Osmium

OSMIUM-I; m. Chemical element (Os), bluish solid metal white color(included as a component in the composition of superhard and wear-resistant alloys).

(lat. Osmium), Os, a chemical element of group VIII of the periodic system, refers to platinum metals. Name from Greek. osmē - smell, according to the sharp smelling oxide OsO 4 . Density 22.61 g / cm 3, t pl 3027°C. A catalyst for many reactions, a component of superhard and wear-resistant alloys with iridium.

OSMIY (lat. Osmium), Os (read "osmium"), a chemical element with atomic number 76, atomic mass 190,2.
There are seven stable isotopes in nature 184 Os (0.018%), 186 Os (1.59%), 187 Os (1.64%), 188 Os (13.3%), 189 Os (16.1%), 190 Os (26.4%) and 192 Os (41.1%). The configuration of the outer and pre-outer electron layers is 5s 2 p 6 5d 6 6s 2 . The oxidation states are +4, +6, +8 (the most typical), +1, +3, +5 (valencies I, III, IV, V, VI, VIII). Belongs to platinum metals. (cm. PLATINUM METALS) It is located in group VIII of the periodic system of elements, in the iron subgroup, in the 6th period. Atomic radius 0.135 nm, ionic radius of the ion Os 4+ - 0.077 (coordination number 6), Os 5+ - 0.072 (6), Os 6+ - 0.069 (6), Os 7+ - 0.067 (6), Os 8+ - 0.053 nm (4). Sequential ionization energies 8.5, 17 and 25 eV. Electronegativity according to Pauling (cm. PAULING Linus) 2,1.
Osmium is a heavy, silvery-white metal.
Discovery history
Discovered in 1804 by the English chemist S. Tennant (cm. TENNANT Smithson) in the black powder remaining after the dissolution of platinum (cm. PLATINUM) in royal vodka (cm. AQUA REGIA). Osmium is characterized by the formation of tetroxide OsO 4 with a pungent odor. Hence the name of the element, derived from the Greek "osme" - smell.
Being in nature
Osmium is a very rare element, content in earth's crust 5 10 -6% by weight. Occurs naturally in polymetallic ores containing also platinum (cm. PLATINUM) and palladium (cm. PALLADIUM (chemical element))(sulfide copper-nickel and copper-molybdenum ores). The main minerals are natural alloys of osmium with iridium (nevyanskite (cm. osmium iridium), sysertskit) and platinum. Occurs as compounds with sulfur (cm. SULFUR) and arsenic (cm. ARSENIC)(erlichmanite, osmium laurite, osarsite). As an isomorphic impurity, it is part of chalcopyrite (cm. chalcopyrite) , pyrrhotite (cm. PYRRHOTINE), pentlandite, (cm. PENTLANDIT) cubanite, magnetite (cm. MAGNETITE). Usually the content of osmium in ores does not exceed 1·10–3%.
Receipt
The process of isolation and separation of platinum metals, leading to the separation of these metals and the production of osmium, is described in the article iridium (cm. IRIDIUM). Another way to isolate osmium from enriched raw materials is to calcinate the platinum metal concentrate in air at temperatures of the order of 800-900°C. In this case, OsO 4 vapors are sublimated, which are then absorbed with a NaOH solution.
By evaporation of the solution, a salt is isolated - sodium perosmate, which is then reduced with hydrogen at 120 ° C to osmium:
Na 2 + 3H 2 \u003d 2NaOH + Os + 4H 2 O.
Osmium is obtained in the form of a sponge.
Physical and chemical properties
Osmium is a heavy silvery-white metal (density at 20 ° C 22.65 g / cm 3). Hexagonal grating, type Mg, a= 0.27353 nm, With= 0.43191 nm. Melting point 3027°C, boiling point 5027°C. At temperatures below 0.66 K, osmium passes into the superconducting state. Metallic osmium paramagnetic (cm. PARAMAGNETIC). In the series of standard potentials, it is to the right of hydrogen (cm. HYDROGEN), does not react with non-oxidizing acids and water.
The chemical activity of osmium depends on its state. Compact osmium begins to oxidize in air at temperatures above 400°C, while fine osmium powder slowly oxidizes to OsO 4 already at room temperature.
Compact osmium does not dissolve in hot hydrochloric acid and boiling aqua regia. (cm. AQUA REGIA), and finely crushed osmium is oxidized in nitric acid and boiling sulfuric acid to a higher oxide:
Os + 8HNO 3 \u003d OsO 4 + 4H 2 O + 8NO 2
When heated, osmium reacts with fluorine (cm. FLUORINE), chlorine (cm. CHLORINE), oxygen (cm. OXYGEN), gray (cm. SULFUR), other chalcogens (cm. CHALCOGENES) and nonmetals.
Os + 3F 2 = OsF 6 (at 250–300°C),
Os + Cl 2 = OsCl 4 (at 650–700°C).
When fused in the presence of oxidizing agents, osmium reacts with alkalis. In this case, osmates (VI) are formed - salts of unstable osmic acid H 2 OsO 4:
2Os + 4NaOH + 3O 2 = 2Na 2 OsO 4 + 2H 2 O
For osmium, the formation of oxides OsO 4 and OsO 2 is most characteristic. The oxides OsO and OsO 3 exist in the gas phase.
Osmium tetroxide OsO 4 exhibits acid properties and is a strong oxidizing agent.
OsO 4 + NaOH \u003d Na 2.
Osmium dioxide OsO 2 is obtained by careful dehydration in an atmosphere of nitrogen Os(OH) 4 . In this case, a black modification of OsO 2 is formed. It is more reactive than the brown modification OsO 2 obtained by electroreduction of an alkaline solution of OsO 4 or by the reaction of osmium with OsO 4:
Os + OsO 4 \u003d 2OsO 2.
Osmium (IV) hydroxide Os (OH) 4 (OsO 2 2H 2 O) is obtained by reducing osmium (VI) salts - osmates with ethyl alcohol.
For the oxidation states of osmium 0 and +2, the formation of organosmium compounds with an Os-C bond or carbonyls is most characteristic:
Os + 5CO = Os(CO) 5 .
3Os(CO) 5 \u003d Os 3 (CO) 12 + 3CO
Os 3 (CO) 12 + 6Na \u003d 3Na 2 Os (CO) 4.
Application
Osmium is a component of superhard and wear-resistant alloys with iridium (parts of very precise instruments, precision small contacts), with iridium and ruthenium (nibs for fountain pens), with tungsten and molybdenum (cathodes of thermionic diodes), a component of a composite material (electrical contacts). OsO 4 is used for staining biological preparations.
Physiological action
Osmium compounds, especially volatile ones, are highly toxic. OsO 4 tetroxide irritates mucous membranes, affects the respiratory system. MPC in the air is 0.002 mg/m 3 .

