Platinum chemistry formula. Platinum: where is it used and what unique properties it has

”Acquired due to its external similarity with silver. Silver in Spanish is "plata", and "platina" is translated as small, light silver, "silver." Platinum has a silvery white color, sometimes with a grayish tint. It can be found in nature both in pure form, as a nugget, and in the composition of the ore. The density of platinum is also very high, 21.45 g / cc. see For comparison, the density of gold is 19.3 g / cu. cm.

If platinum itself is silvery-white, then why are its types found in a slightly different color? The thing is that platinum nuggets are rarely "pure", as a rule, they contain impurities that determine the color of the metal. The impurities may include iron, copper, iridium, palladium, and other metals. Additionally, sometimes jewelers themselves create alloys of platinum with other precious metals.

For example, for frames precious stones platinum is often used, which contains silver, gold or copper. Accordingly, the tint of the metal can be yellowish or reddish. Tungsten and palladium, which can also be components of a platinum alloy, change its color to bright white or silvery gray.

Samples of platinum 850, 900, 950 are popular in Russia. Sample 950 means that to create jewelry a composition was taken, in which 95% falls on, and 5% on various impurities.

Platinum 850 and 900 samples are usually used not for jewelry, but for technical purposes, for example, for medical purposes.

Due to the fact that platinum is most often in the form of alloys with additional components, this metal is almost impossible to distinguish by eye from silver or white gold. You should focus precisely on, milking platinum is "PT 950", "PT 900", "PT 850". But the fineness of 750 already means that you see not platinum, but gold.

Platinum history

For a long time, platinum was unpopular; it was valued twice as low as silver. This is explained by the fact that Spanish travelers who discovered it in South America noticed that platinum is very refractory. This was a serious barrier to the use of the metal in those days, so platinum was recognized as of little use.

But as soon as the jewelers noticed how well platinum is alloyed with gold, its value increased markedly, but only among the jewelers themselves, who mixed this metal with gold, which came out cheaper than pure gold, and was not inferior in density to it. But over time, this "technology" was discovered, platinum was banned from being imported into Spain, and its reserves were dumped into the sea.

In the past, platinum was highly prized by the ancient Egyptians and Incas.

In France, platinum was more fortunate. Louis XVI considered it the only metal worthy of royalty. The reason is that platinum is almost impossible to scratch, it does not corrode. Any chemicals that damage gold and silver will leave platinum intact. Platinum bypasses all other precious metals in strength, it can only be affected by aqua regia.

Platinum- a mineral, natural Pt from the platinum group of the class of native elements, usually contains Pd, Ir, Fe, Ni. Pure platinum is very rare, most of the samples are represented by the ferrous variety (polyxene), and often by intermetallic compounds: isoferroplatinum (Pt, Fe) 3 Fe and tetraferroplatinum (Pt, Fe) Fe. Platinum, represented by polyxene, is the most abundant platinum-group mineral in the earth's crust.

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STRUCTURE

The crystal lattice of platinum belongs to the cubic system. The cyclohexene molecule has the shape of a regular hexagon. In the considered reaction system, the atomic structure of the catalyst and the reacting molecules have one common quality - the elements of symmetry of the third order. In a platinum crystal, such an arrangement of atoms is inherent only in the octahedral face. Platinum atoms are located in the nodes. a = 0.392 nm, Z = 4, space group Fm3m

PROPERTIES

Polyxene color ranges from silver white to steel black. The line is metallic steel gray. Typical metallic luster. The reflectivity in polished thin sections is high - 65-70.
Hardness 4-4.5, in iridium-rich varieties - up to 6-7. Possesses malleability. The fracture is hooked. Cleavage is usually absent. Ud. weight-15-19. The relationship between the reduced specific gravity and the presence of voids occupied by natural gases, as well as inclusions of foreign minerals, was noted. Magnetic, paramagnetic. Conducts electricity well. Platinum is one of the most inert metals. It is insoluble in acids and alkalis, with the exception of aqua regia. Platinum also reacts directly with bromine, dissolving in it.

When heated, platinum becomes more reactive. It reacts with peroxides, and upon contact with atmospheric oxygen, with alkalis. Thin platinum wire burns in fluorine with emission a large number heat. Reactions with other non-metals (chlorine, sulfur, phosphorus) are less active. When heated more strongly, platinum reacts with carbon and silicon, forming solid solutions, similar to the metals of the iron group.

