Ruthenium - chemical element: description, history and composition. Ruthenium. Properties of ruthenium. Applications of ruthenium What country was ruthenium named after?
Ruthenia means "Russia" in Latin. Like Russia, ruthenium is beautiful, mysterious and extremely inconvenient for humans. Firstly, obtaining pure ruthenium is a problem, has not yet been resolved. Secondly, ruthenium is so fragile that it is not possible to use it in its pure form. Third, ruthenium, found in the form of various chemical compounds, is often dangerous. Including explosive ones!
Why not Russia?
History of metal
Karl-Ernst Klaus, a Baltic German, was born and raised in Estonia. As a child, he was torn between the desire to become a botanist and the idea of making a living as an apothecary. However, fate told him to forget about nonsense, realize himself as a Russian chemist and go to serve at Kazan University.Karl Karlovich resisted as best he could. He married a German woman, did not give up botany (one of the cabbage genera is named after him), and treated chemistry not only with disdain, but... not seriously. He touched acids with his hands, tasted solutions, smelled poisonous gases in order to remember their smell, and often expressed thoughts unbecoming of a respectable scientist. In general, he showed all the traits of the Russian character - and not in vain!
Most of the statements made by Professor K.K. Klaus's ideas, too bold for their time, turned out to be correct. Implementing one of them, in 1844, Klaus received six grams of a metal previously unknown to science and subsequently named ruthenium.
The luminaries of the world community noted the closeness of the new metal, partly to iron, partly to osmium. A strong opinion arose - and has not disappeared since then - that Of all the so-called “noble” metals, ruthenium is the most base...
Properties of ruthenium
For one hundred and fifty years now, ruthenium has been at the complete disposal of researchers, but there is still no comprehensive understanding of its capabilities. Experimenters were faced with a paradoxical phenomenon: the physical properties of this platinum substance change depending on the method of obtaining the metal.The presence of a difference in properties, scientists understand, only indicates that the samples are contaminated. Awareness of the problem is partly puzzling, because there is no effective way to purify ruthenium from impurities; and partly it is encouraging, since the theoretical characteristics of the substance are very enviable.
One way or another, today it is not possible to rid ruthenium of the inherent fragility of its castings. Attempts at mechanical processing (forging, pressing, cutting) end in the destruction of the ruthenium workpiece.
Meanwhile, production workers are very interested in “conquering” metal: the gas absorption capabilities of ruthenium are unsurpassed. If palladium is able to absorb hydrogen 940 times its volume, then for ruthenium this figure is almost twice as high! Moreover, the absorption capacity of ruthenium concerns not only hydrogen, but also nitrogen, and - to a lesser extent - other non-metals.
Ruthenium tetroxide RuO4 (as well as finely divided rhodium) is so chemically active that it is even explosive. True, both rhodium and ruthenium explosives are quite expensive...
Price and prevalence
According to geologists, ruthenium in earth's crust no more than five thousand tons. Such a small quantity, scattered nature and difficulty of extraction determine the initially high cost of the metal.However, limited demand makes adjustments to the price list of precious metals. Ruthenium is the most inexpensive of. Its market value at the beginning of 2016 is only 2.7 times higher than the price of ruthenium, which is almost 30 times more expensive - despite the fact that the annual production of ruthenium rarely exceeds 20 tons, and 2,500 tons of gold enter the world market per year.
No fairness in pricing! Just as it doesn’t exist in the country of Ruthenia...
Where does ruthenium go?
Unlike most precious metals, ruthenium is not used in the jewelry industry, absolutely. The point here is not only the lack of expressiveness of its natural appearance and the inconvenience of its physical properties. The chemical activity of ruthenium compounds is so great Doctors are confident that the introduction of metal into human use will inevitably lead to an increase in morbidity.The lion's share of mined ruthenium goes to the electronics industry. About a third of the production volume is purchased by enterprises of the electrochemical cycle. The remaining third is consumed by conventional chemical production. Very few ruthenium compounds are required by medicine for the manufacture of research and therapeutic drugs.
Water purification devices on spacecraft operate on ruthenium catalysts - they are the most effective. In non-ferrous metallurgy, ruthenium is a valuable alloying additive. In concentrations of tenths and hundredths of a percent, the noble metal significantly increases the strength properties of products. Turbine blades of jet engines, high-temperature parts of rockets, and fuel equipment for aircraft contain ruthenium.
Some technologies for producing graphene are based on the use of ruthenium's ability to absorb non-metals. The ruthenium substrate turns out to be a reliable basis for growing modified carbon.
A powdered mixture of ruthenium dioxide and ruthenium tetroxide allows forensic scientists to identify faint fingerprints. No other compounds “bite” into fat molecules with such force!
The use of ruthenium paint as...a solar battery seems very promising. In the future, a person will be able to utilize solar energy using a converter worn in the form of a can of paint and two wires - and such a system promises to cost mere pennies.
Problematic ruthenium
Nuclear scientists, and along with them environmentalists, faced the ruthenium problem. For them, radioactive ruthenium, which appears in reactors during the decay of uranium and plutonium, is a serious and intractable problem.Up to a third of the slag mass in the reactor is dangerous radioruthenium. Extremely sticky metal is extremely difficult to remove. But when preserving nuclear waste, ruthenium is the first to find a way out of storage! Migration of active ruthenium occurs in all possible ways.
It is not always possible to put a reliable barrier in the way of an element that is too “movable,” or to decontaminate the metal. Leguminous plants, a favorite food of humans and animals, concentrate soil ruthenium in their roots.
The topic of ruthenium has been discussed in the media for several days now. I won’t retell it - I think you know.
So what is it, did it happen, and if so, why is it dangerous?
What is ruthenium and where is it used?
Ruthenium is a platinum metal. There are now seven stable and 27 radioactive isotopes of ruthenium known.
Ruthenium is used in alloys to increase wear resistance - for example, in titanium the proportion of ruthenium is 0.1%, and in the production of electrical contacts, ruthenium is alloyed with platinum. Ruthenium alloys are extremely resistant to high temperatures, which is why they are used in aerospace engineering as structural materials. Ruthenium compounds are used in jewelry, in electronics - in particular, in thin-film resistors (this accounts for 50% of all applications of ruthenium), as well as in solar panels. In addition, this metal is an important catalyst for chemical reactions: for example, it is used to purify water at orbital stations.
How was ruthenium discovered?
In fact, this element was discovered three times. But officially the discovery belongs to Kazan University professor Karl Klaus. In 1844, a scientist examined the remains that were obtained after extracting platinum and platinum metals from ore. Klaus fused these remains with saltpeter. He exposed the part of the resulting alloy that did not dissolve in water to aqua regia, a mixture of nitric and hydrochloric acid that dissolves metals, and distilled what was left to dryness. From the resulting substance, the chemist isolated iron hydroxide in the form of a precipitate and dissolved it in hydrochloric acid. The dark purple-red color of the solution led him to believe that an unknown element was present. Klaus managed to isolate this element - however, not in its pure form, but in combination with sulfur.