encyclopedic Dictionary. 2009 .

See what "osmium" is in other dictionaries:

osmium- Osmium, I... Russian orthographic dictionary

- (Greek, from osme smell, from ozo I smell). Metal, from the platinum group, bluish white, combustible, very hard and brittle, rare. Dictionary foreign words included in the Russian language. Chudinov A.N., 1910. OSMIY Greek, from osme, ... ... Dictionary of foreign words of the Russian language

- (symbol Os), white-blue TRANSITION ELEMENT, a metal discovered in 1803. Being the densest element, osmium occurs in compounds with platinum. It is obtained mainly as a by-product from nickel smelting. Like IRIDIUM, osmium ... ... Scientific and technical encyclopedic dictionary

Osmium is a chemical element with atomic number 76. In the periodic system of chemical elements of D. I. Mendeleev, it is denoted by the symbol Os (lat. Osmium). Under standard conditions, it is a bluish-silver brittle transition metal. Belongs to the group of platinum metals. It has a high density, comparable in this parameter only with iridium (the densities of Os and Ir are almost equal, taking into account the calculated error).

Story

Osmium was discovered in 1804 by the English chemist Smithson Tennant in the sediment left after dissolving platinum in aqua regia. Similar studies were carried out by the French chemists Collet-Descoti, Antoine Francois de Fourcroix and Vauquelin, who also came to the conclusion about the content of an unknown element in the insoluble residue of platinum ore. The hypothetical element was given the name pten (winged), but Tennant's experiments showed that it was a mixture of two elements - iridium and osmium.
Named from other Greek. ὀσμή (smell), according to the sharply smelling volatile oxide OsO 4 (reminiscent of ozone).

