indian word “sarpa”, which meant the Moon and Sickle (by analogy with the Moon) - the oldest tool of the farmer. The light shine of silver is somewhat reminiscent of the light of the Moon - silver in the alchemical period of the development of chemistry was often associated with the Moon and designated with the sign of the Moon.

The origin of some concepts and names is associated with silver. So, for example, in ancient Rus' bars of silver were a measure of the value of various items. In cases where a particular item of trade was worth less than the entire bar, a part corresponding to the value of the thing was cut off from the bar. These severed parts were called “rubles”, from which came the name of the monetary unit adopted in Russia (and at the beginning of the 20th century in Belarus) - the ruble. So the ruble was originally O was really silver

Discovery of silver. Production

The Phoenicians discovered deposits of silver (silver ores) in Spain, Armenia, Sardinia and Cyprus. Silver from silver ores was combined with arsenic, sulfur, chlorine, and also in the form of native silver. Native metal, of course, became known before they learned to extract it from compounds. Native silver is sometimes found in very large masses: the largest silver nugget is considered to be one that weighed 13.5 tons.

Silver is also found in meteorites and is found in sea ​​water. Silver is rarely found in the form of nuggets. This fact, as well as its less noticeable color (silver nuggets are usually coated with a black sulfide coating) led to the later discovery of native silver by man. This explained the great rarity and great value of silver at first. But then the second discovery of silver happened...

By refining gold with molten lead, in some cases, instead of being brighter than natural gold, a duller metal was obtained. But there was more of it than the original metal that they wanted to clean. This pale gold came into use from the third millennium BC. The Greeks called it electron, the Romans called it electrum, and the Egyptians called it asem. Currently, the term electrum can be used to refer to an alloy of silver and gold.

These alloys of gold and silver have long been considered a special metal. In ancient Egypt, where silver was brought from Syria, it was used to make jewelry and mint coins. This metal came to Europe later (approximately 1000 BC) and was used for the same purposes. It was assumed that silver was a product of the transformation of metals on the way to their “transmutation” into gold.

2500 BC in Ancient Egypt they wore jewelry and minted coins from silver, believing that it was more valuable than gold. In the 10th century it was shown that there was an analogy between silver and copper, and copper was seen as silver colored red. In 1250, Vincent Beauvais suggested that silver was formed from mercury under the action of sulfur.

In the Middle Ages, “kobald” was the name for ores that were used to produce metal with properties different from the already known silver. It was later shown that these minerals were used to produce a silver-cobalt alloy, and the difference in properties was determined by the presence of cobalt. In the 16th century Paracelsus obtained silver chloride from the elements, and Boyle determined its composition. Scheele studied the effect of light on silver chloride, and the discovery of the photograph attracted attention to other silver halides. In 1663, Glaser proposed silver nitrate as a cauterizing agent. Since the end of the 19th century. complex silver cyanides are used in electroforming.

Names from the word silver

In addition to the silver ruble, many names probably came from the word silver. Here is the origin story of the name of one of the well-known countries...
The name of one of the countries in South America - Argentina - comes from silver. The legend, in which historical facts are closely intertwined with poetic fiction, tells that in 1515 the Spanish government pilot de Solis discovered the mouth of a large river in South America, named after Solis after him. In 1527, Sebastian Cabot, traveling up the river de Solis, was amazed at the amount of silver his sailors plundered from the population. This gave Cabot a reason to call the mouth of the river La Plata - silver (in Spanish "plata" - silver, de plate - silver), from whose name the name of the entire country was subsequently derived. After the liberation of the country from Spanish troops (1811-1826), in order not to remember the Spaniards, the name of the country was Latinized (silver - argentum in Latin), and it has survived to this day...

Since the middle of the 20th century, silver has ceased to be a metal from which coins were only minted. The emergence and development of industries such as photography, electrical engineering, and radio electronics led to a sharp increase in demand for silver and its withdrawal from monetary circulation.

This metal has the highest electrical conductivity among metals, as well as good ductility and a low melting point. Silver is chemically inactive, and in the presence of hydrogen sulfide it darkens. And as mentioned earlier, silver has bactericidal properties, which is a big advantage compared to other metals. Also, the main advantage of silver is that it is much more abundant than gold. However... There may be a shortage of silver and an increase in the price of silver

Approximate calculations showed that in total more than 700 thousand tons of this noble metal were extracted from the depths. And in the future, high demand for silver will remain stable in the world. There is already a shortage of silver, which is holding back development latest technologies. It is likely that the uses for silver will decline in the future, as limited supplies will lead to such high prices that silver substitutes will be used wherever possible. We can conclude that investing and storing money in silver is profitable, reliable and safe.