RESERVES AND PRODUCTION

Platinum is one of the rarest metals: its average content in the earth's crust (clarke) is 5 · 10 −7% by mass. Even the so-called native platinum is an alloy containing 75 to 92 percent platinum, up to 20 percent iron, as well as iridium, palladium, rhodium, osmium, less often copper and nickel.

The world's explored reserves of platinum group metals amount to about 80,000 tons and are distributed mainly between South Africa (87.5%), Russia (8.3%) and the United States (2.5%).

In Russia, the main deposits of platinum group metals are: Oktyabrskoye, Talnakhskoye and Norilsk-1 sulfide-copper-nickel in the Krasnoyarsk Territory in the Norilsk region (more than 99% of the explored and more than 94% of the estimated Russian reserves), Fedorova Tundra (the Bolshoi Ikhtegipakhk site), sulfide copper-nickel in the Murmansk region, as well as alluvial Conder in the Khabarovsk Territory, Levtyrinyvayam in the Kamchatka Territory, the Lobva and Vyisko-Isovskoye rivers in the Sverdlovsk Region. The largest platinum nugget found in Russia is the "Ural Giant" weighing 7860.5 g, discovered in 1904. at the Isov mine.

Native platinum is mined in the mines, less rich are the placer deposits of platinum, which are explored mainly by the method of schlich sampling.

The production of platinum in powder form began in 1805 by the English scientist W.H. Wollaston from South American ore.
Today, platinum is obtained from a concentrate of platinum metals. The concentrate is dissolved in aqua regia, after which ethanol and sugar syrup are added to remove excess HNO 3. In this case, iridium and palladium are reduced to Ir 3+ and Pd 2+. By the subsequent addition of ammonium chloride, ammonium hexachloroplatinate (IV) (NH 4) 2 PtCl 6 is isolated. The dried precipitate is calcined at 800-1000 ° C
The thus obtained spongy platinum is subjected to further purification by redissolving in aqua regia, precipitating (NH 4) 2 PtCl 6 and calcining the residue. Then the refined spongy platinum is melted into ingots. When reducing solutions of platinum salts by chemical or electrochemical methods, finely dispersed platinum is obtained - platinum black.

ORIGIN

Platinum group minerals are found in most cases in typical igneous deposits genetically related to ultrabasic igneous rocks. These minerals in ore bodies are released among the latter (after silicates and oxides) at the moments corresponding to the hydrothermal stage of the magmatic process. Platinum minerals, poor in palladium (polyxene, iridous platinum, etc.), are found in deposits among dunites - olivine feldspar-free rocks rich in magnesia and poor in silica. At the same time, paragenetically, they are extremely closely related to Cr-spinels. Palladium in nickel-palladium platinum is predominantly distributed in the main igneous rocks (norites, gabbronorites) and is usually associated with sulfides: pyrrhotite, chalcopyrite, and pentlandite.
Under exogenous conditions, in the process of destruction of primary deposits and rocks, platinum-bearing placers are formed. Most of the minerals of the platinum subgroup are chemically stable under these conditions. Platinum in placers is found in the form of nuggets, scales, plates, cakes, nodules, as well as skeletal forms and spongy excretions ranging in size from 0.05 to 5 mm., Sometimes up to 12 mm. Flattened and lamellar grains of platinum indicate significant distance from primary sources and redeposition. The range of transfer of platinum in placers usually does not exceed 8 km, while in oblique placers it is longer. Palladium and cuprous platinum varieties in the hypergenesis zone can be “ennobled”, losing Pd, Cu, Ni. The content of Cu and Ni, according to A.G. Betekhtin, in placer platinum can be reduced by more than 2 times in comparison with platinum from the primary source. In placers of many regions of the world, newly formed chemically pure platinum and paladic platinum have been described in the form of drip forms of a radial-radiant structure.

APPLICATION

Platinum compounds (mainly amminoplatinates) are used as cytostatics in the treatment of various forms of cancer. Cisplatin (cis-dichlorodiammineplatinum (II)) was the first to be introduced into clinical practice; however, more effective diammineplatinum carboxylate complexes - carboplatin and oxaliplatin - are currently used.

Platinum and its alloys are widely used in jewelry making.