Receipt

Osmium is isolated from the enriched raw material of platinum metals by calcining this concentrate in air at temperatures of 800-900 °C. In this case, vapors of highly volatile osmium tetroxide OsO 4 are quantitatively sublimated, which are then absorbed with a NaOH solution.
By evaporating the solution, a salt is isolated - sodium perosmate, which is then reduced with hydrogen at 120 ° C to osmium:
Na 2 + 3H 2 \u003d 2NaOH + Os + 4H 2 O.

Osmium is obtained in the form of a sponge.

Properties

Physical
Osmium is a gray-bluish, hard but brittle metal with a very high specific gravity, retaining its luster even at high temperatures. Due to its hardness, brittleness, low vapor pressure (the lowest among all platinum metals), as well as a very high melting point, metallic osmium is difficult to machining. Osmium is considered the most dense of all chemical elements, slightly surpassing iridium in this parameter. The most reliable density values ​​for these metals can be calculated from the parameters of their crystal lattices: 22.562 ± 0.009 g/cm³ for iridium and 22.587 ± 0.009 g/cm³ for osmium. When comparing various isotopes of these metals, 192 Os turns out to be the densest. Extraordinarily high density osmium is explained by lanthanide contraction.

Chemical
Osmium powder, when heated, reacts with oxygen, halogens, sulfur vapor, selenium, tellurium, phosphorus, nitric and sulfuric acids. Compact osmium does not interact with either acids or alkalis, but forms water-soluble osmates with alkali melts. Slowly reacts with nitric acid and aqua regia, reacts with molten alkalis in the presence of oxidizing agents (potassium nitrate or chlorate), with molten sodium peroxide. In compounds, it exhibits oxidation states from -2 to +8, of which the most common are +2, +3, +4 and +8.
Osmium is one of the few metals that form polynuclear (or cluster) compounds. Osmium polynuclear carbonyl Os 3 (CO) 12 is used for modeling and research chemical reactions hydrocarbons on metal centers. The carbonyl groups in Os 3 (CO) 12 can be replaced by other ligands, including those containing cluster nuclei of other transition metals.

Most people believe that there is nothing more precious 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 analyze one of them today. This is osmium, the price for 1 gram in rubles of which will impress any person.

In 1803, the English chemist Smithson Tennant discovered Os by discovering it in a sediment that appeared after the scientist dissolved platinum in aqua regia. In parallel, experiments were carried out in France, where the chemists Vauquelin and Antoine De Fourcroix also identified an unknown element in the sediment left 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 letter 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. Subjected to critical temperatures, it always retains its natural color and luster.

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

Chemical properties

The substance in powder form, when heated, reacts well with oxygen, sulfur elements, selenium, phosphorus. Slowly enters into a relationship with aqua regia.

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

Where is it mined

Osmium iridium 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 common in combination with arsenic and sulfur. In ores, the amount of substance is negligible.

Osmium cost

The cost of one gram of this substance is 15-200 thousand dollars. The market price of the metal is much less. This high cost is due low level mining Os. 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 in the world. Only California is more expensive, the production of which 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, has the form of a black powder, consisting of small crystals. Although osmium is the densest substance on our planet, it is very fragile. By smell, the metal immediately resembles bleach and garlic. That is why he received such a name (stands for "smell").

The metal is indispensable in scientific, medical and research activities, as it is a chemical catalyst, and it is used in the manufacture of measuring instruments that provide 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 rather unusually. Several substances were diluted in aqua regia and it was found that a precipitate had formed that had a not very pleasant smell.

Os is not used to make jewelry, as it does not have malleability and ductility - the properties for which precious metals are so valued by jewelers.

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 for the manufacture of their products. It goes to them already as a secondary raw material, but it still costs a lot.

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

Where is used

The isotope of osmium is used to make containers for storing nuclear waste. Also, the substance is used in the space industry. And it also accelerates the synthesis of ammonia, organics. 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 recent times the industry is trying to abandon the use of metal, due to its high cost and difficult processing.

Metal is used only in the case where success is 100% guaranteed.

Osmium oxide is used for medical purposes, in biology. Many implants and pacemakers are not made without the help of the substance in question. The latter are made from platinum, which contains 10% osmium.

Fountain pens are often produced, in which the tips are 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 several times without any breakage of the substance.

