Palladium is silver white metal, which outwardly resembles silver and, to a lesser extent, platinum. In terms of density (12.02 g/cm3), palladium is also closer to silver, whose density is 10.49 g/cm3, than to platinum, whose density is 21.40 g/cm3.

Palladium is the lightest of the platinides. It is easiest to melt, the required temperature is 1552 ° C, in order to boil liquid palladium, a temperature of 3980 ° C is needed. Before melting, it becomes soft and lends itself well to welding and forging. However, even at room temperature, palladium can be easily processed because it is soft.

When using palladium in technology, an important role is played by the variability of its main mechanical characteristics. For example, its hardness increases by 2-2.5 times as a result of cold forging.

A great influence on palladium has a connection with related metals. Its standard tensile strength is 18.5 kg/mm2. However, when 1% rhodium and 4% ruthenium are added to the alloy, it doubles (by the way, this is the version of the alloy used by jewelers).

Usually, stamping and cold rolling are used to make something from palladium. It is relatively easy to obtain seamless tubes with the desired diameter and length from it.

The chemical properties of this metal are no less attractive than the mechanical ones. Palladium is the only metal in which the outer electron shell is extremely filled, which gives it a very high chemical resistance. In the outer orbit of its atom, there are 18 electrons, as a result of which, at normal temperature, palladium is not subject to the destructive action of fluorine.

However, the nobility of palladium, as well as in the case of other noble metals, has a limit - when the temperature begins to exceed 500 ° C, it becomes susceptible to the action of fluorine and other strong oxidizing agents.

In compounds, palladium is most often divalent, but it can also be tri- or tetravalent. Like other platinum metals, palladium can form many thousands of complex compounds that have and practical use, for example, to obtain palladium itself.

Their distinctive feature from the same compounds of other platinum metals is that the complexes of bivalent palladium with many organic compounds (thiourea, oximes, amines) have a flat square structure, while the rest, as a rule, have a bulk octahedral structure.

Application in the jewelry industry

Palladium has its own beauty, in the frame of it look beautiful gems. Among its features is that it lends itself well to polishing, does not corrode and does not tarnish.

With the help of palladium, gold is “whitewashed” (discolored), and one part of palladium falls on six parts of gold. One of the popular uses of the resulting "white gold" is the manufacture of watch cases.

Replacement for platinum

One of the most valuable properties palladium - its relative cheapness. Because of this, it is one of the most (if not the most) promising of the entire spectrum of platinum metals. At present, with the addition of this metal, some alloys, for example, those used for the manufacture of dentures, are made cheaper.

Once upon a time, palladium was extracted in tiny amounts from raw platinum, but now it is obtained in tens of tons per year. Its availability, in comparison with other platinum metals, leads to an increasing use of palladium in engineering. Now they are often replaced with platinum, in cases where this is possible.

Now most of all palladium is used in chemistry and electrical engineering.

History of palladium

Mr. Forster, a well-known mineral dealer in London, expressed little surprise when, on a slushy autumn day in 1803, he received a letter from a person who wished to remain anonymous. On expensive paper, in beautiful handwriting, a request was made: to try to sell a small amount of the new metal palladium, neither in appearance nor in properties inferior to precious platinum. A small and not very heavy ingot was attached to the letter.

At that time, among the British analytical chemists, most of them traditionally stiff or phlegmatic, Richard Cheneviks stood out. An Irishman by birth, a quick-tempered and quarrelsome person, he was especially eager to expose the "fraudulent trick" and, neglecting the high price, bought a palladium bar and began to analyze it.

Bias took its toll: very soon Chenevix became convinced that the metal named palladium "was not new element, as shamefully stated, "but just an alloy of platinum and mercury. Chenevix immediately expressed his opinion - first in a report read before members of the Royal Society of London, and then in print.

However, other chemists, with all their diligence, could not find either mercury or platinum in palladium ... The Secretary of the Royal Society (founded back in 1622 and acting as the English Academy of Sciences) at that time was William Hyde Wollaston. A passionate opponent of routine and patterns in science, from time to time he intervened in a protracted dispute and skillfully aggravated it.

