Chemistry of osmium. Precious metal - osmium

Most people believe that there is nothing more expensive than gold, silver and platinum in the world. But in fact, there are several substances whose price per gram exceeds that of the three metals listed above. We will look at one of them today. This is osmium, the price for 1 gram in rubles will impress any person.

In 1803, the English chemist Smithson Tennant discovered Os, finding it in a precipitate that appeared after the scientist dissolved platinum in aqua regia. At the same time, experiments were carried out in France, where chemists Vauquelin and Antoine DeFourcroy also identified an unknown element in the sediment remaining from the dissolution of platinum ore. At first, the new element was called “pten” (translated from Greek as “winged”). But further research made it possible to determine that this is not one element, but a mixture of two - iridium and osmium.

The new substances were officially documented in Tenant's message to the Royal Club of London in June 1804.

Physical properties

The substance has a gray-bluish color. The metal is very brittle, but has a high specific gravity. Being exposed critical temperatures, it always retains its natural color and shine.

Since metal is hard, it has high temperature melting (3033 degrees Celsius), it is difficult to machine.

Chemical properties

Substance in powder form, when heated, reacts well with oxygen, sulfur elements, selenium, phosphorus. Slowly interacts with aqua regia.

The metal is one of several substances that form cluster compounds.

Where is it mined?

Iridium osmide is mined in Siberia and the Urals in Russia; in Alaska and California in the USA; Australia (and the island of Tasmania); South African state. The last country on the list boasts the largest metal deposits on the planet.

More often found in combination with arsenic and sulfur. The amount of substance in ores is insignificant.

Osmium cost

The cost of one gram of this substance is 15-200 thousand dollars. The market price of the metal is several times lower. This high cost is due to the low level of Os production. It is simply not used on a large scale due to its enormous density. If we make a comparison: a half-liter bottle with the substance in question will be heavier than 12 liters of water. Osmium is one of the three most expensive metals peace. Only Californian is more expensive, its production is less than a gram per year.

The metal in question is very difficult to mine, and the process takes more than 9 months. The substance is an isotope and has the appearance of a black powder consisting of small crystals. Although osmium is the densest substance on our planet, it is very fragile. The smell of the metal immediately resembles bleach and garlic. That is why it received such a name (stands for “smell”).

The metal is indispensable in scientific, medical and research activities, since it is a chemical catalyst, and it is used in the production of measuring instruments that produce data of the highest accuracy.

The only state that sells osmium is Kazakhstan.

Other facts

The metal melts at temperatures above 3000 degrees Celsius. The boiling point reaches almost 6000 degrees.

It was opened in a rather unusual way. Several substances were diluted in aqua regia and it was discovered that a precipitate had formed that had a not very pleasant odor.

Os are not used for making jewelry, since it does not have malleability and ductility - those properties for which jewelers value precious metals so much.

The substance is found in ore deposits. It can also be found in meteorites that have fallen to Earth. Some industries are in dire need of metal to make their products. It goes to them as secondary raw material, but it is still not cheap.

Metal is used only because of its incredible strength. Alloys to which osmium is added become incredibly wear-resistant. It only takes minimal doses of the substance to add to the alloy to make it very strong.

Where is it used?

Osmium isotope is used to make containers for storing nuclear waste. The substance is also used in the space industry. It also accelerates the synthesis of ammonia and organic matter. By the way, tungsten filaments contain the described metal.

Since the substance is famous for its strength, it is used in the manufacture of weapons. But in Lately industry is trying to abandon the use of metal due to its high cost and difficult processing.

Metal is used only in cases where success is 100% guaranteed.

Osmium oxide is used for medical purposes and in biology. Many implants and pacemakers are made with the help of the substance in question. The latter are made from platinum, which contains 10% osmium.

Fountain pens are often produced with tips made of the metal in question. Such products are more durable than samples with gold ends.

Interesting! If you make an alloy of osmium with aluminum, it will be incredibly ductile. It can be pulled out several times without any tearing of the substance.

When the pressure is above 770 GPa, electrons located in the inner orbitals will interact in osmium, but the structure of the metal will not change at all.