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

Methods for obtaining a substance

Osmium is most commonly stored in powder form. In this form, the metal easily reacts, and heat treatment takes place without difficulty. Os does not melt and cannot be branded if the metal is pure.

With the help of electron (sometimes arc) beams, ingots are obtained from metal. Single crystals are created using zone melting. But this method of manufacturing is very expensive, and therefore the price of the created products is high. But there are unique ones who can create crystals from powder. This is a long and complex process that requires a lot of energy, but the results are still there.

Earlier it was said that osmium has bad smell. The substance tetroxide is widely used in medicine. He is jokingly called "beautiful and odorous." Tetraoxide crystals can be made at home, but care must be taken as the substance is toxic.

For example, to kill a mouse with tetroxide, it takes 40 times less of this substance than hydrocyanic acid (it is considered a recognized poison against rodents). Such a damaging effect is explained by the fact that, getting inside the body, the substance instantly comes to metallic look. This results in 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 organism of living beings

The element is very harmful and toxic to biological beings. When osmium is inhaled, the lungs fail (their edema occurs), and anemia develops in a living being.

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

It becomes hard to breathe, there are spasms in the bronchi and a metallic taste in the mouth. If a person is not taken away from the affected area in time, he is threatened with blindness, impaired kidney function, nervous system, organs of the gastrointestinal tract. Possible death.

The metal also affects the integrity of the skin. She turns black or green. Ulcers, blisters appear on it. The tissue begins to die.

You can get poisoned with osmium at work, in case of a slight excess of the amount of this substance in the air. On many modern productions osmium is present in the air, although, according to experts, its concentration in the air should not be at all.

Table 1 - osmium price (1 gr.) in comparison with others 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. Whereas osmium costs about 1800 rubles per gram.

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

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

Several tens of kilograms per year. Such is the production of osmium. It is included in the top of the most expensive metals in the world, and it is in second place after California.

How much is given for one gram, we will tell later. In the meantime, we note that the high cost of raw materials justifies its use only where the result is more important.

The result is osmium provides one that other metals are not capable of. Why? The answer is an enumeration of the element's properties.

Osmium properties

Osmium - metal, insoluble in and alkalis. Even their powerful representatives are powerless before the element.

Moreover, it remains unharmed in - mixtures and acids. , to the group of which osmium belongs, for example, amenable to aqua regia.

Chemical inertness allows the use osmium alloys and coatings from it in aggressive environments. Specific examples will be described in a separate chapter.

Raw materials for products are usually - powdered osmium. It is not difficult to get it, because the substance crumbles easily.

In the form of a powder, osmium, although slowly, but dissolves in nitrogen and sulfuric concentrates, reacts with vapors,, and.

You can get from the powder and osmium amalgam, that is, its solution in .

The interaction of osmium with other substances is accompanied by an unpleasant, pungent odor.

This is the "flavor" of the hero. The name was given to him by the discoverer - the British chemist William Wollaston. From the Greek "osmium" is translated as "smell".

The appearance of the element, on the contrary, is attractive. Metal is considered one of the most beautiful. Osmium crystals silver blue.

The metal is dark blue, casts. The powder of the element is deep purple.

However, with such an appearance, Osmium's "modeling career" did not work out. do not work with metal.

Due to the price, and, at the same time, fragility, the element cannot be machined.

The infusibility of the substance also interferes with it. Osmium is an element softening only at temperatures above 3000 degrees Celsius.

What is not to one's liking comes in handy in heavy industry. For the nuances there is a separate chapter.

Here, it is worth saying that in addition to refractoriness, attention is worthy osmium density. That's almost 23 grams per cubic centimeter.

This indicator makes the hero of the article the heaviest metal in the world. Pour the osmium powder into a plastic bottle.

Now, pour water into a metal bucket of liters, that way, 20. Raise. The bottle will be several times heavier.

The effect of metal compounds on the body is also difficult. osmium oxide, or other substances with it, affect internal organs cause loss of vision.

Poisoning by element vapors can be fatal. The norm of osmium in the atmosphere is 5 times less than that of hydrocyanic acid, only 0.002 milligrams per cubic meter.

Within this content, the metal is even able to benefit. So, British scientists proved that osmium blocks the development of cancer cells.

Osmium methods for the treatment of oncological diseases are already being developed. Where else, and how, the hero of the article can come in handy, we will tell further.