Passions around palladium either heated up or weakened, and when, finally, the new element (or pseudo-element) was already beginning to bother everyone, an anonymous announcement appeared in the most famous scientific journal in England, Nicholson's Journal. who will prepare artificial palladium within a year.

Interest in the new metal jumped again. But all attempts to artificially prepare palladium invariably ended in failure. Only in 1804 did Wollaston report to the Royal Society that he had discovered palladium and another new one in raw platinum. noble metal- rhodium.

And in February 1805, in an open letter published in Nicholson's Journal, Wollaston admitted that the scandalous hype around palladium was also the work of his hands. It was he who put the new metal on sale, and then established a prize for its artificial preparation And by that time he already had irrefutable evidence that palladium and rhodium were indeed new platinum-like metals.

About the discoverer of palladium

The life of William Hyde Wollaston fell exactly on the years in which England became a country of classical capitalism. The industrial revolution, which began here in the 60s of the 18th century, gave rise to a rapid growth in production. The capture of the colonies acquired unprecedented proportions.

The London physician Wollaston practiced in working-class areas. He could not complain about the lack of patients (who, however, had nothing to pay for visits) - their number was growing rapidly. But the art of the doctor, and the medicines with which he generously endowed his patients, often remained powerless against hunger, chronic and occupational diseases.

Disillusioned with medical practice, Wollaston left medicine forever and from 1800. devoted himself entirely to the study of platinum. For life, for the purchase of materials and equipment for the laboratory, money was needed.

H A highly gifted and enterprising man, Wollaston developed a method for making platinum dishes and equipment: a retort for thickening sulfuric acid, vessels for separating silver and gold, standards of measures, etc. Moreover, he, speaking in the current language, quickly introduced this method into practice. And just in these years, platinum glassware became a necessity for chemical laboratories.

The eminent German chemist Justus Liebig will well say about this, although a little later, in his "chemical letters": "Without platinum, it would be impossible in many cases to analyze minerals ... The composition of most minerals would be unknown." And it's not just about minerals: the first quarter of the 19th century. - a time of great change in chemistry. Freed from the shackles of the phlogiston theory, chemistry moved forward by leaps and bounds. It is no coincidence that at the turn of the 18th and 19th centuries. (±10 years) about 20 new chemical elements were discovered.

The Wollaston business flourished; the products that came out of his workshop were in great demand in many countries, were out of competition and brought considerable income to Wollaston the entrepreneur.

However, success in commerce did not go to his head. Among the few scientists of that time, Wollaston understood and consistently put into practice the idea of ​​a mutually fruitful connection between science and practice. Working on further improvement of the methods of refining and processing of platinum, he came to the idea of ​​the possibility of the existence of platinum-like metals.

The salable platinum that Wollaston worked with was contaminated with gold and mercury. In an effort to obtain a purer metal, Wollaston got rid of these, and other impurities. He dissolved raw platinum in aqua regia, after which he precipitated only platinum from the solution - with especially pure ammonia NH4Cl.

Then he noticed that the solution remaining after the precipitation of platinum was pink. Known impurities (mercury, gold) could not explain this color. Wollaston acted on the colored solution with zinc: a black precipitate fell out. After drying it, Wollaston tried to dissolve it in aqua regia. Some of the powder dissolved, and some remained undissolved.

About his further research, Wollaston wrote: “After diluting this solution with water, in order to avoid the precipitation of insignificant amounts of platinum remaining in the solution, I added potassium cyanide to it - a copious precipitate formed. orange color, which, when heated, acquired grey colour... Then this sediment melted into a droplet along specific gravity less mercury ... Part of this metal was dissolved in nitric acid and had all the properties of palladium put on sale. ”Another platinoid, rhodium, was isolated from the other, insoluble part.

Why did Wollaston call the first of the discovered satellites of platinum palladium, and the second - rhodium? Rhodium - from Greek - "pink"; rhodium salts are added to the solution pink color. The second name is not connected with chemistry. It testifies to Wollaston's interest in other sciences, in particular astronomy.