New element was named after Russia - ruthenium (from the Latin Ruthenia). Initially, the idea for the name belonged to another scientist, the German chemist Gottfried Ozanne - he gave this name to one of the three platinum metals, which he also obtained when analyzing Ural platinum ore in 1928. However, Ozanne's discovery was not confirmed during the test. However, Klaus believed that it was ruthenium that Ozanne had obtained, and mentioned this. There is also a version that the element was discovered three decades earlier by Polish professor Andrzej Sniadecki - he proposed calling the metal vestia, in honor of the asteroid Vesta, discovered in 1807.
What is known about ruthenium-106?
This is a radioactive isotope with a half-life of just over a year - of all the unstable isotopes of ruthenium, this is the longest-lived. It is absent in nature: it appears during the fission of uranium and plutonium into nuclear reactors- in fact, it is a by-product of the disposal of spent nuclear fuel (SNF). At the end of irradiation of the fuel in the reactor, the activity of 106Ru reaches 2.01 Bq per ton of SNF - this is a fairly large figure.
The main problem with ruthenium-106 is that during nuclear fuel reprocessing it forms stable compounds that interfere with the production of new products. Chemists must remove ruthenium from components at every stage of the process to turn spent nuclear fuel into new fuel.
Ruthenium-106 is used in radiation therapy for malignant eye tumors. It can also be used in radioisotope thermoelectric generators, which are used, in particular, in power supply to spacecraft remote from the Sun. However, plutonium-238 is used in practice for these purposes, but ruthenium isotopes are not used.
Is ruthenium-106 dangerous to health?
Ruthenium-106, like any other source of ionizing radiation, has an effect on the body. It is included in group B - the second most radiotoxic. Group A includes particularly dangerous radionuclides: polonium-210, radium-226, plutonium-238 and other alpha emitters. It is easy to protect yourself from a stream of alpha particles with a sheet of paper, since they have low penetrating ability - but if they do enter the body, they cause radiation sickness.
Ruthenium-106 is a beta emitter - simply put, it emits a stream of electrons. Beta decay first produces rhodium-106, which immediately decays to stable palladium-106. In both stages, electrons are emitted, as well as a small component of gamma radiation. If a beta particle enters the body, it causes 20 times less harm than an alpha particle - but its penetrating power is higher.
Why all the fuss about ruthenium?
On October 12, Roshydromet published a bulletin on the radiation situation in Russia for September 2017, which indicated cases of increased beta activity in the air and during precipitation. In particular, there was talk of increased activity of ruthenium-106 - for example, in the Dema microdistrict in Ufa on September 26-27, “ruthenium rain” occurred. Even earlier, in September, European monitoring stations recorded an excess of ruthenium-106 in the air. German Federal Office for Radiation Protection and Federal Ministry for Protection environment, environmental protection and reactor safety suggested that the source of ruthenium is in the Southern Urals.
So is this really dangerous?
The devil is not as scary as he is painted. The activity of ruthenium-106 is several orders of magnitude below the maximum permissible norm and does not cause harm to health - this was initially emphasized by Roshydromet in its statement.
“It is very difficult to determine ruthenium in the atmosphere, especially in such low concentrations,” says a member of the Department of Radiochemistry at St. Petersburg State University.
For example, for Argayash the bulletin contains data of 7.72 x 10 -5 Bq/m3, while the permissible activity value of ruthenium-106 according to modern standards is 4.4 Bq/m3. The appearance in the report of data on the excess of ruthenium-106 in samples relative to the previous period by “hundreds” of times, Roshydromet explained by the fact that this radionuclide was completely absent in previous samples. As Boris Martsinkevich, editor-in-chief of the Geoenergetics.ru portal, explains, the fact that radiological monitoring stations were able to detect such low concentrations of 106Ru can be considered “testing that convincingly proved that the stations operate at a good technical level.” The International Atomic Energy Agency (IAEA) has reviewed the data provided and denied accusations against Russia.
In addition, there are many natural alpha, beta and gamma emitters.
“If you go to the embankment in St. Petersburg, the background radiation there will be higher than in our laboratory,” says a member of the Department of Radiochemistry at St. Petersburg State University. “Because granite naturally has a high background radiation.”
Why did the activity of ruthenium-106 suddenly increase?
It is not known exactly. As Rosatom stated, there were no large releases of radioactive substances at Russian enterprises. The Mayak production association, in turn, categorically denies involvement in possible air pollution with the ruthenium-106 isotope. Major contamination of the atmosphere with ruthenium can occur when the seal of the fuel element shell in the reactor is broken, as well as when sources of ionizing radiation based on the isotope are destroyed. PA Mayak claims that the separation of the isotope from spent nuclear fuel, as well as the production of radiation sources from it, have not been carried out at the enterprise for many years. Moreover, with the first option, there is usually a release of other, “fragmentation” isotopes, which would certainly affect the indicators of these elements.
They say that ruthenium came from outer space - is this true?
Interfax published a version that the release of ruthenium-106 could have occurred during the destruction of the satellite. However, Alexander Zheleznyakov, an academician at the Tsiolkovsky Russian Academy of Cosmonautics, says that ruthenium-106 is not used in satellite power generators - and if such a device were taken out of orbit, its trajectory would be carefully monitored. Therefore, this version is on the verge of fantasy.
Where then could he come from?
The assumption of the head of the Department of Radiochemistry of the Faculty of Chemistry of Lomonosov Moscow State University, Corresponding Member of the Russian Academy of Sciences Stepan Kalmykov, seems plausible. He believes that a high-purity solution of radionuclide could have entered the atmosphere from a medical facility or enterprise where radiopharmaceuticals are worked or produced. This could have happened at a stage in the technical process where ruthenium is converted into an aerosol - due to its volatility it could spread into the atmosphere. Although other experts say that it does not look like a leak of ruthenium intended for medical purposes (it is used in radiation therapy): the cloud is too large. But an accident involving nuclear fuel or its waste is practically excluded, the expert says.
And the vice-governor of the Chelyabinsk region Oleg Klimov reported that “on September 25, even before reports of ruthenium in Europe, concentrations of ruthenium were recorded at control posts in the Southern Urals. Their size is 20 thousand times less than the permissible annual dose. The check showed that this is pure ruthenium, which came to us from another place,” noted Oleg Klimov. “The situation is artificially tense and has no basis.”
Maybe frightened Europeans should look for a source in another country? But it turns out that in the Old World, enterprises that have anything to do with working with radioactive substances are strictly classified. We know everything, and Russian meteorologists became victims of this transparency, who stated that yes, the content of ruthenium isotopes at two collection points exceeded the background of the previous month by hundreds of times. When it comes to radioactive substances, all this looks scary for amateurs. And a specialist, looking at the numbers, understands that both in Russia and in Europe the concentration of ruthenium-106 was thousands of times lower than any dangerous level. And in order not to scare people in the future, we decided to henceforth include comparisons with these same maximum concentrations in the reporting tables.