Methods for obtaining the substance

Osmium is most often stored in powder form. In this form, the metal easily reacts and can be heat treated without any difficulties. Os does not melt and cannot be branded if the metal is in its pure form.

Using electron (sometimes arc) rays, metal is produced into ingots. Single crystals are created using zone melting. But this manufacturing method is very expensive, and therefore the price of the created products is high. But there are unique people who know how to create crystals from powder. This is a long and complex process that requires a lot of energy, but there are still results.

It was previously said that osmium has bad smell. The substance tetroxide is widely used in medicine. It is jokingly called “beautiful and fragrant.” Tetroxide crystals can be made at home, but be careful as the substance is toxic.

For example, to kill a mouse with tetroxide, it takes 40 times less of this substance than hydrocyanic acid (considered a recognized poison against rodents). This damaging effect is explained by the fact that, upon entering the body, the substance instantly becomes metallic. This causes damage to the respiratory tract and vision. But despite this, OsO4 is widely used as a dye in the chemical industry.

How does Os affect the body of living beings?

The element is very harmful and toxic to biological beings. When osmium is inhaled, the lungs fail (swelling occurs), and the living creature develops anemia.

When even a small amount of the substance is in the air, an individual experiences tearing, pain in the eyes, and conjunctivitis may develop.

It becomes difficult to breathe, spasms in the bronchi and a metallic taste in the mouth appear. If a person is not removed from the affected area in time, he or she faces blindness, impaired kidney function, nervous system, gastrointestinal organs. Possible death.

Metal also affects the integrity of the skin. It turns black or green. Ulcers and blisters appear on it. The tissue begins to die.

You can be poisoned by osmium at work if the amount of this substance in the air is slightly exceeded. On many modern production Osmium is present in the air, although, according to experts, its concentration in the air should not be there at all.

Table 1 - osmium price (1 g) in comparison with other precious metals (market).

Conclusion

Although osmium is considered one of the most expensive metals on the planet, its market price is not so high. For example, 1 gram of gold can be bought for 2000-2500 rubles. While osmium costs about 1800 rubles per gram.

The cost of osmium varies everywhere, but only Kazakhstan sells it at the cheapest non-market price. The fact is that not only osmium, but also its isotope (osmium 187) is traded on the world market. It is the second one that has an incredible cost, due to the difficulty of processing, separation from other isotopes and limited use.

Now it’s clear how much osmium 187 and regular Os cost at the market price. Ordinary Os is a mixture of isotopes.

The dumbbells and barbells that bodybuilders use to pump up their muscles are made of steel. Projectiles made from lead - or better yet - would lose significant volume. But it’s even better to use osmium to produce weights: A kilogram of osmium is a small ball that can easily fit in a clenched fist. A half-liter bottle of powdered osmium (this is the form in which the noble metal leaves the walls of the enrichment plant) weighs noticeably more than a bucket of water.

But you can’t find anyone brave enough to cast weights from osmium: it’s too refractory. And the cost of the metal is such that an athletic club would have to work for three hundred years to buy one osmium dumbbell...

Not enough osmium!

In nature, osmium occurs mainly in the form of a compound with iridium, which is part of either native platinum or platinum-palladium ore. The minerals considered raw materials for osmium mining contain on average one thousandth of a percent of the heavy “relative” platinum. During the entire period of research, not a single osmium nugget was mined, even of the smallest size.

The small quantity and difficulty of obtaining osmium determines the height of its price. Half a century ago, osmium was valued at seven to eight times more expensive than gold. Speculation recent years led to the emergence of completely insane offers: a gram of osmium was sold for both 10 thousand and 200 thousand dollars. It was sold, but it was not sold: osmium is not actively used, although it is used in some places.

Discovery of osmium

Wollaston, who experimented with platinum ores, was close to the discovery of osmium. Encouraged by his successes, the Frenchmen Antoine de Fourcroy and Louis-Nicolas Vauquelin began their own research and correctly assumed the existence of a new element, which evaporated in the form of black smoke during experiments.