Opening. Production

Names from the word silver

Possible shortage silver and rising prices

History of the canteen silver

origin of name

Being in nature

Physical properties

Silver nugget

Chemical properties

Biochemistry

Application

Silver water

In medicine

Physiological action

Biological activity

Silver plate

Beneficial effects on the human body

Properties

Caring for trade items

Cleaning and Cleaning

Cutlery care

Connections

Monovalent silver compounds

Inorganic compounds

Coordination compounds

Bivalent silver compounds

Inorganic compounds

Coordination compounds

Trivalent silver compounds

IN Russian Federation The first silver was mined in 1704 at the Nerchinsk mines in Transbaikalia. A certain amount was mined in Altai. It was only in the middle of the 20th century that numerous deposits in the Far East were developed.

In 2008, a total of 20,900 tons of Silver were mined. The leader in production is the Peruvian Republic (3,600 tons), followed by Mexico (3,000 tons), (2,600 tons), the Republic of Chile (2,000 tons), (1,800 tons), Poland (1,300 tons), the USA (1 120 t), Canada (800 t).

For 2008, the leader in Silver production in the Russian Federation is Organization Polymetal, which produced 535 tons in 2008.

World reserves of Silver are estimated at 570,000 tons.

Silver plate

The minimum concentration of Silver in water (0.01 mg/l) is sufficient to destroy more than 260 varieties of pathogenic microbes, viruses and fungi. For comparison: a regular antibiotic kills about 6 types of microbes...

Silverware is a sign of wealth and health. Thus, it becomes clear that silverware is not only a sign of prosperity or wealth, but also a means of prevention and health!

From history: it is known that 2500 years before the birth of Christ, Egyptian warriors used Silver to treat their wounds - they applied very thin silver plates to them, and the wounds healed quickly.

The Persian king Cyrus, according to Herodotus, during long campaigns stored water only in silver barrels. Thus, he managed to avoid many diseases common at that time. IN late XIX century, the Swiss botanist Karl Nägeli established that under the influence of Silver introduced into water, all harmful microorganisms in it die. Silver ions prevent the proliferation of pathogenic bacteria, viruses and fungi.

Beneficial effects on the human body Currently, Silver is considered not just as a Metal capable of killing microbes, but as a trace element that is necessary and permanent integral part tissues of any animal and plant organism.

For centuries, the excellent antibacterial properties of Silver have been used in the treatment of many inflammatory diseases. The ancient Greeks and Romans stored liquids in silver vessels, knowing that in this way their properties are improved. Silver has been traditionally used in folk medicine in Eastern countries for over a thousand years. The first American settlers, moving through the Wild West, stored milk in vessels with silver Dollar at the bottom. It is no coincidence that in church ceremonies they use silver cups- this prevents the spread of infections among the congregation.

Until now, the use of silver cutlery is considered not only prestigious, but also hygienic. On all space shuttles, the water is enriched with Silver in preparation for consumption; Airliners use silver water filters. Silver is increasingly used for water purification in swimming pools - it does not irritate mucous membranes and is more effective as an antiseptic. In Japan, the air is purified with the help of Silver. IN Switzerland Silver filters are widely used in homes and offices.

Founder scientific study The mechanism of action of Silver on a microbial cell is the Swiss botanist Carl Nigeli, who in the 80s of the 19th century established that the interaction not of the Metal itself, but of its ions with the cells of microorganisms causes their death. He called this phenomenon oligodynamy (from the Greek “oligos” - small, trace, and “dynamos” - action, i.e. the action of traces). The scientist proved that Silver exhibits an oligodynamic effect only in dissolved (ionized) form.

The German scientist Vincent, comparing the activity of some Metals, found that Silver has the most powerful bactericidal effect, Copper and Gold have less.

Big Contribution into the study of the antimicrobial properties of silver water, its use for disinfection drinking water and food products contributed by academician L.A. Kulsky. His experiments, and later the works of other researchers, proved that it is metal ions and their dissociated compounds (substances that can disintegrate into ions) that cause the death of microorganisms. Medical and biological studies have established that the bactericidal properties of Silver are explained by the unique ability of its ions to block the enzymes of pathogenic microorganisms, which leads to their death. At the same time, microorganisms necessary for human life are preserved.