It is unlikely that the case of orphan ruthenium will be solved. Radiation is just a backdrop for the hype here. After all, in February, a cloud of the iodine isotope, much more dangerous than ruthenium, walked over Europe, but has anyone heard about it?
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Sergeeva Ekaterina Yurievna
State Autonomous Educational Institution "Chistopol Polytechnic College"
Head Ionycheva A.L.
ANNOTATION
In this work, I was interested in the history of the discovery, properties and possible areas of application of the chemical element Ruthenium, which was discovered by Karl Karlovich Klaus in the chemical laboratory of Kazan University and can rightfully be called the Kazan chemical element. 2011 was declared the Year of Chemistry by UNESCO, students of Kazan and the Republic of Tatarstan should remember this clearly extraordinary event in the more than 1000-year history of the city of Kazan And the only person in Russia, K.K. Klaus, who discovered a natural chemical element, especially since he is rightfully considered one of the founders of the Kazan chemical school.
This topic seemed interesting and relevant to us also because
Ruthenium is one of the representatives of the platinum metals, but was the most recently discovered. The discovery of Ruthenium presented great difficulties.
In order to discover a new element of the platinum group - ruthenium - in the time of Klaus, one had to have extreme observation, insight, hard work, perseverance and subtle experimental art. Klaus, one of the first brilliant representatives of chemical science at the then young Kazan University, possessed all these qualities to a high degree.
While studying the problem, we used materials from the Internet resource: the World of Chemistry website, Wiktionary, Popular Library of Chemical Elements, Nauka Publishing House, 2011.
During the week of natural sciences, we held (among other events) a scientific and practical conference: “Great chemists and their discoveries,” at which we presented research papers and a number of presentations that became a good help in the work of teachers and the interest of students in studying chemistry and other natural disciplines.
Kazan chemical element (Ruthenium)
“To discover a new element of the platinum group, ruthenium, in the time of Klaus, one had to have extreme observation, insight, hard work, perseverance and subtle experimental art. Klaus, one of the first brilliant representatives of chemical science at the then young Kazan University, possessed all these qualities to a high degree.”
Academician A.E. Arbuzov
History of the discovery of ruthenium
Ruthenium was the first chemical element discovered by the Russian chemist Karl Karlovich Klaus. Ruthenium is a representative of the platinum metals and was the last to be discovered.
The research was carried out by A. Snyadetsky, a Pole by nationality, and the Russian scientist K.K. Klaus. E.F. provided great assistance to the scientist. Kankrin, who at that time held the post of Minister of Finance
K.K. Klaus
It was he who provided Klaus with the remains of raw platinum, from which the scientist isolated platinum, as well as other metals: rhodium, palladium, iridium and osmium. In addition to these metals, he also isolated a mixture of others, which, according to Klaus, should contain a new, still unknown substance. The chemist repeated the experiments of G.V. Ozanne, and then, having developed his own experimental plan, obtained a new chemical element, ruthenium. And again he sent a letter to I. Bercellius, but he, as the first time, did not agree with Klaus’s arguments. But the Russian chemist did not heed Bercellius’s arguments and proved that he had discovered a new chemical element of the platinum group. And in 1845, Bercellius recognized the discovery of ruthenium.
A chemical element is named after Russia (the Latin name for Russia is Ruthenia)
At the request of the Ministry of Finance, Kazan University professor Karl Karlovich Klaus in 1841 began searching for a way to process the remains of platinum ores accumulated at the St. Petersburg Mint in order to more fully extract platinum. A year earlier, through the efforts of Rector Lobachevsky, a separate two-story building with a huge basement, equipped with the most modern equipment, was erected for the chemical laboratory.
Klaus established the composition of platinum ore residues and developed methods for separating and obtaining pure platinum metals. Klaus had to overcome exceptional experimental difficulties, given the level of knowledge at that time. In addition, the work was hazardous to health, since extremely toxic substances were formed during the processing of ores.
Among the isolated components, Klaus discovered a previously unknown metal. He studied the properties of both the metal itself and its compounds, determined its atomic weight with special care, and developed a method for its isolation and purification. In 1844, Klaus published his results, naming the new chemical element ruthenium, after Russia. The world scientific community initially accepted this discovery with doubt, since many elements were “discovered” by mistake.
It was not until 1846, when Klaus published a new paper on further study of ruthenium, that his discovery was universally accepted. Soon the Kazan professor was awarded the Demidov Prize by the Russian Academy of Sciences for research in the field of platinum metals. Its value of 10,000 rubles was then much greater than the current Nobel Prize.
Chemical laboratory of Kazan University, where Klaus worked in 1842. A hundred years later, the future Kurchatov Institute began its work in this room.
Obtaining ruthenium
The separation of platinum metals and obtaining them in their pure form (refining) is very difficult task, which requires a lot of labor, time, expensive reagents, as well as high skill. Currently, the main source of platinum metals is sulfide copper-nickel ores. As a result of their complex processing, the so-called “rough” metals are smelted - contaminated nickel and copper. During their electrolytic refining, noble metals accumulate in the form of anode sludge, which is sent for refining.
A significant source of ruthenium for its extraction is its separation from fission fragments of nuclear materials (plutonium, uranium, thorium), where its content reaches 250 grams per ton of “burnt” nuclear fuel.
Physical properties of ruthenium.
In terms of refractoriness (melt 2250 °C), ruthenium is inferior only to several elements - rhenium, osmium, tungsten.
The most valuable properties of Ruthenium are refractoriness, hardness, chemical resistance, and the ability to accelerate certain chemical reactions. The most typical compounds are those with valencies 3+, 4+ and 8+. Tends to form complex compounds. It is used as a catalyst, in alloys with platinum metals, as a material for sharp tips, for contacts, electrodes and in jewelry.
Chemical properties of ruthenium.
Ruthenium and osmium are brittle and very hard. When exposed to oxygen and strong oxidizing agents, they form the oxides RuO4 and OsO4. These are fusible yellow crystals. The vapors of both compounds have a strong, unpleasant odor and are very poisonous. Both compounds easily give up oxygen, being reduced to RuO2 and OsO2 or to metals. With alkalis, RuO4 gives salts (ruthenates). Ruthenium research poses three challenges for chemists today:
Task No. 1: How to get rid of ruthenium?
Ruthenium has many valuable and interesting properties. In many mechanical, electrical and chemical characteristics it can compete with many metals and even with platinum and gold. However, unlike these metals, ruthenium is very fragile, and therefore it has not yet been possible to make any products from it. Task No. 1 has been assigned to nuclear technology scientists.
Radioactive isotopes of ruthenium do not exist in nature, but they are formed as a result of the fission of uranium and plutonium nuclei in reactors of nuclear power plants, submarines, ships, and during explosions of atomic bombs. From a theoretical point of view, this fact is certainly interesting. It even has a special “zest”: the alchemists’ dream has come true - a base metal has turned into a noble one. Indeed, these days, plutonium production plants throw out tens of kilograms of the noble metal ruthenium. But the practical harm caused by this process to nuclear technology would not be worth it even if it were possible to put all the ruthenium produced in nuclear reactors to good use.