The world's first platinum coins were issued and circulated in the Russian Empire from 1828 to 1845. The minting began with three-ruble coins. In 1829, “platinum duplons” (six-rubleviks) were established, and in 1830 - “quadruples” (twelve-rubleviks). The following denominations of coins were minted: in denominations of 3, 6 and 12 rubles. Three-rubleviks were minted 1,371,691 pieces, six-rubleviks - 14,847 pieces. and twelve rublers - 3474 pcs.

Platinum was used in the manufacture of insignia for outstanding services: the image of V. I. Lenin was made from platinum on the Soviet Order of Lenin; from it were made the Soviet Order "Victory", the Order of Suvorov 1st degree and the Order of Ushakov 1st degree.

• From the first quarter of the 19th century, it was used in Russia as an alloying additive for the production of high-strength steels.
• Platinum is used as a catalyst (most often in an alloy with rhodium, as well as in the form of platinum black - a fine powder of platinum obtained by reducing its compounds).
• Platinum is used to make vessels and stirrers used in the melting of optical glasses.
• For the manufacture of chemically resistant and strong heat-resistant laboratory glassware (crucibles, spoons, etc.).
• For the manufacture of permanent magnets with high coercive force and residual magnetization (alloy of three parts of platinum and one part of cobalt PlK-78).
• Special mirrors for laser technology.
• For the manufacture of durable and stable electrical contacts in the form of alloys with iridium, for example, contacts of electromagnetic relays (alloys PLI-10, PLI-20, PLI-30).
• Electroplated coatings.
• Distillation retorts for hydrofluoric acid production, perchloric acid production.
• Electrodes for the production of perchlorates, perborates, percarbonates, peroxoduseric acid (in fact, the use of platinum determines the entire world production of hydrogen peroxide: electrolysis of sulfuric acid - peroxodivuseric acid - hydrolysis - distillation of hydrogen peroxide).
• Insoluble anodes in electroplating.
• Heating elements for resistance furnaces.
• Manufacturing of resistance thermometers.
• Coatings for microwave technology elements (waveguides, attenuators, resonator elements).

Platinum - Pt

CLASSIFICATION

Strunz (8th edition)	1 / A.14-70
Nickel-Strunz (10th Edition)	1.AF.10
Dana (7th Edition)	1.2.1.1
Dana (8th Edition)	1.2.1.1
Hey's CIM Ref	1.82

PHYSICAL PROPERTIES

OPTICAL PROPERTIES

CRYSTALLOGRAPHIC PROPERTIES

Point group	m3m (4 / m 3 2 / m) - isometric hexaoctahedral
Space group	Fm3m
Syngonia	cubic
Cell parameters	a = 3.9231Å
Twinning	total by (111)

Among all the noble metals, platinum occupies a special place and its cost is higher in comparison with gold and silver. The fact is that the extraction of this substance is a rather laborious process, and it is also rare. The higher cost of Platinum is due at least to the fact that about 10 tons of rock have to be processed to produce one ounce. In turn, to create a similar amount of gold, it takes about 3 tons of ore.

Even before our era, people knew about the metal platinum, for example, the ancient Egyptians used it to make jewelry. It was widely used by the Inca Indians, but it was gradually forgotten. Recent history mining and processing of platinum dates back to the period of the development of America by the Spanish conquistadors.

However, at first, the metal was not given due attention, as evidenced by even its name - translated from Spanish the word it means "small silver". It was often considered to be immature gold at all and was thrown away. It's a pretty refractory metal., with a high density index, which made it much more difficult to process.

But after the discovery of one unique ability, the situation changed - platinum and gold are easily fused. Jewelers were the first to take advantage of this feature, starting to add it to gold: jewelry made of the new alloy had a lower cost. At the same time, the high density of the metal contributed to the increase in weight. finished product, but this was more than offset by the addition of silver, which did not affect the shade in any way.

For a long time, it was not possible to distinguish such jewelry from ordinary ones. When this did happen, they even banned the import of platinum into Europe for some time. Platinum was recognized as an independent chemical element only in the 18th century, when scientists were able to carefully study the properties of the metal.

The first platinum deposits in Russia were discovered near Yekaterinburg in 1819. Five years later, new deposits were found in the Nizhniy Tagil District, and they are so extensive that Russia in short time took a leading position in metal mining.