It is known that due to the bactericidal properties of Silver, dishes, made and served by prominent military leaders, helped them practically not suffer from intestinal diseases during military campaigns. It is not without reason that since the middle of the 13th century, Silver has become a traditional material for making tableware. Due to physical and chemical properties Silver: excellent malleability, ductility, white color, bactericidal properties. Dishes made from Silver became a real jewel. Luxurious bowls, trays, and sets served not only as items for festive table settings, but also as worthy gifts, subsequently becoming exhibits in museum collections. In addition, silverware has been considered a symbol of wealth and respectability for many centuries. It is a known fact that in the family of Count Orlov, one of Catherine II’s favorites, there was service, consisting of 3275 silver objects, the production of which took more than 2 tons of Silver! The masters decorated the Silver itself with weaves made from it, niello, filigree, granulation, and enamel.

Doctors have proven the positive effect of Silver on Processes life activity of humans and animals. Silver significantly increases the specific defense of the human body, which is especially useful when the body’s immune activity is low.

Properties

Pure Silver is a relatively soft and ductile Metal: from 1 g of Silver you can draw the thinnest wire almost 2 km long! Silver is a rather heavy metal: in density (10.5 g/cm3) it is only slightly inferior to Lead. In terms of electrical and thermal conductivity, Silver has no equal (that’s why a silver spoon in a glass of hot tea heats up quickly). Silver melts at a relatively low temperature (962° C), which greatly facilitates its processing. Silver is easily alloyed with many Metals; small additions of Cuprum make it harder, suitable for the manufacture of various Trade Items.

“Silver does not oxidize in air,” wrote D.I. Mendeleev in his textbook Fundamentals of Chemistry, “and therefore is classified as a so-called noble metal. It has a white color, much purer than all other known Metals, especially when it represents chemical purity... Chemically pure Silver is so soft that it wears off very easily...” But although Silver does not directly react with oxygen, it can dissolve significant quantities of this gas. Even solid Silver at a temperature of 450°C is capable of absorbing five times the volume of oxygen. Significantly more oxygen (up to 20 volumes per 1 volume of Silver) dissolves in liquid Metal. This property of Silver leads to the beautiful (and dangerous) phenomenon of Silver spattering, which has been known since ancient times. If molten Silver has absorbed significant amounts of oxygen, then the solidification of the Metal is accompanied by the release large quantity gas The pressure of the released oxygen breaks the crust on the surface of the solidifying Silver, often with great force. The result is a sudden explosive spattering of Metal. At 170° C, silver in air is covered with a thin film of Ag2O oxide, and under the influence of ozone, higher oxides Ag2O2 and Ag2O3 are formed. But Silver is especially “afraid” of iodine, for example, tincture of iodine and hydrogen sulfide. Many homes have silver (or silver-plated) items of trade - old coins, spoons, forks, cup holders, rings, chains, and other jewelry. Over time, they often fade and may even turn black. The reason is the action of hydrogen sulfide. Its source can be not only rotten eggs, but also rubber and some polymers. In the presence of moisture, Silver easily reacts with hydrogen sulfide to form a thin film of sulfide on the surface: 4Ag + 2H2S + O2 = 2Ag2S + 2H2O; Due to the unevenness of the surface and the play of light, such a film sometimes appears rainbow-colored. Gradually the film thickens, darkens, turns brown, and then black. Silver sulfide is not destroyed by strong heating and does not dissolve in acids and alkalis. A not very thick film can be removed mechanically by polishing the object with toothpaste or powder with soapy water...

Caring for Silver Trade Items

It is no secret that even pure Silver darkens under the influence of conditions environment and requires periodic cleaning. Silver easily reacts with hydrogen sulfide, especially in a humid environment, becoming coated with a superficial “scarlet silver.” And since hydrogen sulfide is constantly present in the air, silver darkens over time when exposed to air. But don’t be sad that your favorite piece of jewelry has lost its presentation. Here are several ways in which you can restore the shine to jewelry Items of trade. For example, the Trade Item can be washed in warm water with baking soda (50g per 1 liter of water) or soapy water (or household detergent without bleaching effect) with ammonia (1 tablespoon per 1 liter of water). After washing, the Trade Item is rinsed and wiped dry with a soft cloth. You can get rid of mold stains on silver items by rubbing them with a cloth moistened with a heated 6% vinegar solution. Decorate with acid enamel using a cotton swab with a mixture of tooth powder and a few drops of ammonia applied to it. It would also be useful to remind you about the rules for storing jewelry Items of trade. To avoid the appearance of dark spots on jewelry from touching wet skin, it is necessary to immediately wipe it with a dry flannel when removing the jewelry.

When performing various economic works, and also in case of contact with chemicals, it is recommended to remove rings, bracelets, and other jewelry Items of trade, which protects them from damage and contamination. It is also recommended to remove jewelry when using cosmetics prepared on the basis of mercury and sulfur salts (it easily forms black sulfur compounds with Silver). Dark stains on silver trade items are caused by iodine. Jewelry Items of trade should be stored in cases in a dry place. To keep your silver items shiny longer, store them so that they do not touch each other or other jewelry.