Why is ruthenium so harmful?
One of the main advantages of nuclear fuel is its reproducibility. As is known, when uranium blocks are “burned” in nuclear reactors, a new nuclear fuel is formed - plutonium. At the same time, “ash” is also formed - fragments of the fission of uranium nuclei, including ruthenium isotopes. Ash, of course, has to be removed.
Ruthenium begins to gradually migrate into the ground, creating the danger of radioactive contamination at large distances from the reservoir. The same thing happens when fragments are buried in mines at great depths. Radioactive ruthenium, which has (in the form of water-soluble nitroso compounds) extreme mobility, or, more correctly, migration ability, can travel very far with groundwater.
Physicists, chemists, technologists, and especially radiochemists in many countries pay a lot of attention to the fight against radioactive ruthenium. At the I and II International Conferences on the Peaceful Uses of Atomic Energy in Geneva, several reports were devoted to this problem. However, there is still no reason to consider the fight against ruthenium completed successfully, and, apparently, chemists will have to work a lot more in order for this problem to be transferred to the category of finally solved.
Task No. 2: further study of the chemistry of ruthenium and its compounds.
The extraordinary relevance of task No. 1 forces researchers to penetrate ever deeper into the chemistry of ruthenium and its compounds.
Ruthenium is a rare and very trace element. It is the only mineral known to form under natural conditions. This is laurite RuS 2 – a very hard, heavy, black substance that is extremely rare in nature. In some other natural compounds, ruthenium is just an isomorphic impurity, the amount of which, as a rule, does not exceed tenths of a percent. Small impurities of ruthenium compounds were discovered in copper-nickel ores of the Canadian Sedbury deposit, and then in other mines.
One of the most remarkable chemical properties of ruthenium is its many valence states. The ease of transition of ruthenium from one valence state to another and the abundance of these states lead to the extreme complexity and originality of ruthenium chemistry, which is still replete with many blank spots.
Soviet scientist Sergei Mikhailovich Starostin devoted his entire life to studying the chemistry of ruthenium and its compounds. It was he who established that the enormous difficulties that arise when separating ruthenium from plutonium and uranium are associated with the formation and properties of ruthenium nitroso complexes.
Some scientists suggest that it will be possible to isolate inorganic polymers based on ruthenium nitroso complexes.
Several decades ago, ruthenium complexes provided important service to the theory of chemistry, becoming an excellent model with which Werner created his famous coordination theory. Perhaps polymer compounds of ruthenium will serve as a model for creating the theory of inorganic polymers.
Challenge #3: Use of Ruthenium
Where is ruthenium used and what are the prospects for its use?
Ruthenium, like platinum and palladium, has catalytic properties, but often differs from them in greater selectivity and selectivity. Heterogeneous catalysis uses the metal ruthenium and its alloys. The most effective catalysts are obtained by depositing ruthenium on various supports with highly developed surfaces. In many cases it is used together with platinum in order to increase its catalytic activity. An alloy of rhodium, ruthenium and platinum accelerates the oxidation of ammonia in the production of nitric acid. Ruthenium is used for the synthesis of hydrocyanic acid from ammonia and methane, to obtain saturated hydrocarbons from hydrogen and carbon monoxide. A method for the polymerization of ethylene on a ruthenium catalyst has been patented abroad.
Ruthenium catalysts have become important for the reaction of producing glycerol and other polyhydric alcohols from cellulose by hydrogenation.
Organometallic compounds of ruthenium are used in homogeneous catalysis for various hydrogenation reactions, and in terms of selectivity and catalytic activity they are not inferior to recognized rhodium-based catalysts.
The main advantage of the ruthenium catalyst is its high selectivity. It is this that allows chemists to use ruthenium to synthesize a wide variety of organic and inorganic products. Ruthenium catalyst is beginning to seriously compete with platinum, iridium and rhodium.
Element No. 44 is somewhat less capable in metallurgy, but it is also used in this industry. Small additions of ruthenium usually increase the corrosion resistance, strength and hardness of the alloy. Most often it is introduced into metals from which contacts for electrical engineering and radio equipment are made. An alloy of ruthenium and platinum has found application in the fuel cells of some American artificial Earth satellites. Alloys of ruthenium with lanthanum, cerium, scandium, and yttrium have superconductivity. Thermocouples made from an alloy of iridium and ruthenium can measure the highest temperatures.
Much can also be expected from the use of ruthenium coatings applied as a thin layer (film) on various materials and products. Such a film significantly changes the properties and quality of products, increases their chemical and mechanical resistance, makes them corrosion-resistant, dramatically improves electrical properties, etc. Thin coatings of precious metals, including ruthenium, in last years are becoming increasingly important in various fields of electronics, radio and electrical engineering, the chemical industry, as well as in jewelry.
An interesting property of ruthenium metal - sorbing and passing hydrogen - can be successfully used to extract hydrogen from a mixture of gases and obtain ultra-pure hydrogen.
Many ruthenium compounds have beneficial properties. Some of them are used as additives in glass and enamels as permanent dyes; ruthenium chlorides, for example, increase the luminescence of luminol, ruthenium polyamines have fluorescent properties, Na2 2H2O salt is a piezoelectric, RuO4 is a strong oxidizing agent. Many ruthenium compounds have biological activity.
"Eternal" feather
Fountain pen nibs constantly rub against the paper and therefore wear off. To make the pen truly “eternal”, the tip is soldered. Some alloys for soldering “eternal” feathers include ruthenium. In addition to it, these alloys contain tungsten, cobalt, and boron.
Ruthenium is also used in the manufacture of alloys for compass needle supports. These alloys must be hard, strong and resilient. Among natural minerals, the very rare osmic iridium has such properties. Artificial materials for compass needles, along with osmium and iridium, and sometimes other metals, include element No. 44 - ruthenium.
There is contact!
In electrical engineering, copper has long been used for contacts. It is an ideal material for transmitting strong currents. So what if after a certain time the contacts become coated with copper oxide? You can wipe them with sandpaper and they will shine again, like new. It's a different matter in low-current technology. Here, any oxide film on the contact can disrupt the operation of the entire system. Therefore, contacts for low currents are made of palladium or a silver-palladium alloy. But these materials do not have sufficient mechanical strength. The addition of small amounts of ruthenium (1...5%) to the alloys gives the contacts hardness and strength. The same applies to sliding contacts, which must resist abrasion well.
Ruthenium red.
This is the name of an inorganic dye, which is a complex ammonium chloride of ruthenium. Ruthenium red is used in studies in anatomy and histology (the science of living tissues). A solution of this dye, when diluted 1:5000, colors pectin substances and some fabrics in pink and red tones. Thanks to this, the researcher is able to distinguish these substances from others and better analyze the section examined under the microscope.
Application of Ruthenium for growing graphene.
Researchers from Brookhaven National Laboratory (USA) have shown that during the epitaxial growth of graphene, macroscopic graphene regions are formed on the Ru(0001) surface. In this case, growth occurs layer by layer, and although the first layer is strongly connected to the substrate, the second practically does not interact with it and retains all the unique properties of graphene.