Shortly before the discovery of palladium and rhodium (in 1802), the German astronomer Olbers discovered in solar system a new asteroid and in honor of the ancient Greek goddess of wisdom, Pallas Athena, he named it Pallas. And Wollaston named one of his elements in honor of this asteroid, more precisely, in honor of this astronomical discovery.

On the sources of palladium - real, promising and unpromising

Wollaston had to extract palladium from raw platinum, along the way mined during the washing of gold sands in distant Colombia. At that time, grains of native platinum were the only famous people mineral containing palladium. About 30 minerals are now known to contain this element.

Like all platinum group metals, palladium is quite rare. Although with what to compare! It is calculated that in earth's crust its 1 10–6%, i.e. about twice as much as gold.

The largest placer deposits of platinum metals, and hence palladium, are located in our country (Urals), Colombia, Alaska and Australia. Small impurities of palladium are often found in gold sands. But the main supplier of this metal was the deposits of nickel and copper sulfide ores.

And, of course, processing such ores, precious palladium is extracted as a by-product. Extensive deposits of such ores have been found in the Transvaal (Africa) and Canada. Explored in recent decades, the richest deposits of copper-nickel ores in the Arctic (Norilsk, Talnakh) have discovered great opportunities to further increase the production of platinum metals and primarily palladium.After all, its content in such ores is three times greater than that of platinum itself, not to mention its other satellites.

Methods for obtaining pure palladium from natural raw materials based on separation chemical compounds platinum metals are very complex and durable. Foreign refiners are reluctant to share their trade secrets. We, of course, do too. And it hardly makes sense to describe the technology of thirty years ago. Therefore, we will leave technology aside - let's talk more about minerals.

Of the six platinum metals, apart from platinum itself, only palladium occurs in its native state. By appearance it is rather difficult to distinguish it from native platinum, but it is much lighter and softer than it.

Chemical analysis shows that native palladium usually contains impurities: primarily platinum itself, and sometimes also iridium, silver and gold. But native palladium is extremely rare. Palladium platinum was found in the ores of Norilsk. In its composition, identified with the help of a microanalyzer, 40% palladium.

Back in 1925, the mineral potarite was found in the diamond placers of British Guinea. Its PdHg composition was established by conventional chemical analysis: 34.8% Pd and 65.2% Hg. However, the existence of other compounds of palladium with mercury is also possible, for example, Pd2Hg3.

In Brazil, in the state of Minas Gerais, a very rare and still insufficiently studied variety of native gold was found - palladium gold (or porpecite). Palladium in it is only 8 ... 11%. In appearance, this mineral is difficult to distinguish from pure gold.

These are some minerals of palladium. By the way, palladium was also found in meteorites: 1.2 ... 7.7 g / t of the substance of iron meteorites and up to 3.5 g / t - in stone. And on the Sun, it was discovered simultaneously with helium back in 1868.

named after Wollaston

Among the insignia that marked the works of prominent world scientists, there is a Wollaston medal made of pure palladium. Established almost 150 years ago by the Geological Society of London, it was first minted in gold; then in 1846, the famous metallurgist Johnson extracted pure palladium from Brazilian palladium gold, destined exclusively for the manufacture of this medal.

Charles Darwin was among the recipients of the Wollaston Medal. In 1943, the medal was awarded to Academician Alexander Evgenievich Fersman for his outstanding mineralogical and geochemical studies. Now this medal is kept in the State Historical Museum.

Palladium - hydrogen purifier

Fail-safe signaling device

Carbon monoxide CO is called carbon monoxide for a reason. This poison is doubly dangerous because it has no color, no taste, no smell. To determine the presence of CO in the air, you can use a piece of paper moistened with a solution of palladium chloride. This is a fail-safe signaling device; as soon as the CO content in the air exceeds the permissible value (0.02 mg/l), the paper turns black - PdCl2 is reduced to palladium black.

Palladium is one of the elements of the periodic table, which is part of the platinum group.