By purchasing cutlery from Silver, you also take care of your health. Due to its high bactericidal properties, Silver protects against many infectious, gastric and pulmonary diseases. This Metal strengthens the heart, improves vision, helps with urological diseases, and quenches thirst. A well-known ancient custom is to store water in silver vessels.

Caring for your Silver is very important to maintainIsilver items in beautiful condition. On this page you can read several methods for cleaning and cleaning Silver and silver plated items.

Cleaning and Cleaning Silver

Clear Silver from dark spots you can ammonia solution!

To remove dark deposits from silver, silver-plated items of trade, cutlery, you need to wash them in warm soapy water, and then clean them with a soft cloth with a mixture of powdered chalk (tooth powder) with a few drops applied to it ammonia, then wash clean water and wipe. Also the shine is strong Tarnished Silver Trade Items can be restored if you wash them first with any detergent, and then with a solution of sodium hyposulfite (20 g of photographic sodium hyposulfite per 100 ml of water) and warm water.

You can refresh silver, silver-plated and cupronickel Items of trade by washing them in warm water with baking soda (17 g per 1 liter of water) or in warm soapy water with the addition of ammonia (2 tablespoons per 1 liter of water), then rinse with clean water and wipe .

You can get rid of mold stains on silver items by wiping them with a cloth moistened with a heated 6% vinegar solution.

In order for jewelry to delight you with glaammonia, you also need to take care of it. Firstly, in order to protect jewelry items from contamination and damage, they must be removed during household work, as well as when using cosmetics.

If a silver chain or ring is covered with a dark coating, wash the jewelry in warm soapy water, then clean it with a soft cloth soaked in a mixture of ammonia and tooth powder, wash again with clean warm water and wipe.

Cutlery care

For Trade Items with silver or gold plating required special conditions care Silver-plated Trade Items should not come into contact with rubber, as it contains sulfur, which is a catalyst for the self-oxidation of Silver. It should be remembered that Silver and Gold are very soft materials and are easily scratched, so coated cutlery requires careful handling. Cutlery coated with precious metals should be cleaned regularly with specialized products. Silver plate should be stored in specially designed cases in a cool place. The mirror surface of polished Silver and its original color are preserved for a long time if it is carefully wiped or dried after each wash or rinse. If a slight dark deposit appears on the surface of the Items of Trade, it can be removed by washing in warm water with the addition of baking soda (50 grams per 1 liter). After this, the silver is wiped dry with a soft cloth. In case of severe darkening or contamination of the surface of the Trade Items, it is necessary to use special means for Silver cleaning(for example, "Dipping Bath for Argentum" by German Companies"Delu" or its Italian analogue of the Silbo Company. Of the domestic cleaning products, the most effective is “FLUR” - a unique development of NIIyuvelirprom, part of OJSC Russian Gems. If there is a gold decorative coating on the surface of Silver tableware, you must especially carefully monitor its safety: applied in a thin layer, it can be damaged or destroyed by strong friction or heating of the Trade Item to a temperature of 100°C. Mechanical deformation of tableware items (bending, breaking, etc.) must not be allowed, since in this case the protective and decorative coatings on these Trade Items may be destroyed and peeled off from the Silver.

Connections

There are known compounds in which Silver is mono-, bi- and trivalent. In contrast to stable compounds of monovalent Silver, compounds of divalent and trivalent Silver are few in number and are not very stable.

Compounds of monovalent silver

Numerous stable compounds (simple and coordination) of monovalent Silver are known. The monovalent Silver ion Ag+ with a radius of 1.55 (diamagnetic, colorless, hydrated, easily polarized, is an oxidizing agent (easily reduced by various reducing agents to metallic Silver) and plays the role of a catalyst in the oxidation reaction of manganese (II) ion with the anion: S202-8. Most Silver (I) compounds ) is poorly soluble in water. Nitrate, perchlorate, chlorate, fluoride are soluble in water, and Silver acetate and sulfate are partially soluble. Silver (I) salts are white or slightly yellowish (when

annon salt is colorless). Due to the deformability of the electron shells of the silver(I) ion, some of its compounds with colorless anions are colored. Many of the Silver(I) compounds turn gray when exposed to sunlight, which is due to the process of reduction to metallic Silver. Silver(I) salts have little tendency to hydrolysis. When Silver salts are heated with a mixture of sodium carbonate and coal, metallic Silver is formed:

2AgNO3 + Na2CO3 + 4C = 2Ag + 2NaNO2 + 5CO

Numerous coordination compounds of silver(I) are known, in which the coordination number of Silver is 2, 3 and 4.