The synthesis is based on the fact that the solubility of carbon in ruthenium is strongly dependent on temperature. At 1150 °C, ruthenium is saturated with carbon, and when the temperature drops to 825 °C, carbon comes to the surface, resulting in the formation of graphene islands larger than 100 microns in size. The islands grow and unite, after which the growth of the second layer begins.
The topic of ruthenium has been discussed in the media for several days now. I won’t retell it - I think you know.
So what is it, did it happen, and if so, why is it dangerous?
What is ruthenium and where is it used?
Ruthenium is a platinum metal. There are now seven stable and 27 radioactive isotopes of ruthenium known.
Ruthenium is used in alloys to increase wear resistance - for example, in titanium the proportion of ruthenium is 0.1%, and in the production of electrical contacts, ruthenium is alloyed with platinum. Ruthenium alloys are extremely resistant to high temperatures, which is why they are used in aerospace engineering as structural materials. Ruthenium compounds are used in jewelry, in electronics - in particular, in thin-film resistors (this accounts for 50% of all applications of ruthenium), as well as in solar panels. In addition, this metal is an important catalyst for chemical reactions: for example, it is used to purify water at orbital stations.
How was ruthenium discovered?
In fact, this element was discovered three times. But officially the discovery belongs to Kazan University professor Karl Klaus. In 1844, a scientist examined the remains that were obtained after extracting platinum and platinum metals from ore. Klaus fused these remains with saltpeter. He exposed the part of the resulting alloy that did not dissolve in water to aqua regia, a mixture of nitric and hydrochloric acid that dissolves metals, and distilled what was left to dryness. From the resulting substance, the chemist isolated iron hydroxide in the form of a precipitate and dissolved it in hydrochloric acid. The dark purple-red color of the solution led him to believe that an unknown element was present. Klaus managed to isolate this element - however, not in its pure form, but in combination with sulfur.
The new element was named after Russia - ruthenium (from the Latin Ruthenia). Initially, the idea for the name belonged to another scientist, the German chemist Gottfried Ozanne - he gave this name to one of the three platinum metals, which he also obtained when analyzing Ural platinum ore in 1928. However, Ozanne's discovery was not confirmed during the test. However, Klaus believed that it was ruthenium that Ozanne had obtained, and mentioned this. There is also a version that the element was discovered three decades earlier by the Polish professor Andrzej Sniadecki - he proposed calling the metal vestia, in honor of the asteroid Vesta, discovered in 1807.
What is known about ruthenium-106?
It is a radioactive isotope with a half-life of just over a year—of all the unstable isotopes of ruthenium, it is the longest-lived. It is absent in nature: it appears during the fission of uranium and plutonium in nuclear reactors - in fact, it is a by-product of the disposal of spent nuclear fuel (SNF). At the end of fuel irradiation in the reactor, the activity of 106Ru reaches 2.01 Bq per ton of SNF - this is quite big number.
The main problem with ruthenium-106 is that during nuclear fuel reprocessing it forms stable compounds that interfere with the production of new products. Chemists must remove ruthenium from components at every stage of the process to turn spent nuclear fuel into new fuel.
Ruthenium-106 is used in radiation therapy for malignant eye tumors. It can also be used in radioisotope thermoelectric generators, which are used, in particular, in power supply to spacecraft remote from the Sun. However, plutonium-238 is used in practice for these purposes, but ruthenium isotopes are not used.
Is ruthenium-106 dangerous to health?
Ruthenium-106, like any other source of ionizing radiation, has an effect on the body. It is included in group B - the second most radiotoxic. Group A includes particularly dangerous radionuclides: polonium-210, radium-226, plutonium-238 and other alpha emitters. It is easy to protect yourself from a stream of alpha particles with a sheet of paper, since they have low penetrating ability - but if they do enter the body, they cause radiation sickness.
Ruthenium-106 is a beta emitter - simply put, it emits a stream of electrons. Beta decay first produces rhodium-106, which immediately decays to stable palladium-106. In both stages, electrons are emitted, as well as a small component of gamma radiation. If a beta particle enters the body, it causes 20 times less harm than an alpha particle - but its penetrating power is higher.
Why all the fuss about ruthenium?
On October 12, Roshydromet published a bulletin on the radiation situation in Russia for September 2017, which indicated cases of increased beta activity in the air and during precipitation. In particular, there was talk of increased activity of ruthenium-106 - for example, in the Dema microdistrict in Ufa on September 26-27, “ruthenium rain” occurred. Even earlier, in September, European monitoring stations recorded an excess of ruthenium-106 in the air. The German Federal Office for Radiation Protection and the Federal Ministry for the Environment, Nature Conservation and Reactor Safety have suggested that the source of ruthenium is in the Southern Urals.
So is this really dangerous?
The devil is not as scary as he is painted. The activity of ruthenium-106 is several orders of magnitude below the maximum permissible norm and does not cause harm to health - this was initially emphasized by Roshydromet in its statement.
“It is very difficult to determine ruthenium in the atmosphere, especially in such low concentrations,” says a member of the Department of Radiochemistry at St. Petersburg State University.
For example, for Argayash the bulletin contains data of 7.72 x 10 -5 Bq/m3, while the permissible activity value of ruthenium-106 according to modern standards is 4.4 Bq/m3. The appearance in the report of data on the excess of ruthenium-106 in samples relative to the previous period by “hundreds” of times, Roshydromet explained by the fact that this radionuclide was completely absent in previous samples. As Boris Martsinkevich, editor-in-chief of the Geoenergetics.ru portal, explains, the fact that radiological monitoring stations were able to detect such low concentrations of 106Ru can be considered “testing that convincingly proved that the stations operate at a good technical level.” The International Atomic Energy Agency (IAEA) has reviewed the data provided and denied accusations against Russia.
In addition, there are many natural alpha, beta and gamma emitters.
“If you go to the embankment in St. Petersburg, the background radiation there will be higher than in our laboratory,” says a member of the Department of Radiochemistry at St. Petersburg State University. “Because granite naturally has a high background radiation.”
Why did the activity of ruthenium-106 suddenly increase?
It is not known exactly. As Rosatom stated, there were no large releases of radioactive substances at Russian enterprises. The Mayak production association, in turn, categorically denies involvement in possible air pollution with the ruthenium-106 isotope. Major contamination of the atmosphere with ruthenium can occur when the seal of the fuel element shell in the reactor is broken, as well as when sources of ionizing radiation based on the isotope are destroyed. PA Mayak claims that the separation of the isotope from spent nuclear fuel, as well as the production of radiation sources from it, have not been carried out at the enterprise for many years. Moreover, with the first option, there is usually a release of other, “fragmentation” isotopes, which would certainly affect the indicators of these elements.
They say that ruthenium came from space - is this true?