Application of osmium

Before the discovery of the anti-cancer properties of osmium, it was also used by physicians, but in implants. They are made from noble metals so that there are no allergic reactions and, in general, any reactions with the environment.

For each implant - its own. Osmium is needed in pacing, that is, it replaces the elements of the heart.

Implants are implanted into it, consisting of 10% osmium. The rest - .

It is not surprising that the cost of the equipment is comparable to the price tag for the work of the best surgeons in the best clinics in the world.

Of the platinum group, osmium is the least consumed metal. Due to the high cost and rarity, they are looking for replacements.

So, in the last century, the hero of the article was part of incandescent lamps, as the most refractory metal.

But found worthy alternative– . From the last incandescent they made several decades.

Has not outlived its usefulness osmium application, as a component of alloys for instruments and tools.

Products with the heaviest metal break records for wear resistance. It is made up of an element that competes with only, refractoriness, immunity to chemical reagents.

If you want to get a cutter for which there will be no demolition, or a scalpel with which you can operate on all living beings, order tools with osmium.

Buy osmium Industrialists are also striving for measuring technology. In it, metal is present on the axes and arrows.

For them, the absence of properties is important. Osmium meets the request. In the mechanisms, the hero of the article, by the way, also comes in handy.

The element is used, as a rule, in elite models. So, Rolexes cost millions of dollars for a reason.

The price tag consists not only of the prestige of the company, high-quality mechanism and case. Precious elements are also inside the watch. Osmium is a noble metal, and it is not for nothing that it is included in the group of platinoids.

Of the osmium alloys, duets with and are the most common. They are produced, for example, for technical tips with increased physical and chemical resistance.

Electrical contacts are made from an alloy with. Osmium sell It is also possible for the production of electrical contacts. In them, along with the heaviest metal, tungsten is also added.

Osmium tetroxide used in electron microscopy. Here is the most heavy metal serves as a fixator of biological objects. A rare element ensures the safety of the microstructures of their cells.

Tetroxide is the most used compound osmium. His a photo can be posted on the network with the signature "catalyst".

In this role, osmium is more effective. In particular, the synthesis, production of certain drugs and hydrogenation of organic matter cannot do without the hero of the article.

Now, the promised information about heavy industry. Osmium 187, and other isotopes of a substance are used in rocket science, aircraft, and also in military warheads.

Metal strengthens them, allows them to withstand extreme temperatures and loads.

187th osmium isotope- just one of. The metal has several types of nuclides. These are varieties of the atom. They differ in the number of neutrons in its nucleus.

In osmium, all isotopes are similar in melting point, appearance,. This complicates the separation of particles, their extraction.

As a result, even more jumps osmium cost. Let's figure out what industrialists have to go through in order to reveal powdered metal to the world.

Osmium mining

"Tamara and I go as a couple." Phrase from nursery rhyme can be applied to osmium. Only, he "walks in pairs" with.

The metal does not occur separately in nature. So, the industrialists are faced with the task of not only separating the isotopes of the hero of the article, but also separating him from the “comrade”.

Along with, osmium is often accompanied by iridium, palladium and other platinoids, led by the most fortunate.

In it, along with Tasmania, the USA,Australia and Colombia, the main reserves of the rare substance are concentrated. But, the largest deposits are in South Africa.

Therefore, it largely establishes osmium prices. What they are in the current year, we will tell in the final chapter.

Osmium price

Osmium price per gram exceeds $200,000. This data is from the top of the most expensive metals. However, it was compiled in the early 2000s.

The situation has changed. There is a tendency to increase production. Since osmium is extracted along the way, there has been a temporary increase in production to 200 kilograms per year and, as a result, the cost of the heaviest substance has decreased.

However, given the limited reserves of both platinum and osmium, in the long term, the price tag will still grow.

The exception will be a situation in which scientists find a worthy and more cost-effective replacement for the hero of the article.

It should be noted that the price of osmium varies depending on the type of isotope. The most practical, chemically resistant and is the 187th.

For him, they ask for the maximum. There are also 188th, 189th, 190th, 191st and 192nd nuclides.

Of these, only the 191st is not stable, that is, it can be used in the nuclear industry, therefore, it is also highly valued, but it almost falls short of the 187th.