Fourcroix and Vauquelin gave the substance the name "ptene" - which means "volatile", and calmed down, awaiting recognition. However, the English chemist Smithson Tennant divided the “pten” into two related metals, one of which was called iridium for the variety of colors of its compounds, and the second, because of its irritating stench, was called osmium.

These things happen important events in the year 1803, generous with discoveries.

Properties of osmium

Until recently, the melting and boiling points were considered to be conditionally equal to 3000° and 5000°C: there were no means for full-scale verification of calculations. Only a few years ago it was possible to clarify the physical parameters of the metal. Apparently it turns out that it is better to cook osmium alloys on the surface of the Sun...

Interesting appearance osmia Solidifying from the melt, osmium forms hard and brittle crystals, the silvery sheen of which is shaded by a grayish-blue (and even blue) tint. The external advantages of osmium could attract jewelers, but the high chemical activity of the metal and the toxicity of its compounds exclude the possibility of using this platinum in jewelry.

Applications of osmium

Osmium catalysts are used in the hydrogenation of organic compounds, in the production of drugs, and in the synthesis of ammonia. True, the high cost of the metal forces industrialists to look for affordable substitutes, and today osmium is becoming less and less common in the chemical industry.

Axles, supports and support sockets are made from solid and non-magnetic osmium. measuring instruments high precision. And although ruby ​​supports are harder and cheaper than osmium ones, the durability of the metal is sometimes preferable for instrument making.

Osmium is dangerous and requires caution

It is almost impossible to avoid osmium oxidation, if the metal comes into contact with atmospheric oxygen. Therefore, no use of osmium in

Ordinal element with atom number 76 in chemical system DI. Mendeleev's name is osmium. In solid form, the metal has a shiny silver-white color with bluish tints. Counts heavy metal, the density of osmium is 22.6 g/cm3. But at the same time, it is fragile and can be used to make powder. It was in this state that the metal was discovered by the English chemist S. Tennant. Transition metal, part of the platinum group. In a small state it is susceptible to oxidation at room temperature.

Properties of osmium

A precious metal the densest (22.61 g/cm3) and refractory. Physical properties osmia are as follows:

1. Melts at a temperature of 3047 °C, boils at 5025 °C, cannot be processed mechanically, cannot be dissolved in acid and aqua regia.

2. It has an unpleasant smell, reminiscent of a mixture of garlic and bleach, which is added to give the platinum alloy hardness and elasticity.

3. Atomic mass osmium is 190.23 g/mol.

4. Isotope 187 is the result of the decay of the rhenium isotope. Due to its chemical inertness, osmium alloy is used in aggressive acidic environments.

5. The metal is easily crushed, in powder form purple dissolves slowly in acids, reacts with compounds such as sulfur, selenium, tellurium and phosphorus.

6. In a crumbly state, it reacts with mercury to form an osmium amalgam.

7. When interacting with other substances, it emits a bad odor.

8. Externally, the crystals look beautiful. When exposed to high temperatures, it melts, forming hard and brittle crystals. The color of the metal is gray-blue with a silvery sheen.

Its external characteristics could be appreciated by jewelers, but due to its toxicity and chemical interaction with other elements it is not used for the production of jewelry.

The earth's crust consists of 0.5% of this metal, mainly in the center of the earth - the core. A piece of metal, like an egg, weighs one kilogram. If powder from this substance is poured into a 0.5 liter container, its weight will be 16 kg.

The chemical properties of the noble metal are as follows:

• in the solid state it oxidizes at temperatures above 400 C, in powder it already reacts at room temperature (OsO4);
• when heated, interacts with sulfur, chlorine, fluorine, sulfur and other chemical elements;
• it does not dissolve in boiling hydrochloric acid, but in a finely crushed form combines with molecules of nitric acid and is oxidized: Os + 8HNO3 = OsO4 + 4H2O + 8NO2;
• black osmium dioxide OsO2 is released during dehydration in a nitrogen atmosphere;
• Hydroxyl osmium (IV)Os(OH)4 (OsO2 2H2O) is obtained by reduction of metal(VI) salts.