Interfax published a version that the release of ruthenium-106 could have occurred during the destruction of the satellite. However, Alexander Zheleznyakov, an academician at the Tsiolkovsky Russian Academy of Cosmonautics, says that ruthenium-106 is not used in satellite power generators - and if such a device were taken out of orbit, its trajectory would be carefully monitored. Therefore, this version is on the verge of fantasy.
Where then could he come from?
The assumption of the head of the Department of Radiochemistry of the Faculty of Chemistry of Lomonosov Moscow State University, Corresponding Member of the Russian Academy of Sciences Stepan Kalmykov, seems plausible. He believes that a high-purity solution of radionuclide could have entered the atmosphere from a medical facility or enterprise where radiopharmaceuticals are worked or produced. This could have happened at the stage of the technical process where ruthenium turns into an aerosol - due to its volatility it could spread into the atmosphere. Although other experts say that it does not look like a leak of ruthenium intended for medical purposes (it is used in radiation therapy): the cloud is too large. But an accident involving nuclear fuel or its waste is practically excluded, the expert says.
And the vice-governor of the Chelyabinsk region Oleg Klimov reported that “on September 25, even before reports of ruthenium in Europe, concentrations of ruthenium were recorded at control posts in the Southern Urals. Their size is 20 thousand times less than the permissible annual dose. The check showed that this is pure ruthenium, which came to us from another place,” noted Oleg Klimov. “The situation is artificially tense and has no basis.”
Maybe frightened Europeans should look for a source in another country? But it turns out that in the Old World, enterprises that have anything to do with working with radioactive substances are strictly classified. We know everything, and Russian meteorologists became victims of this transparency, who stated that yes, the content of ruthenium isotopes at two collection points exceeded the background of the previous month by hundreds of times. When it comes to radioactive substances, all this looks scary for amateurs. And a specialist, looking at the numbers, understands that both in Russia and in Europe the concentration of ruthenium-106 was thousands of times lower than any dangerous level. And in order not to scare people in the future, we decided to henceforth include comparisons with these same maximum concentrations in the reporting tables.
It is unlikely that the case of orphan ruthenium will be solved. Radiation is just a backdrop for the hype here. After all, in February, a cloud of the iodine isotope, much more dangerous than ruthenium, walked over Europe, but has anyone heard about it?
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First, a few facts characterizing the special position of ruthenium among all chemical elements.
Ruthenium is one of the analogues of platinum. It is the lightest and, so to speak, the most “base” of the platinum metals.
Ruthenium is the most “multivalent” element: it can exist in at least nine valence states.
Ruthenium was the first element that made it possible to bind atmospheric nitrogen into a chemical compound (ruthenium complex), just as some bacteria do. Back in 1962, one of the authors of this article managed to obtain a complex compound of ruthenium with molecular nitrogen. The composition of this complex is [(NO)(NH 3) 4 RuN 2 , Ru(NH 3) 4 (NO)]Cl 6 . In 1965, Canadian scientist Albert Allen obtained a simpler compound (also complex) Cl 2.
Ruthenium is formed during the operation of nuclear reactors and during the explosion of atomic bombs. This is one of the most unpleasant fragmentation elements.
Ruthenium is an element discovered in our country in 1844 and named after our country. Ruthenia - Latin for Russia. The author of the discovery was Kazan University professor Karl Karlovich Klaus.
Ruthenium poses at least three problems for chemists today. They will be discussed in this article.
Problem #1: How to get rid of ruthenium
Ruthenium has many valuable and interesting properties. In many mechanical, electrical and chemical characteristics it can compete with many metals and even with platinum and gold. However, unlike these metals, ruthenium is very fragile, and therefore it has not yet been possible to make any products from it. Apparently, the fragility and intractability of ruthenium to mechanical processing is explained by the insufficient purity of the samples being tested. The physical properties of this metal very much depend on the method of production, and no one has yet succeeded in isolating ruthenium of high purity. Attempts to obtain pure ruthenium by sintering in briquettes, zone melting and other methods did not lead to positive results. For this reason, technically important characteristics such as tensile strength and elongation at break have not yet been precisely established. Only recently has the melting point of ruthenium been accurately determined - 2250°C, and its boiling point lies somewhere around 4900°C. Ruthenium metal very actively sorbs hydrogen. Typically, palladium is considered the standard of a hydrogen sorbent, a cubic centimeter of which absorbs 940 cm 3 of hydrogen. The absorption capacity of ruthenium is higher. It sorbs 1500 volumes of hydrogen.
Another important property of ruthenium: at a temperature of 0.47°K it becomes a superconductor.
Compact metal ruthenium does not dissolve in alkalis, acids and even in boiling aqua regia, but is partially soluble in nitric acid with the addition of strong oxidizing agents - perchlorates or bromates. Ruthenium can be dissolved in an alkaline medium with hypochlorites or in an acidic medium by electrochemical method.
When heated in air, ruthenium begins to partially oxidize. The maximum oxidation rate is observed at 800°C. Up to a temperature of 1000°C, ruthenium is always oxidized only into RuO 2 dioxide, but if it is heated to 1200°C and above, it begins to transform into volatile RuO 4 tetroxide, exhibiting a higher valence of 8+.
RuO 4 is a very interesting compound. Under normal conditions, these are golden-yellow needle-shaped crystals, which already melt at 25°C, turning into a brown-orange liquid with a specific odor, similar to the smell of ozone. Ruthenium tetroxide explodes immediately upon contact with the slightest trace of most organic substances. At the same time, it is highly soluble in chloroform and carbon tetrachloride. RuO 4 is poisonous: with prolonged inhalation of its vapors, a person begins to feel dizzy, and there are attacks of vomiting and suffocation. Some chemists who worked with ruthenium tetroxide developed eczema.
The ability of ruthenium to form tetroxide played a significant role in the chemistry of this element. By converting RuO 4 into the volatile form, it is possible to separate ruthenium from other noble and base metals and, after its reduction, obtain the purest ruthenium. Ruthenium impurities are removed from rhodium, iridium and platinum using the same method.
But it was not metallurgy that made the problem of combating ruthenium so urgent. Problem No. 1 is posed to nuclear technology scientists.
Radioactive isotopes of ruthenium do not exist in nature, but they are formed as a result of the fission of uranium and plutonium nuclei in reactors of nuclear power plants, submarines, ships, and during explosions of atomic bombs. Most radioactive isotopes of ruthenium are short-lived, but two - ruthenium-103 and ruthenium-106 - have fairly long half-lives (39.8 days and 1.01 years) and accumulate in reactors. It is significant that during the decay of plutonium, ruthenium isotopes account for up to 30% of the total mass of all fission fragments. From a theoretical point of view, this fact is certainly interesting. It even has a special “zest”: the alchemists’ dream has come true - a base metal has turned into a noble one. Indeed, these days, plutonium production plants throw out tens of kilograms of the noble metal ruthenium. But the practical harm caused by this process to nuclear technology would not be worth it even if it were possible to put all the ruthenium produced in nuclear reactors to good use.
Why is ruthenium so harmful?