The history of the discovery of palladium and its presence in nature, the biological, chemical and physical properties of palladium, the use of palladium in the jewelry industry, in palladium, the production of palladium, facts about palladium

Palladium is, definition

Palladium is extremely heavy and very refractory ductile and malleable, which is very easily rolled into foil and drawn into thin wire. In terms of density, which is 12 g/cm3, palladium is still closer to silver, whose density is 10.5 g/cm3, than to related platinum (21 gcm3). Palladium occurring in nature consists of six stable isotopes: 102Pd (1.00%), 104Pd (11%), 105Pd (22%), 106Pd (27%), 108Pd (26%) and 110Pd (11%). The longest-lived and artificial radioactive isotope is 107Pd with a half-life of more than seven million years. Many isotopes of palladium are produced in small amounts in the fission of uranium and plutonium nuclei. In modern nuclear reactors 1 ton of nuclear fuel with a burnup of 3% contains about 1.5 kilograms of palladium.

Palladium (Palladium) is

Palladium is one of the elements periodic system chem. elements named after Mendeleev. In the table, this element has serial number 46 and is located in the fifth period elements.

Palladium is noble metals belonging to the platinum group. By itself it has a white - silver color.

Palladium is the only chemical element with an extremely filled outer electron shell. There are 18 electrons in the outer orbit of the palladium atom.

Paladin is an element that is often used in the production of white gold or as the base of a palladium alloy. Even 1-2% palladium is enough to gold acquired a silvery-white tint. But mostly white gold 583 samples contain 13% palladium. It is most suitable for setting diamonds.

Palladium is an element that can enhance the anti-corrosion properties of even such a resistant to aggressive media metal, how . The addition of palladium in just 1% increases the resistance to sulfuric and hydrochloric acids.

Paladin is the material from which most of the medals awarded to outstanding scientists, as well as athletes, are made.

The history of the discovery of palladium

Palladium was discovered by the English physician and chemist William Wollaston in 1803 while studying raw platinum, brought from the burning continent, in that part of it that is soluble in aqua regia. Having dissolved the ore, Wollaston neutralized the acid with a solution of NaOH, after which he precipitated platinum from the solution by the action of ammonium chloride NH4Cl (ammonium chloroplatinate precipitates). Mercury cyanide was then added to the solution to form palladium cyanide. Pure palladium was isolated from cyanide by heating. Only a year later, Wollaston reported to the Royal Society that he had discovered palladium and another new noble metal, rhodium, in raw platinum. The very name of the new element - palladium (Palladium) Wollaston derived from the name minor planet Pallas (Pallas), discovered shortly before (1801) by the German astronomer Olbers.

The forty-sixth element, due to a number of its remarkable physical and chemical properties, found wide application in many areas of science and life. So some types of laboratory glassware are made from palladium, as well as parts of equipment for separating hydrogen isotopes. Alloys of palladium with other metals find a very valuable application. For example, alloys of the forty-sixth element with silver used in communication equipment (contact manufacturing). Temperature controllers and thermocouples use alloys of palladium with gold, platinum and rhodium. Certain alloys of palladium are used in jewelry, dentistry (dentures) and even used to make parts for pacemakers.

When applied to porcelain, asbestos and other supports, palladium serves as a catalyst for a number of redox reactions, which is widely used in the synthesis of a number of organic compounds. Palladium is used to purify hydrogen from traces of oxygen, as well as oxygen from traces of hydrogen. Palladium chloride solution is an excellent indicator of the presence carbon monoxide in the air. Palladium coatings are applied to electrical contacts to prevent sparking and increase their corrosion resistance (palladium).

In the jewelry trade, palladium is used both as a component of alloys and by itself. In addition, the Russian Central Bank mints palladium commemorative coins in very limited quantities. A small amount of palladium is consumed for medical purposes - the preparation of cytostatic drugs - in the form of complex compounds, similar to cis-platinum.

The honor of discovering palladium belongs to the Englishman William Hyde Wollaston, who isolated a new one from the crude platinum of South American mines in 1803. Who is the man who is named after the pure palladium medal awarded annually by the Geological Society of London?