Physical and chemical properties

Opinion on what platinum is White gold, is still found among the common people. In fact, it is an independent chemical element with unique properties. First, about how platinum is designated - Platinum or Pt. In the periodic table of chemical elements, this is one of the heaviest metals. He conceded the palm only to osmium and iridium, which also belong to the substances of the platinum group.

Among the properties of the metal, the most unique are worth noting:

• When heated to temperatures below 200 degrees, it is not subject to oxidation and does not enter into chemical interaction with other substances.
• Indicators of hardness and density are higher in comparison with gold and even more so with silver.
• Differs in high ductility and lends itself well to forging.
• It has excellent electrical conductivity.
• Does not interact with acids, except aqua regia.
• It has a high melting point of 1768.3 degrees.

Pure metal is practically not found in nature, and if we talk about what platinum consists of, then most often these are alloys with rhodium, palladium, iron, iridium and some other substances.

The oxidation rate depends on the oxygen pressure and the rate of oxygen supply to the metal surface. Since it is most often mined in the form of alloys, the presence of other substances in them slows down this process.

The most common oxides are:

The specific resistance of platinum is relatively small, but in terms of electric current conductivity, it is inferior to aluminum, silver, and copper. At the same time, during heating, the resistivity index increases, and the specific conductivity decreases accordingly. Scientists explain this fact by the fact that as the temperature rises, the particles that make up the platinum begin to move chaotically and, as a result, the passage of current becomes difficult.

The industry actively uses the ability of platinum to accelerate various chemical reactions, which makes it an excellent catalyst.

Application area

In medicine, metal compounds, mainly amminoplastinates, are used in the treatment of various forms of cancer. The first such drug was cisplastin, but currently oxaliplatin and carboplatin are the most popular. The use of metal in technology is much wider. If we talk about where platinum is contained, the main directions can be noted:

Since about the middle of the 18th century, platinum has been performing a monetary function in Russia. Exactly the first platinum coins were produced in the Russian Empire, and it happened in 1828. Currently, some states continue to mint coins of various denominations, but they are most often used for investment. It should also be said about the jewelry industry, which annually consumes about 50 tons of metal. Platinum jewelry is most popular in Japan.

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The most valuable of metals

The history of the discovery of metal sends us back several thousand years. Opinions are divided as to when platinum was discovered. Some scholars argue that this metal was known and actively used by such ancient civilizations as the Incas, Aztecs and Maya tribes. However, these civilizations have existed for so long that there is no reliable data left about it.

The version of other researchers sounds more likely. Platinum was discovered by man in the 18th century, in South America. Then people did not know its enormous value and treated platinum with disdain. Due to its similarity to silver and the lack of the ability to melt it.

Today man is well aware of the value of platinum. According to the Central Bank of the Russian Federation, the price of platinum is 1,743.75 rubles / gram.

The chemical composition of platinum

In its pure form, like other precious metals, platinum is rare. Most often there are nuggets, in which the majority (80% -88%) is platinum, and the rest is iron. This variety is called polyxene. There are also varieties with a content of nickel (about 3% nickel), palladium (from 7% to 40% palladium), iridium, rhodium (up to 5% rhodium).

In the periodic table it is called Platina, it has the designation Pt. Group - 10, period - 6, atomic number - 78, atomic mass- 195.084 g / mol. Platinum does not interact with most elements. However, under the influence of high temperatures, the reaction can manifest itself.

Platinum reacts with:

• "Aqua regia" - dissolves in it in the usual temperature regime;
• sulfuric acid - dissolves in concentrate at elevated temperatures;
• liquid bromine - dissolves in the concentrate at elevated temperatures;

When exposed to high temperatures:

• alkalis;
• sodium peroxide;
• halogens;
• sulfur;
• carbon (forms a solid solution);
• selenium;
• silicon (forms a solid solution);
• oxygen (forms volatile oxides).

Metal is a good catalyst. As a catalyst, it is indispensable in industry.

Has a cubic face-centered crystal lattice

In the free state, the metal is a monatomic molecule

Physical properties

In nature, it is most often found in the form of gray-white nuggets ranging in size from small grains to stones weighing 8 kg.

Basic physical characteristics:

• ρ = 21.09-21.45 g / cm3;
• Melting point - 1768.3 ᵒС;
• Boiling point - 3825 ᵒС;
• Thermal conductivity - 71.6 W / m × K;
• Mohs scale hardness - 3.5.