One of the main advantages of nuclear fuel is its reproducibility. As is known, when uranium blocks are “burned” in nuclear reactors, a new nuclear fuel is formed - plutonium. At the same time, “ash” is also formed - fragments of the fission of uranium nuclei, including ruthenium isotopes. Ash, of course, has to be removed. Not only do the nuclei of fragmentation elements capture neutrons and break the chain reaction, they also create radiation levels that significantly exceed permissible levels. It is relatively easy to separate the bulk of fragments from uranium and plutonium, which is done at special plants, but radioactive ruthenium causes a lot of trouble.
Plutonium, unspent uranium and fragments are separated in special facilities. The first stage of separation is the dissolution of uranium blocks in nitric acid. This is where the troubles with ruthenium begin. When dissolved, part of it turns into complex nitroso compounds, which are based on a trivalent group (RuNO) 3+. This group forms complex compounds of various compositions in nitric acid. They interact with each other or with other ions in solution, hydrolyze, or even combine into inorganic polymer molecules. The complexes are completely different, but it is very difficult to separate and identify them. The endless variety of properties of ruthenium nitroso compounds poses many difficult questions to chemists and technologists.
There are several methods for separating fragments from plutonium and uranium. One of them is ion exchange. A solution containing various ions passes through a system of ion exchangers. The meaning of this operation is that uranium and plutonium are retained by ion exchangers in the apparatus, while other elements pass freely through the entire system. However, ruthenium is only partially removed. Some of it remains on the ion exchanger along with the uranium.
In another method - precipitation - uranium is precipitated using special reagents, and the fragments remain in solution. But along with uranium, part of the ruthenium also precipitates.
When purified by extraction, uranium is extracted from an aqueous solution with organic solvents, for example esters of organophosphorus acids. The fragments remain in the aqueous phase, but not all of them - ruthenium partially passes into the organic phase along with uranium.
They tried to avoid the difficulties of purifying nuclear fuel from ruthenium by using dry methods that eliminated the dissolution of uranium blocks. Instead of nitric acid, they were treated with fluorine. It was assumed that the uranium would then transform into volatile hexafluoride and be separated from the non-volatile fluorides of fragmentation elements. But ruthenium remained true to itself here too. It turned out that it also forms volatile fluorides.
Difficulties with ruthenium haunt technologists at the next stages of working with fissile materials. When collecting fragments from waste solutions, most of the foreign elements can be transferred to sediment, and ruthenium again partially remains in solution. Biological treatment does not guarantee its removal when waste solutions are poured into special drainless reservoirs.
Ruthenium begins to gradually migrate into the ground, creating the danger of radioactive contamination at large distances from the reservoir. The same thing happens when fragments are buried in mines at great depths. Radioactive ruthenium, which has (in the form of water-soluble nitroso compounds) extreme mobility, or, more correctly, migration ability, can travel very far with groundwater.
The problem of cleaning is decontamination of equipment, clothing, etc. – from radioruthenium also has its own specifics. Depending on the chemical state in which ruthenium was, it can either be easily washed and removed, or it can be deactivated with great difficulty.
Physicists, chemists, technologists, and especially radiochemists in many countries pay a lot of attention to the fight against radioactive ruthenium. At the I and II International Conferences on the Peaceful Uses of Atomic Energy in Geneva, several reports were devoted to this problem. However, there is still no reason to consider the fight against ruthenium completed successfully, and, apparently, chemists will have to work a lot more in order for this problem to be transferred to the category of finally solved.
Problem No. 2: further study of the chemistry of ruthenium and its compounds
The extraordinary relevance of problem No. 1 forces researchers to penetrate ever deeper into the chemistry of ruthenium and its compounds. The discovery of radioruthenium in fission products of nuclear fuel served as a powerful impetus for numerous works on the chemistry of ruthenium and made it the object of close attention. They didn't do it that much before.
In 1844, professor of chemistry at Kazan University Karl Karlovich Klaus obtained 6 g of an unknown silvery-white metal from raw platinum, determined its atomic mass, basic physicochemical constants and individual properties of some of its compounds. Ruthenium became the 57th element known to chemists.
Many well-known chemists were involved in the development of certain issues in the chemistry of ruthenium over the years: Berzelius, Saint-Clair Deville, Debray, Remy, Werner, etc. It was found that in some chemical properties ruthenium is close to iron, and in others - to rhodium and especially to osmium, that it can exhibit several valences, that stable ruthenium oxide has the formula RuO 2.
Ruthenium is a rare and very trace element. It is the only mineral known to form under natural conditions. This is laurite RuS 2 - a very hard, heavy, black substance that is extremely rare in nature. In some other natural compounds, ruthenium is just an isomorphic impurity, the amount of which, as a rule, does not exceed tenths of a percent. Small impurities of ruthenium compounds were discovered in copper-nickel ores of the Canadian Sedbury deposit, and then in other mines.
Academician A.E. Fersman found traces of ruthenium in igneous acid rocks and many minerals. However, the question of the dispersion of ruthenium during the destruction of rocks and its further fate has not yet been fully studied. Its solution is complicated by the fact that ruthenium, on the one hand, produces sparingly soluble oxides that accumulate in rock residues, and on the other hand, mineral and surface waters dissolve part of the ruthenium, it goes into solution and dissipates. Strong adsorbents and biochemical agents can reconcentrate ruthenium from solutions. Thus, increased concentrations of ruthenium were found in the mineral pyrolusite MnO 2. Some plant species also have the ability to accumulate this element; in particular, it is concentrated in the roots of legumes.
One of the most remarkable chemical properties of ruthenium is its many valence states. The ease of transition of ruthenium from one valence state to another and the abundance of these states lead to the extreme complexity and originality of ruthenium chemistry, which is still replete with many blank spots.
Look how numerous the ruthenium compounds are presented below, how many complex and still little studied compounds are among them (the symbol M denotes monovalent metals).
Very few scientists have systematically studied the chemistry of ruthenium. Some of them published one or two papers and moved on to other elements, while others, unable to cope with the avalanche of constantly emerging new questions, left their work on ruthenium not even completed. It is for this reason that we consider ourselves obliged to mention in this article the name of the very early deceased Soviet scientist Sergei Mikhailovich Starostin, who devoted his entire life to the study of the chemistry of ruthenium and its compounds. It was he who established that the enormous difficulties that arise when separating ruthenium from plutonium and uranium are associated with the formation and properties of ruthenium nitroso complexes.
But let's return to the numerous valences of ruthenium. Having familiarized yourself with its compounds, you have come across nine valencies - from zero to eight. It would seem much more! But that is not all. Ruthenium is also capable of forming compounds with multiple bonds, the creation of which involves not one, but several pairs of electrons. In addition to covalent bonds formed due to the pairing of a free electron of ruthenium with an electron of any other atom, this element can also form more complex ones - dative and donor-acceptor bonds. For example, it has been established that in the compound K 4 (Ru 2 ОCl 10) · H 2 O the Ru ↔ O ↔ Ru bond (2 · 1.8 Å) is multiple. It is shorter and stronger than single Ru – O.