At the end of the eighteenth century, William Wollaston was one of the many obscure London doctors who practiced in poor working-class areas. A job that did not bring income could not suit a smart and enterprising young man. In those days, the doctor had to have the skills not only of a physician, but also to master the pharmaceutical business, which in turn required an excellent knowledge of chemistry. W.H. Wollaston turned out to be an excellent chemist - studying platinum, he invented new way manufacture of platinum tableware and set up its production. It is worth mentioning that in those years, platinum glassware for chemical laboratories was a necessity, because the hype around scientific discoveries was the same as in the time of the alchemists around the philosopher's stone. It is no coincidence that at the turn of the XVIII and XIX centuries. discovered about 20 new chemical elements!

Indeed, the creation of new exchange-traded funds, which themselves have become active buyers of platinum, remains one of the main factors behind the significant rise in the price of platinum. Since the properties and applications of palladium and platinum largely coincide, the markets for these metals are interconnected, which means that we can expect a similar reaction of the palladium market to the activities of funds.

Palladium (Palladium) is

Such assumptions are confirmed by Stuart Flerlidzh (Stuart Flerlage) from the New York company NuWave Investment: “the prices for platinum are rising higher and higher ... Perhaps we will have the same picture with valuable palladium.” The creation of exchange-traded funds pegged to platinum could further spur demand for the metal, prompting more manufacturers and jewelers to turn their eyes to yet more affordable palladium, said Michael Gambardella, JP Morgan and Co. (JPM). “We expect the large price gap between the two metals to close,” adds Gambardella.

Sources and links

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Encyclopedia of the investor. 2013 . - I, husband. Father: Palladyevich, Palladievna and Palladyevich, Palladievna. Derivatives: Paladya; Lada (Rook); Palya; Broadsword; Pasha. Origin: (Greek Palladion palladium (the image of Pallas Athena, according to legend, fell from the sky as a guarantee of her immunity ... Dictionary of personal names

PALLADIUM- (Greek). A metal similar to silver is found in platinum ore and is used in the manufacture of astronomical and physical instruments. Dictionary foreign words included in the Russian language. Chudinov A.N., 1910. Noble PALLADIUM ... ... Dictionary of foreign words of the Russian language

PALLADIUM- (Palladium), Pd, chemical element of group VIII of the periodic system, atomic number 46, atomic mass 106.42; refers to platinum metals, mp 1554 shC. Palladium and its alloys are used to make medical instruments, dentures, crucibles for ... ... Modern Encyclopedia

I. Palladium, Palladios, ca. 363 425 n. e., Greek Christian historian and hagiographer. Born in Galatia. After graduating in 386, he became a monk, first in Palestine, then in Egypt, from where he made numerous travels around ... ... Ancient writers

metal silvery white color, ductile and malleable, easily rolled into foil and pulled into thin wire. Density of palladium 12.2; melting point 1552 deg. FROM; Mohs hardness 5. In air at normal temperature, palladium ... Official terminology

- (Palladium), Pd, chemical element of group VIII of the periodic system, atomic number 46, atomic mass 106.42; refers to platinum metals, mp 1554 °C. Palladium and its alloys are used to make medical instruments, dentures, crucibles for ... ... Illustrated Encyclopedic Dictionary

PALLADIUM- in Greek mythology small wooden statue of the goddess Athena. She was kidnapped by Odysseus and Diomedes. According to Virgil's Aeneid, the original palladium was taken by Aeneas to Italy after the fall of Troy... Big Encyclopedic Dictionary

PALLADIUM- (symbol Pd), a silvery white TRANSITION ELEMENT, a metal first discovered in 1803. Malleable, machinable palladium is found in nickel ores. Refers to platinum metals and has common chemical characteristics with PLATINUM. Not … Scientific and technical encyclopedic dictionary

A small wooden statue of the goddess Athena. She was abducted from Troy by Odysseus and Diomedes. According to Virgil's Aeneid, after the fall of Troy, genuine palladium was taken by Aeneas to Italy. (

Palladium was discovered in 1803 by W. H. Wollaston while studying native platinum.