There are six isotopes in nature, one of the 186 isotopes decays into alpha group compounds. Osmium exists the longest - 194 with a half-life of two years. Osmium differs little from its fellow platinum group metals (ruthenium, palladium, osmium, iridium, platinum), but is superior to other metals due to its density and ability to boil at very high temperatures.

It is found in nature in native form as a solid solution with iridium (minerals nevyanskite and sysertskite).

Application

The addition of osmium to various alloys makes them more stable, durable, and not subject to mechanization and corrosion.

1. Electrochemical industry: used in tungsten, nickel and cobalt compounds. All products are wear-resistant.
2. Introduction of platinum group metal into hardware increases their strength. Very little of the substance is needed to create sharp blades, medical products and technical products.
3. Fountain pens with nibs do not wear out for a long time.
4. In cardiology: the metal has found its intended use in implants (pacemakers) and in the replacement of pulmonary valves.
5. Combined with tungsten, it is used to produce filaments for electric lamps.
6. It does not have magnetic attraction, which is why it has found its application in the manufacture of watch parts.
7. Catalysts made from it are used in production medicines, synthesize ammonia. The higher oxide of this metal is used in the production of artificial medicines and in the laboratory - it is used to stain tissue under a microscope.
8. Hard metal is used in the manufacture of supports and axes for high-precision measuring instruments. Due to its hardness, the metal is used in instrument making.
9. Osmium 187 and other isotopes are used in heavy industry: rocketry, airliners, military equipment. Thanks to its wear resistance, it helps to withstand extreme conditions.

History of discovery

Osmium is a noble metal. But this contradicts its status: translated from Greek, “osme” means smell, that is, chemically active. And nobility implies the inertness of this substance.

Osmium was discovered in 1803. The English chemist S. Tennant, in collaboration with William H. Wollaston, experimented with dissolving osmium in aqua regia, but nothing came of it. Similar tests were carried out by French chemists Collet-Descoti, Antoine de Fourcroix and Vauquelin. They discovered an insoluble precipitate of platinum ore in this element. Chemical element assigned the name Pten, from the Greek word meaning flying. With this experiment they proved the presence of two chemical substances- osmium and iridium.

Where is it in nature and how is it obtained?

In nature, noble metal does not exist in nuggets. It is mined from the following rocks: sysertskite, nevyanskite, osmiiride and sarsite. It is part of copper, molybdenum and nickel ores. According to some data, it contains compounds of arsenic and sulfur.

The share of matter on the planet is 0.000005% of total mass everyone rocks. In nature, osmium combines with iridium, the percentage of which ranges from 10 to 50. There are reserves of this metal in Africa, Tasmania, Australia, the United States, Canada, Colombia, and Russia. The richest country in terms of osmium content is South Africa (deposit of the Bushveld complex). The noble metal can be found in alloys of native platinum, but more often in alloys of osmium and iridium.

The crumbly state is the most acceptable form of existence. In this form he enters better chemical reactions and is subjected to heat treatment. Platinum group metal can be obtained in the following ways:

• use of electron beam;
• arc heating;
• use of crucibleless zone melting.

Crystals obtained using the latter method are very expensive. Someone managed to grow crystals from powder, but the method is difficult and time-consuming.

Price

The metal is quite scarce in nature, and extracting osmium is a costly project, so this determines its price on the market. In the 60–70s of the 20th century, the precious metal was several times more expensive than gold. They sold it cheap, but it was valued at a high price; because of this, the offers on the market were staggering: a gram of metal was estimated at 10 thousand, and for 200 thousand dollars. Gold is not as valuable as its platinum group counterpart.

Why is osmium dangerous?

The chemical compound osmium damages human organs. Inhalation of vapors is fatal. When animals were intoxicated, anemia was observed and pulmonary function was impaired.

Do you know that tetraosmium oxide OsO4 is a rather aggressive compound, and if it is poisoned, green or black bubbles appear on the skin. It is not easy for a person, since treatment will take a long time.

To those who work for hazardous industries, you should treat yourself with caution. For this purpose, enterprises issue protective suits and respirators.