Inorganic compounds

Silver oxide, Ag2O, is obtained by treating solutions of AgNO3 with alkalis or solutions of hydroxides of alkaline earth metals:

2AgNO3 + 2KOH = Ag2O + 2KNO3 + H2O

Silver oxide is a diamagnetic crystalline powder (cubic crystals) of brown-black color with a density of 7.1 - 7.4 g/cm3, which slowly turns black in the light, releasing oxygen, and decomposes into elements when heated to +200°C:

Hydrogen, carbon monoxide, hydrogen peroxide and many metals

reduce Silver oxide in an aqueous suspension to metallic Silver. When Ag2O is oxidized with ozone, silver(II) oxide is formed. Silver(I) oxide is dissolved in hydrofluoric and nitric acids, ammonium salts, in solutions of alkali metal cyanides, in ammonia, etc.

Ag2O + 2HF = 2AgF + H2O

Ag2O + 2HNO3 = 2AgNO3

Ag2O + 2(NH4)2CO3 = 2CO3 + 2H2O +CO2

Ag2O + 4KCN + H2O = K + 2KOH

Ag2O + 4NH4OH = 2OH + 3H2O or

Ag2O + 4NH3 + H2O = 2OH

When stored, diammine silver hydroxide OH (which is a soluble base with oxidizing properties) turns into the explosive Silver imide;

2OH = Ag2NH + 3NH3 + 2H2O

Solutions of alkali metal chlorides convert silver(I) oxide into silver(I) chloride, and when excess HgI2 acts on Ag2O, Ag2 is formed. Silver oxide is an energetic oxidizing agent towards chromium(III) compounds, aldehydes and halogen derivatives of hydrocarbons:

5Ag2O + Cr2O3= 2Ag2CrO4 + 6Ag

3Ag2O + 2Cr(OH)3 + 4NaOH = 2Na2GrO4 + 6Ag + 5H2O

The oxidation of halogenated hydrocarbons leads to hydrocarbons of alcohols, and the oxidation of aldehydes leads to the corresponding acids. Solutions of alkali metal sulfides and aqueous suspensions of sulfides heavy metals convert Ag2O oxide into Ag2S sulfide. acids and suspensions of Silver oxide are used in medicine as an antiseptic

2Ag + F2 = 2AgF + 97.4 kcal

Ag2CO3 + 2HF = 2AgF + H2O + CO2

Ag2O + 2HF = 2AgF + H2O

Ag = AgF + BF3

Isolation of AgF crystals from an aqueous solution is carried out by concentration in vacuum in the dark. The AgF compound is colorless face-centered cubic crystals that diffuse in air with a density of 5.85 g/cm3 and a melting point of +435°C; Silver fluoride is poorly soluble in alcohol, easily soluble in water (unlike other Silver halides) and in ammonia; it should not be stored in glass containers as it will destroy the glass. Under the influence of water vapor and hydrogen upon heating, Silver fluoride is reduced to metallic Silver:

2Ag+ Н2O = 2Ag + 2HF + Ѕ O2

2AgF + H2 = 2Ag + 2HF

Ultraviolet rays cause the transformation of Silver fluoride into Ag2F semifluoride. An aqueous solution of Silver fluoride is used to disinfect drinking water.

Crystalline hydrates AgF .nH2O (where n is 1, 2, 4) and fluoroacids H, H3 are known. AgF monohydrate. H2O precipitates in the form of light yellow cubic crystals when a solution of anhydrous AgF in water is evaporated in vacuum. AgF dihydrate. 2H20, which is solid colorless prismatic crystals with a melting point of +42°C, precipitates in ammonia-centered AgF solutions. AgF crystals precipitate from the solution obtained by dissolving Ag2O in 20% hydrofluoric acid. 4N20. When a solution of A-acid is cooled, colorless crystals of H3 precipitate, which at 0°C in a stream of air turn into white crystals of H. Silver chloride, AgCl, occurs in nature in the form of the mineral kerargyrite and can be obtained by treating metallic Silver with chlorine water, reacting the elements at high temperature, the effect of gaseous HCl on Silver (above +1150°C), treatment of Silver with hydrochloric acid in the presence of air (oxygen or other oxidizing agent), the effect of soluble chlorides on Silver, treatment of solutions of Silver salts with hydrochloric acid or a solution of any chloride.