The London physician Wollaston practiced in working-class areas. He could not complain about the lack of patients (who, however, had nothing to pay for visits) - their number was growing rapidly. But the art of the doctor, and the medicines with which he generously endowed his patients, often remained powerless against hunger, chronic and occupational diseases.

Disillusioned with medical practice, Wollaston abandoned medicine forever and from 1800 devoted himself entirely to the study of platinum. For life, for the purchase of materials and equipment for the laboratory, money was needed. A highly gifted and enterprising man, Wollaston developed a method for making platinum dishes and equipment: a retort for thickening sulfuric acid, vessels for separating silver and gold, standards of measures, etc. Moreover, he, speaking in the current language, quickly introduced this method into practice. And just in these years, platinum glassware became a necessity for chemical laboratories. The eminent German chemist Justus Liebig will well say about this, although a little later, in his “chemical letters”: “Without platinum, it would be impossible in many cases to analyze minerals ... The composition of most minerals would be unknown.” And it's not just about minerals: the first quarter of the 19th century. - a time of great change in chemistry.

The Wollaston business flourished; the products that came out of his workshop were in great demand in many countries, were out of competition and brought considerable income to Wollaston the entrepreneur. However, success in commerce did not go to his head. Among the few scientists of that time, Wollaston understood and consistently put into practice the idea of ​​a mutually fruitful connection between science and practice.

Working on further improvement of the methods of refining and processing of platinum, he came to the idea of ​​the possibility of the existence of platinum-like metals. The salable platinum that Wollaston worked with was contaminated with gold and mercury. In an effort to obtain a purer metal, Wollaston got rid of these, and other impurities. He dissolved raw platinum in aqua regia, after which he precipitated only platinum from the solution - with especially pure ammonia NH 4 Cl. Then he noticed that the solution remaining after the precipitation of platinum was pink. Known impurities (mercury, gold) could not explain this color.

Wollaston acted on the colored solution with zinc: a black precipitate fell out. After drying it, Wollaston tried to dissolve it in aqua regia. Some of the powder dissolved, and some remained undissolved. About his further studies, Wollaston wrote: “After diluting this solution with water, in order to avoid the precipitation of small amounts of platinum remaining in the solution, I added potassium cyanide to it - an abundant orange precipitate formed, which turned gray when heated ... Then this precipitate melted into a droplet in terms of specific gravity less than mercury ... Part of this metal was dissolved in nitric acid and had all the properties of palladium put on sale. Another platinoid, rhodium, was isolated from the other, insoluble part.

Why did Wollaston call the first of the discovered satellites of platinum palladium, and the second - rhodium? Rhodium - from the Greek ροδοεις - "pink"; rhodium salts give the solution a pink color. The second name is not connected with chemistry. It testifies to Wollaston's interest in other sciences, in particular astronomy. Shortly before the discovery of palladium and rhodium (in 1802), the German astronomer Olbers discovered a new asteroid in the solar system and named it Pallas in honor of the ancient Greek goddess of wisdom, Pallas Athena. And Wollaston named one of "his" elements in honor of this asteroid, more precisely, in honor of this astronomical discovery.

INTRODUCTION

Spent palladium catalysts usually contain up to 2% Pd; the rest is Activated carbon, aluminum oxide and various impurities such as very fine sand, metallic soaps and high molecular weight substances.

One of the most common methods for recovering palladium from spent catalysts is to burn the catalyst in a furnace to form ash, in which the concentration of palladium reaches 15–20%, and a small amount of carbon, often in the form of graphite.

PALLADIUM AND ITS PROPERTIES

Origin of the name palladium

It is named after the asteroid Pallas, discovered by the German astronomer Olberts in 1802, that is, shortly before the discovery of palladium. In turn, the asteroid is named after Pallas (Athena Pallas or her friend Pallas) from ancient Greek mythology. Palladium is a legendary wooden image of Pallas Athena that fell from the sky. It was one of the conditions for the invincibility of Troy. Troy fell only after the goddess's favorites, Odysseus and Diomedes, stole the palladium during a night outing.