Bonds of all three types participate in the formation of ruthenium nitroso compounds. The presence of a nitroso group in these compounds leads to the formation by ruthenium of a very stable 18-electron configuration of the inert gas krypton, which explains the unusually high chemical and thermal stability of ruthenium nitroso complexes - compounds of greatest interest for nuclear technology. The valence of ruthenium in its nitroso complexes should be considered equal to four; it is the most stable valence form of ruthenium.
Among other things, ruthenium can form long-chain polymer molecules. It is characterized by the formation of chains similar to silicone ones: – Ru – O – Ru – O – Ru – O –. In addition, the existence of polymer compounds constructed as follows has been proven:
Some scientists suggest that it will be possible to isolate inorganic polymers based on ruthenium nitroso complexes.
Several decades ago, ruthenium complexes provided important service to the theory of chemistry, becoming an excellent model with which Werner created his famous coordination theory. Perhaps polymer compounds of ruthenium will serve as a model for creating the theory of inorganic polymers.
Problem #3: obtaining and using ruthenium
Despite its low occurrence in nature and the limited scale of ruthenium mining, this element cannot be called unemployed.
Ruthenium is the most base of the platinum metals, but it shares most of their properties. Moreover, it also has a number of specific properties. Every year the areas of application of ruthenium are expanding more and more. In this regard, problem No. 3 arises, diametrically opposite to problem No. 1 - how to increase the production of ruthenium, find new, more effective ways of extracting it from semi-products of copper-nickel production, where this element is present together with other noble and base metals. In this case, problem No. 2 comes back on the agenda. Indeed, in order to effectively extract ruthenium, you need to have a good knowledge of the chemistry of its compounds, their behavior in solutions and various processes. Using electrochemical methods, extraction and precipitation, we learned to isolate and separate ruthenium from all accompanying elements.
Where is ruthenium used and what are the prospects for its use?
Ruthenium, like platinum and palladium, has catalytic properties, but often differs from them in greater selectivity and selectivity. Heterogeneous catalysis uses the metal ruthenium and its alloys. The most effective catalysts are obtained by depositing ruthenium on various supports with highly developed surfaces. In many cases it is used together with platinum in order to increase its catalytic activity. An alloy of rhodium, ruthenium and platinum accelerates the oxidation of ammonia in the production of nitric acid. Ruthenium is used for the synthesis of hydrocyanic acid from ammonia and methane, to obtain saturated hydrocarbons from hydrogen and carbon monoxide. A method for the polymerization of ethylene on a ruthenium catalyst has been patented abroad.
Ruthenium catalysts have become important for the reaction of producing glycerol and other polyhydric alcohols from cellulose by hydrogenation. The famous Soviet scientist academician A.A. Balandin and his collaborators, using ruthenium, were able to transform sawdust, corn cobs, sunflower seed husks and cotton bolls into valuable chemical products. There was a report in the press that a ruthenium catalyst had been successfully used in the synthesis of diamonds.
Organometallic compounds of ruthenium are used in homogeneous catalysis for various hydrogenation reactions, and in terms of selectivity and catalytic activity they are not inferior to recognized rhodium-based catalysts.
The main advantage of the ruthenium catalyst is its high selectivity. It is this that allows chemists to use ruthenium to synthesize a wide variety of organic and inorganic products. Ruthenium catalyst is beginning to seriously compete with platinum, iridium and rhodium.
Element No. 44 is somewhat less capable in metallurgy, but it is also used in this industry. Small additions of ruthenium usually increase the corrosion resistance, strength and hardness of the alloy. Most often it is introduced into metals from which contacts for electrical engineering and radio equipment are made. An alloy of ruthenium and platinum has found application in the fuel cells of some American artificial Earth satellites. Alloys of ruthenium with lanthanum, cerium, scandium, and yttrium have superconductivity. Thermocouples made from an alloy of iridium and ruthenium can measure the highest temperatures.
Much can be expected from the use of ruthenium coatings applied in the form of a thin layer (film) on various materials and products. Such a film significantly changes the properties and quality of products, increases their chemical and mechanical resistance, makes them corrosion-resistant, dramatically improves electrical properties, etc. Thin coatings made of noble metals, including ruthenium, have become increasingly important in recent years in various fields of electronics, radio and electrical engineering, the chemical industry, and also in jewelry.
An interesting property of ruthenium metal - sorbing and passing hydrogen - can be successfully used to extract hydrogen from a mixture of gases and obtain ultra-pure hydrogen.
Many ruthenium compounds have beneficial properties. Some of them are used as additives in glass and enamels as permanent dyes; ruthenium chlorides, for example, increase the luminescence of luminol, ruthenium polyamines have fluorescent properties, Na 2 · 2H 2 O salt is a piezoelectric, RuO 4 is a strong oxidizing agent. Many ruthenium compounds have biological activity. In some cases they cause allergic reactions and eczema, but there are cases described where they are used to treat skin diseases and cancer. It has been suggested that in living nature, ruthenium compounds serve as catalysts in the processes of binding molecular nitrogen from the air into amino acids.
And finally, speaking about the use of ruthenium, one cannot fail to mention the use of its radioactive isotopes in scientific research, especially in resolving controversial issues of the chemistry of ruthenium itself. Here element #44 ultimately fights with and for itself. After all, the path to the final solution to the problem of purifying nuclear fuel from radioruthenium and the development of methods for effectively extracting ruthenium from ores pass through an in-depth knowledge of the properties and features of this complex and unusual element.
"Eternal" feather
Fountain pen nibs constantly rub against the paper and therefore wear off. To make the pen truly “eternal”, the tip is soldered. Some alloys for soldering “eternal” feathers include ruthenium. In addition to it, these alloys contain tungsten, cobalt, and boron.
Ruthenium is also used in the manufacture of alloys for compass needle supports. These alloys must be hard, strong and resilient. Among natural minerals, the very rare osmic iridium has such properties. Artificial materials for compass needles, along with osmium and iridium, and sometimes other metals, include element No. 44 - ruthenium.
There is contact!
In electrical engineering, copper has long been used for contacts. It is an ideal material for transmitting strong currents. So what if after a certain time the contacts become coated with copper oxide? You can wipe them with sandpaper and they will shine again, like new ones. It's a different matter in low-current technology. Here, any oxide film on the contact can disrupt the operation of the entire system. Therefore, contacts for low currents are made of palladium or a silver-palladium alloy. But these materials do not have sufficient mechanical strength. The addition of small amounts of ruthenium (1...5%) to the alloys gives the contacts hardness and strength. The same applies to sliding contacts, which must resist abrasion well.
Ruthenium red
This is the name of an inorganic dye, which is complex ammonia chloride of ruthenium. Several formulas for this substance have been proposed, but none of them accurately reflects its composition. This dye is not used for dyeing fabrics - it is too expensive. Ruthenium red is used in studies in anatomy and histology (the science of living tissue). A solution of this dye, when diluted 1:5000, colors pectin substances and some fabrics in pink and red tones. Thanks to this, the researcher is able to distinguish these substances from others and better analyze the section examined under the microscope.