Platinum without impurities is a diamagnetic. However, more often in nature, it occurs in the form of polyxene, which is magnetised. Possesses high electrical conductivity and ductility (malleability and ductility).

The metal is most actively used in the chemical industry. Due to its ductility and electrical conductivity, it is suitable for the manufacture of sulfuric acid, as well as laboratory glassware, which is exposed to high temperatures.

The metal is widely used in the electrical industry, if necessary, electroplating, as a coating for various elements of electrical devices.

Platinum as a catalyst is indispensable in the oil refining industry.

In addition, the value of the metal is great in the automotive, glass, monetary industries, in jewelry, medicine (especially in dentistry).

Platinum mining

Leadership in the extraction of precious metal belongs to Russia, South Africa, Canada, USA, Colombia. The annual production is 36 tons of metal.

The Americans were the first to mine platinum. Russia discovered platinum much later, in 1819 in the Urals. Subsequently, several more deposits of valuable metal were discovered. Already in 1828, production in Russia was 1.5 tons. Which significantly exceeded the results of South America. At the end of the 19th century, Russia became the undisputed leader and received 40 times more valuable metal than all other countries.

South Africa is the modern leader. Russia is in second place and produces about 25 tons per year. World reserves of platinum today amount to about 80 thousand tons and are divided between South Africa, Russia and America.

Artificial platinum

Platinum is considered a rare precious metal. Its extraction and subsequent is a rather complicated and laborious process. Nevertheless, it is widely used in almost all areas of industry and human life. Its price is quite high and no decrease is expected. The demand for metal is growing, and its amount in nature is only decreasing. In order to make the metal more affordable and somewhat reduce its cost, the World Investment Council decided to artificially synthesize this metal. The Russian scientific center "Synthestech" is also taking an active part in this issue. For the production of artificial platinum, the cold transmutation method is used.

Platinum is a rare and sought-after precious metal that has a number of unique properties. Translated from Spanish, the word “fee” means small silver, some say “silver” this metal received this name because of its grayish-white hue.

Platinum has a high density, making it one of the heaviest precious metals. A piece made of platinum weighs twice as much as a silver piece. A platinum cube with an edge length of 300 mm would have a weight equal to 0.5 tons.

Platinum is a fairly plastic material. From a small piece of platinum, weighing only 30g, you can get a very thin wire that could connect the German city of Cologne and the capital of Russia Moscow.

Platinum does not undergo oxidation and corrosion, having chemical resistance, it is practically insoluble in alkalis and acids. Tsarskaya vodka, prolonged exposure to sulfuric acid and liquid bromine can dissolve platinum.

Platinum has several other good qualities - hardness and refractoriness, which gives platinum products resistance to abrasion and resistance to high temperatures. The melting point of the "silver" is 18430 ° C, and the boiling point is 3890 ° C.

Platinum compounds in nature

There is little platinum in the earth's crust. Platinum is rarely found in its pure form. It is most often found in conjunction with rare metals such as iridium. The rest of the metals belonging to the platinum group (ruthenium, osmium and rhodium) can be found in small concentrations. Platinum is also found in the form of compounds with copper, iron, chromium and nickel, as well as silver.

Platinum in the ore is represented by small grains or inclusions. Especially large nuggets have not been found in nature.

Scope and history of platinum development

The first deposits of platinum were found in South America in the 18th century.

For a long time, platinum did not arouse interest among Europeans. Its price was low.

Later, having learned the unique properties of platinum, people began to use it more often. All this led to an increase in the price of the precious metal.

Platinum is found in small quantities in the earth's crust. Therefore, its price is high. So a platinum cube with a 300 mm edge length has a market value of $ 2.0 million.

Platinum in the jewelry industry

Among jewelers, platinum is rightfully considered the queen of precious metals.

Today, platinum jewelry is a symbol of confidence and solidity.

Platinum is used today and how jewelry, and as a reliable investment project.

The high strength of the metal increases the demand for its production. Wedding rings platinum is the most demanded piece of jewelry. They do not wear out. Wearing them for a long time rarely causes an allergic reaction.

The cost of a gram of platinum ranges from 3.5 to 4.5 thousand rubles.

Along with the jewelry field, platinum is indispensable in the production of high-precision electronic technology and equipment used in scientific research. Platinum is indispensable in instruments designed for accurate measurements.