The AgCl compound is diamagnetic white cubic faceted crystals with m.p. +455°C, etc. boil. +155 Silver ammonia oxide dissolves in solutions of chlorides (NaCl, KС1, NH4C1, CaС12, MnCl2). cyanide, thiosulfate hydrogen alkaline metals and ammonia with the formation of soluble and colorless coordination compounds

AgCl + KCl = K

AgCl + 2Na2S2O3 + Na3 + NaCl

AgCl + 2KCN = K + KCl

AgCl + 2NH3 = Cl

Under the influence of light, Silver chloride is reduced (coloring violet and then black) with the release of ribs and chlorine: AgCl = Ag + 1/2Cl2. The use of Silver chloride in photographic films is based on this reaction.

Silver bromide, AgBr, occurs naturally as the mineral bromargyrite. In the laboratory, it can be obtained in the dark by treating a solution of AgNO3 with a solution of HBr (or alkali metal bromide) or by direct interaction of bromine with metallic Silver. AgBr is produced in the dark to prevent photoreduction:

AgNO3 + KBr = AgBr + KNO3

Ag + 1/2Br2 = AgBr + 27.4 kcal

The AgBr compound can exist either in colloidal form or in the form of diamagnetic yellow cubic face-centered crystals with a density of 6.47 g/cm3, mp. +434°C, etc. boil. +15370C. Silver bromide is poorly soluble in water and dissolves in ammonia, alkali metal sulfates and conc. Acid pan>when heated:

AgBr + 2NH4OH = Br + 2H2O

2AgBr + acidAg2SO4 + 2HBr

AgBr + 2Na2S2O3 -> Na3 + NaBr

Silver bromide is more sensitive to light than Silver chloride, and iodine is decomposed into elements by the action of light: AgBr = Ag +1/2Br2. Silver bromide is reduced by Zinc in an acidic environment or by Metals (such as Copper) when heated and by ammonia with anhydrous sodium carbonate:

2AgBr + Na2CO3 = 2Ag + 2NaBr + CO2

In the cold, AgBr absorbs ammonia, and various adducts can form: AgBr. NH3, 2AgBr. 3NH3, AgBr. 3NH3. Silver bromide is used for the manufacture of photographic films and as a catalyst in the production of monocarboxylic fatty acids or olefins using the Grignard reagent. Silver iodide, AgI. found in nature in the form of the Mineral iodine, in the laboratory can be obtained (in the dark) by a reverse solution of AgNO3 with a solution of HI or iodide of an alkali metal, by the direct reaction of iodine vapor with metallic Silver, chloride or bromide of Silver when heated, by the action of HI on metallic Silver in the cold.

AgNO3 + HI = Agl + HNO3

Ag + V2I2 = Agl + 29.3 kcal

AgNO3 + KI = Agl + KNO3

Ag + HI = Agl + l/2H2

Silver iodide can exist either as transparent birefringent lemon yellow hexagonal prismatic crystals or as birefringent red octahedra.

AgNO3 + KCN = AgCN+KNO3

Cyammonium kernels are colorless rhombohedral crystals with a density of 3.95 g/cm3, etc. +320..350°C. It is poorly soluble in water, dissolves in ammonia or solutions of ammonium salts, cyanides and thiosulfates of alkali metals with the formation of coordination compounds.

AgCN + 2NH4OH = CN +2H2O

AgCN + KCN = K

Acetic acid and hydrogen sulfide react with dicyano-argentates Me1 according to the equations

K + HNO3 = AgCN + KNO3 + HCN

2K + 2H2S = Ag2S + K2S + 4HCN

When K is treated with Silver nitrate, Silver dicyanoargentate Ag is formed, which is a dimeric form of Silver monocyanide. Cyanoargentates of types Me12 and Me12 are known. Silver oxalate is a white monoclinic acid metal with a density of 5.029 g/cm3, it is poorly soluble in water, sensitive to light, and decomposes when heated to +100°C. At +140oC Ag2C2O4 decomposes by explosion.

Silver Periods . The following Silver periodates are known: AgIO4 - orange, Ag2H3IO6 - lemon yellow. Ag3 IO5 and Ag5IO6 are black.

Coordination compounds

Most simple compounds of monovalent Silver with inorganic and organic reagents form coordination compounds. Thanks to the formation of coordination compounds, many silver compounds that are poorly soluble in water are converted into easily soluble ones. Silver can have coordination numbers of 2, 3, 4 and 6. Numerous coordination compounds are known in which neutral molecules of ammonia or amines (mono- or dimethylamine, pyridine, ethylenediamp. aniline, etc.) are coordinated around the central ion of Silver. Under the action of ammonia or various organic amines into oxide, hydroxide, nitrate, sulfate, carbonate of Silver are formed by an ammonia complex cation, for example +, +, +, +,+. The stability of complex Silver cations is lower than the stability of the corresponding copper(II) cations. When Silver halides (AgCl, AgBr, AgI) are dissolved in solutions of alkali metal halides, pseudohalides or thiosulfates, water-soluble coordination compounds containing complex anions are formed, for example -, 2-, 3-, Ag Br3]2-, etc. n-Dforms a purple precipitate with concentrated solutions of Silver salts. With dilute solutions of Silver salts, dimethylaminobenzyl-idenerhodamine does not form a precipitate, but only colors the solution intensely purple.