History of palladium

Among the many insignia awarded to outstanding scientists, there is one medal, which is made of pure palladium. This is the Wollaston Medal, awarded annually by the Geological Society of London. What made William Hyde Wollaston so famous? Back in the late eighteenth century, he was an obscure London doctor. At that time, many doctors were also pharmacists, and therefore chemists. Wollaston turned out to be a good chemist, he invented a new method for making platinum dishes and set up its production.

Having thus become rich, Wollaston left the practice of medicine forever and devoted himself to chemistry and mineralogy. His main scientific task was the extraction of platinum from ores and its purification. During the study, Wollaston separated and analyzed its impurities. The result of these works was the discovery of palladium and rhodium. Wollaston had to extract palladium from raw platinum, incidentally mined during the washing of gold sands in the distant Colombian Republic. At that time, grains of native platinum were the only mineral known to people that contained palladium. About 30 minerals are now known to contain this element. To isolate the element, Wollaston dissolved the ore in aqua regia (aqua regia), neutralized the acid with a NaOH solution, then precipitated platinum from the solution by the action of ammonium chloride NH4Cl (ammonium chloroplatinate precipitated). Mercury cyanide was then added to the solution to form palladium cyanide. Pure palladium was isolated from cyanide by heating.

Distribution of palladium

Like all platinum group metals, palladium is not widely used. Although with what to compare! It is estimated that in the earth's crust it is 1 10-6%, i.e. about twice as much as the yellow metal. The largest placer deposits of platinum metals, and, consequently, of palladium, are located in our country (the Urals), in the Republic of Columbia, in Alaska and in Australia. Small impurities of palladium are often found in gold sands.

But the main supplier of this metal was the deposits of nickel and cuprum sulfide ores. And, of course, processing such ores, precious palladium is extracted as a by-product. Extensive deposits of such ores have been found in the Transvaal (Africa) and the Maple Leaf Country.

Explored in recent decades, the richest deposits of copper-nickel ores in the Arctic (Norilsk, Talnakh) have opened up great opportunities for further increasing the production of platinum metals, and primarily palladium. After all, its content in such ores is three times greater than that of platinum itself, not to mention its other satellites.

Of the six platinum metals, apart from platinum itself, only palladium occurs in its native state. In appearance, it is rather difficult to distinguish it from native platinum, but it is much lighter and softer than it. Chemical analysis shows that native palladium usually contains impurities: primarily platinum itself, and sometimes also iridium, silver and gold. But native palladium is extremely rare.

Minerals containing element No. 46 are its compounds with lead, tin (intermetallic compounds), arsenic, sulfur, bismuth, tellurium. Approximately a third of these minerals are still insufficiently studied and do not even have names. This is explained by the fact that the minerals of all platinum metals form microinclusions in ores and are difficult to study. The composition of some of these microinclusions was deciphered by a magnificent device - an X-ray microanalyzer. It can be used to determine chemical composition samples weighing only 10-14 g!

One of the interesting minerals of element #46 is allopalladium, the nature of which is still being studied. This silvery-white mineral with a metallic luster is very rare. Spectral analysis found that it contains mercury, platinum, ruthenium, copper. But it has not yet been possible to decipher the composition of this mineral.

Palladium platinum was found in the ores of Norilsk. In its composition, identified with the help of a microanalyzer, 40% palladium.

Back in 1925, the mineral potarite was found in the diamond placers of British Guinea. Its PdHg composition was established by conventional chemical analysis: 34.8% Pd and 65.2% Hg. However, the existence of other compounds of palladium with mercury is also possible, for example, Pd2Hg3.

In Brazil, in the state of Minas Gerais, a very rare and still insufficiently studied variety of native yellow metal, palladium gold (or porpecite), was found. Palladium in it is only 8 ... 11%. In appearance, this mineral is difficult to distinguish from pure yellow metal.