Bivalent Silver compounds

Few compounds of divalent silver are known. They are characterized by low stability and the ability to decompose with water, releasing oxygen. Inorganic compounds

Silver oxide, AgO, is obtained by the action of ozone on metallic Silver or on Ag2O, AgNO3 or Ag2SO4, by treating a solution of AgNO3 with a solution of K2S2O8, by treating an alkaline suspension of Ag2O with potassium permanganate, by anodic oxidation of metallic Silver using a dilute solution of H2SO4 or NaOH as an electrolyte.

Ag2O + O3 = 2AgO + O2

2AgNO3 + K2S2O8 + 4KOH = 2AgO + 2K2SO4 + 2KNO3 + 2H2O

Ag2O + 2KMnO4 + 2KOH = 2AgO + 2K2MnO4 + H2O

Treatment of silver compounds with K2S2O8 in weakly ammonia and in the presence of pyridine leads to the formation of an orange crystalline precipitate of ammonia 2O8. Silver oxide is a diamagnetic grayish black crystalline powder with a density of 7.48 g/cm3. It is soluble in H2SO4, HClO4 and conc. HNO3, stable at ordinary temperatures, decomposes into elements when heated to +100oC, is an energetic oxidizing agent in relation to SO2, NH3 Me+NO2, and has semiconductor properties. Silver fluoride, AgF2, is obtained by the action of fluorine gas on metallic Silver at +250..300°C or on silver(I) halides at +200..300°C.

Ag + F2 = AgF2 + 84.5 cal

Silver fluoride is a paramagnetic brown-black powder with a mp. +690°C. It decomposes under the influence of water or moist air and has an oxidizing effect towards iodides, alcohol, chromium(III) and manganese(II) salts.

6AgF2 + 3Н2O = 6AgF + 6HF + O3

Silver sulfide, AgS, is formed as a brown precipitate when a solution of AgNO3 in beisoylpropyl is treated with a solution of Sulfur in carbon disulfide. Silver nitrate, Ag(NO3)2, is obtained by oxidation of Ag(NO3)2 with ozone. These are colorless crystals that decompose with water: 4Ag(NO3)2 + 2H2O = 4AgNO3 + 4HNO3 + O2

Coordination compounds

A number of coordination compounds of divalent Silver of types X2 and X2 are known (where Am == phenanthroline C12H8N2, dipyridyl

C10H8N2 and X = NO-3, СlO-3, ClO-4)

Trivalent Silver Compounds

A small number of trivalent compounds are known (ribs, for example Ag2O3, K6H .10 H2O, K7, Na7H2 .14H2 O, etc. Silver oxide, Ag2O3, is formed in a mixture with silver(II) oxide - anodic oxidation of Silver or under the action of fluorine (or perosulfate ) to silver(I) salt.The black crystalline mixture of Ag2O3 AgO is unstable, has oxidizing properties and, when slightly heated, turns into AgO.

Diorthoperiodate argeitates (III), MeI6H.nH2O, are orange-colored diamagnetic salts with beautifully shaped crystals. NH3x is considered as derivatives of the hypothetical acid H7. When a mixture of aqueous solutions of AgNO3, K5IO6 and KOH is oxidized with potassium persulphate K2S2O8, a brown solution is formed, from which, upon concentration by slow evaporation, orange crystals K6H.10H2O precipitate, and upon rapid evaporation, K7.KOH.8H2O. Treatment of the K6H compound with sodium carbonate results in the precipitation of orange-yellow crystals of Na5KH.16H2O.

Diorthotellurargentates Me+6H3.nH2O Me+7H2.nH2O are beautifully crystallizing yellow diamagnetic salts - derivatives of hypotic acid H9.

Oxidation of an aqueous solution of a mixture of Ag2S04, Na2CO3 and TeO2 with potassium peroxosulfate K2S2O5 leads to the formation of a brown solution, from which, upon concentration by isothermal evaporation, yellow crystals of Na6H3.18H20 precipitate. When using large quantities of sodium corbanate, Na7H2.14H2 crystals precipitate

Why is the Sample needed and when did the Samples appear?

The sample is guaranteed by the state, for which the Items of trade must undergo an assay (sampling and analysis) and stamps of hallmarks are applied to them. Ingots of noble metals are hallmarked by the fineness determined in the alloy. Orders, award medals and coins are not subject to hallmarking, although the quality of their alloys is strictly regulated and controlled. Control For hallmarks of alloys and Trade Items and hallmarking in the USSR is carried out by the Assay Supervision Inspectorates.

In countries where state assay supervision is established, Trade Items of trade made of precious metals without imprints of hallmarks are prohibited, and counterfeiting of hallmarks is punishable by law. To mark Trade Items, hallmarks of various shapes and designs are used. The design of the mark (usually the emblem of a Country, acid, etc.) is combined with the Assay numbers (for example, ) or with conventional numbers 1, 2, etc., where each number corresponds to a specific Assay (for example, Austria, Argentina, Bulgaria, Hungary, Cameroon, the Netherlands, Poland, Romania, Czechoslovakia, Yugoslavia, Mexico); hieroglyphs (Egypt, Tunisia, ). Sometimes the Hallmark indicates a mark only in the form of numbers of the metric Hallmark (Mongolia). In the USSR and on silver objects of that time, the hallmark consists of 3 elements: an emblem (a hammer and sickle against the background of a five-pointed star); three-digit digits of the metric standard; code (in the form of a letter) assigned to a specific acid inspection inspection.

Branding of jewelry and household items of trade has been known since the Middle Ages (for example, in Britain and Italy from the 15th century, in France from the 16th century). In a number of countries, branding was introduced in the 20th century (for example, in Canada since 1913, Australia since 1923). In some Countries, although jewelry and household Items of Trade made of precious Metals are branded (usually by the manufacturing companies of the Items of Trade), they Control for the Breakdown on the part of the State is not obligatory or weak (for example, Australia, Belgium, Italy, Canada, Malta, USA, Germany, Sweden).

In the Russian Federation, state branding of Trade Items was legalized: silver - in 1613, gold - in 1700; in the USSR: platinum - in 1927, palladium - in 1956.

- – a chemical element, a precious metal that is a commodity. Typically represented by the symbol Ag, which comes from the Latin word argentum. It may also appear in stock reports English word silver, meaning... ... Banking Encyclopedia

silver- noun, p., used compare often Morphology: (no) what? silver, what? silver, (I see) what? silver, what? silver, what about? about silver 1. Silver is a noble metal of grayish white color with luster, which is used for making... ... Dmitriev's Explanatory Dictionary

silver- Ukrainian silver, sriblo, blr. silver, other Russian silver (Io. Klim., XII century, Grig. Naz., according to Shakhmatov, Essay 200 et seq.), from where, through early assimilation of vowels - other Russian. silver (Izborn. St. 1073, gram. Mstislav 1130, Turovsk. Gospel ... Etymological Dictionary of the Russian Language by Max Vasmer

SILVER- SILVER, silver, plural. No. Wed 1. Precious soft metal of grayish white color with shine. Pure silver. Silver alloys. || collected Products made from this metal (dishes, jewelry, etc.). Silver plate. Tea silver. “And he has a lot of good things... ... Ushakov's Explanatory Dictionary

SILVER- SILVER, Argentum (Ag), chemical. element, metal, at. V. 107.880, is in the 7th row of group I of Mendeleev’s periodic table of elements. S. is found in nature in native form, as well as in compounds with sulfur, selenium, tellurium, arsenic and... ... Great Medical Encyclopedia

silver- SILVER1, a, cf Chemical element, grayish white shiny precious metal. Silver is used mainly in the form of silver alloys for the manufacture of jewelry and tableware, for coinage and for various technical... ... Explanatory dictionary of Russian nouns

SILVER- (Argentum), Ag, chemical element of group I of the periodic table, atomic number 47, atomic mass 107.8682; noble metal, melting point 961.93shC. Used in film and photographic production. Silver and its alloys are used in electrical engineering and... ... Modern encyclopedia

SILVER- (lat. Argrentum) Ag, chemical element of group I of the periodic system of Mendeleev, atomic number 47, atomic mass 107.8682. White metal, malleable, ductile; density 10.5 g/cm³, melting point 961.9 °C. One of the scarce elements. It has… … Big Encyclopedic Dictionary

SILVER- (symbol Ag), white chemical element of the second row of TRANSITION ELEMENTS, metal. Found in ARGENTITES (sulfide) and horn silver (SILVER CHLORIDE), also mined as a by-product of copper and lead refining. The main producer of silver... ... Scientific and technical encyclopedic dictionary Read more