These are some minerals of palladium. By the way, palladium was also found in meteorites: 1.2 ... 7.7 g / t of the substance of iron meteorites and up to 3.5 g / t - in stone ones. And on the Sun, it was discovered simultaneously with helium back in 1868.

oh, but with a mixture of six elements - platinum metals, which by that time had not been discovered. For example, when osmium was absent in platinum, the metal was not volatile and did not catch fire; in the presence of osmium, the alloy was volatile and burned.

What year is considered the date of discovery of platinum? Metal has come a long way before it got the right to exist. May be, important date in the history of the discovery of platinum in 1750, after all, it was then that it was studied and described in sufficient detail.

pdllddjai

Even at the end of the XVI century. Brazilian miners have repeatedly discovered a strange alloy in nature. He appeared under different names. It was supposed to contain gold and silver. Perhaps it was an alloy of palladium and gold. But the real discovery of the second of the platinum metals took place in 1803, thanks to the work of the English chemist W. Wollaston. While studying raw (unrefined) platinum, he dissolved it in aqua regia, removed the excess acid, and added mercury cyanide to the solution. A yellow precipitate fell out. By heating it with sulfur and borax, W. Wollaston obtained shiny metal balls. He named the new metal palladium (in honor of open year formerly by astronomer W. Olbers asteroid Pallas). The success of W. Wollaston is largely due to the fact that he correctly found the palladium precipitant - mercury cyanide, which does not precipitate other platinum metals.

The discovery of palladium received publicity in a rather curious way. The young Irish chemist R. Chenevyaks in 1804 advertised in the Journal chemical education about some "new metal for sale" that represented co. an alloy of platinum with mercury. W. Wollaston, of course, did not agree with this opinion and defended his discovery with the article "On a new metal found in raw platinum." In it, he emphasized that the metal offered for sale (an allusion to the words of Chenevix. - Aug.), called palladium, is contained in platinum ores, although in small proportions.

Contemporaries (including L. Vauquelin) highly appreciated the achievement of W. Wollaston, especially since this scientist soon discovered another platinum metal - rhodium. The primacy of palladium isolation can probably be explained by the fact that it is the most common platinum metal. In addition, it is found in nature in its native state. This was shown (on the example of Brazilian platinum ores, which were the only source of research before the discovery of Ural platinum) in 1809 by W. Wollaston, and in 1825 by A. Humboldt.

Palladium served as the key to the discovery of relatives, which occurred at the turn of 1803 - 1804, that is, even before the news of palladin penetrated into wide circles.

Raw platinum was also a source of relatives, of course, from deposits South America. It is only unknown whether this was the same sample in which W. Wollaston discovered palladium. After dissolving a portion of crude platinum in aqua regia and neutralizing the excess acid with alkali, the discoverer Palladin first added an ammonium salt to precipitate the platinum as ammonium chloroplatinate. Mercury cyanide was added to the remaining solution (this is where skills in isolating palladium came in handy), palladium cyanide turned out to be in the sediment. After cleaning the solution from excess mercury cyanide and evaporating the solution to dryness, W. Wollaston observed a beautiful dark red precipitate, which, in his opinion, was double sodium chloride and a new metal.

This salt readily decomposed when heated in a stream of hydrogen, leaving behind a metal powder after removal of the sodium chloride. The scientist also prepared a new metal in the form of balls. Rhodium got its name in connection with the red color of its first received salt (in Greek, genus means "rose").

This element is perhaps the least common of all the platinum metals. For him, only one own mineral is known - will give birth, found in the gold-bearing sands of Brazil and Colombia. At the same time, several minerals are known for other platinum metals.

OSMIA AND IRIDIUM

Until now, there has never been a case in the history of science when, in the course of two years, in one country, in England, four new elements were discovered at once, and, moreover, similar in properties. Simultaneously with W. Wollaston, his compatriot S. Tennant was engaged in the study of platinum metals. But if the discovery of palladin and relatives belongs to W. Wollaston, then the isolation of osmium and iridium is associated with the names of other scientists, although the merit of S. Tennant is the greatest.