Copper and its properties. Properties of copper and its application. Specific Gravity Units

Synonyms: Thin mixtures of native copper and cuprite were called cuprocuprite (Vernadsky, 1910). Whitneyite (Gent, 1859) and Darwinite (Forbes, 1860) are arsenic copper that forms mixtures with algodonite.

origin of name

The Latin name for copper cuprum comes from the name of the island of Cyprus, from where copper was imported in ancient times. The origin of the Russian name is unclear.

The English name for the mineral Copper is Copper

• Chemical composition
• Varieties
• Form of being in nature
• Physical properties
• Chemical properties. Other properties
• diagnostic signs. Satellites.
• Origin of the mineral
• Place of Birth
• Practical use
• Buy

Formula

Chemical composition

It sometimes contains admixtures of Fe, Ag, Pb, Au, Hg, Bi, Sb, V, Ge 3 (silver copper with 3-4% Ag, iron-2.5% Fe and golden-2-3% Au). Impurities are observed more often in primary native copper; recycled copper is usually purer. The composition of native copper from the Shamlugh deposit (Armenia): Cu - 97.20 -97.46%, Fe - 0.25%; in copper from the Altai deposits, 98.3% Cu and more were determined.

Crystallographic characteristic

Syngony. Cubic.

Class. Hexoctahedral.

Crystal structure

The crystal structure is characterized by a face-centered lattice; copper atoms are located at the corners and in the centers of the faces of the elementary cube. This is a formal expression of the fact that in the structure of copper there is a closest packing (the so-called cubic closest packing) of metal atoms with a radius of 1.27 A and a distance between the nearest atoms of 2.54 A while fulfilling a space of 74.05%. Each Cu atom is surrounded by 12 similar ones (coordination number 12), located around it along the vertices of the so-called Archimedean cuboctahedron.

Main forms:a (100), d (110), o (111), l (530), e (210), h (410).

Form of being in nature

Crystal Shape. The shape of the crystals is cubic, tetrahexahedral, dodecahedral, less often - octahedral (possibly, pseudomorphs after cuprite). The edges are often rough, with depressions or elevations. Simple crystals are rare.

Doubles. Intergrowth twins along (111) are common, sometimes polysynthetic, often lamellar in the axis twin direction or elongated plane twins parallel to the diagonal. Usually crystals (simple and twins) are unevenly developed: elongated, shortened or deformed. Dendritic forms are characteristic, which are uniform intergrowths of many crystals (uniformly deformed or regular) in any one direction. These are, for example, crystals twinned along (111) elongated along the 2nd order symmetry axis and fused parallel to the faces of a rhombic dodecahedron) or intergrowths of regular twinned crystals branching along the edges and diagonals of octahedral faces, as well as parallel intergrowths of crystals elongated in the direction axes of the 4th order. In continuous precipitates of native copper during etching, signs of collective crystallization are found with the development of large grains due to smaller, irregularly shaped zonal grains.

Aggregates. Distorted crystals, in single irregular grains, dendritic intergrowths, filamentous, wiry, mossy formations, thin plates, concretions, powdery accumulations and continuous masses weighing up to several hundred tons.

Physical properties

Optical

The color in the fresh fracture is light pink, quickly changing to copper red, then to brown; often with a yellow or variegated tint.

The line is copper-red, shiny.

Shiny metallic.

Transparency. Opaque. In the thinnest plates, it shines through in green.

Refractive indices

Ng = , Nm = and Np =

Mechanical

Hardness 2.5-3.

Density 8.4-8.9

Cleavage is not observed.

Fracture splintery, hooked.

Chemical properties

Easily soluble in dilute HNO 3 and in aqua regia, in H 2 SO 4 - when heated, in HCl - with difficulty. It dissolves in an aqueous solution of ammonia, turning it blue. In polished sections it can be etched with all major reagents. The internal structure is easily detected using NH 4 OH + H 2 O 2 or HCl + CrO 3 (50% solution).

Other properties

Very malleable and ductile. The electrical conductivity is very high; significantly reduced by impurities.

Behavior on heating. Pure copper melts at 1083°. The thermal conductivity is somewhat less than that of silver.

Artificial production of the mineral.

It can be easily obtained from melts or by electrolysis from solutions of copper salts.

Diagnostic features

Similar minerals

Recognized by the red color of the fresh surface, shiny line, medium hardness and malleability, usually covered with greenish, black, blue deposits of oxidized copper minerals. Under a microscope in reflected light, it is easily determined by color and reflectivity.

Associated minerals. Cuprous gold, chalcocite, calcite, diopside, apatite, sphene, magnetite, malachite, barite, quartz, chalcopyrite.

Origin and location

Hydrothermal. Accumulates in placers. Nuggets weighing up to 450 tons are described as unique phenomena.

Native copper is formed under reducing conditions during various geological processes; a significant part of it is released from hydrothermal solutions. In the form of microscopic segregations, it is observed in many, mainly mafic, igneous rocks exposed to hydrothermal solutions, for example, in serpentinized peridotites, dunites and serpentinites. In this case, the appearance of native copper is possibly associated with the decomposition of previously formed copper sulfides, for example, cubanite (Urals, Transcaucasia). A similar origin can be attributed to native copper in amphibolized basic rocks of the Serov region of the Sverdlovsk region. In the Karabash cuprous gold deposit of the Chelyabinsk region, native copper is observed in vein-like bodies of diopside-garnet rocks occurring among serpentinites; for native copper it is characterized by association with cuprous gold, chalcocite, calcite, diopside, apatite, sphene, magnetite, etc.
In some ancient volcanic rocks (melafirs, diabases, etc.), metamorphosed under the influence of vapors, gases and hydrothermal solutions, copper fills tonsils, forms cement between minerals of altered lava, fills voids and cracks; accompanied by hydrothermal minerals: analcime, lomontite, prehnite, datolite, adularia, chlorite, epidote, pumpeliite, quartz, calcite. The largest deposits of this type are located on the Kivino Peninsula in the Lake Superior region (Michigan, USA), where mineralization is confined to the Upper Proterozoic sequence. The main mass of copper is mined from melafirs and conglomerates, but the largest copper segregations (up to 400 tons and more) are found in calcite veins containing native silver and domeikite.

Mineral change.

The most common alteration products of native copper are cuprite, malachite, and azurite.

Place of Birth

Allocations of native copper were observed in the diabases of Novaya Zemlya, in the traps of the Siberian Platform, among the main effusive rocks in Italy, the Faroe Islands (Denmark), Nova Scotia (Canada) and other places. Representatives of rare types of hypogene deposits of native copper are the Franklin zinc-manganese deposit (New Jersey, USA) and the Longban and Jacobsberg manganese deposits (Sweden). Hypogenic, apparently, are the allocation of native copper weighing up to several tons from the previously developed Kalmaktas deposit in Kazakhstan, presented in museums with excellent samples.
In the oxidation zone, especially in its lower parts, native copper is mainly an early product of the alteration of copper sulfide minerals, mainly chalcocite. It composes predominantly irregularly shaped discharges, less often - crystals and dendritic aggregates.
Most often, native copper is accompanied by chalcocite, cuprite, calcite, and limonite. It is observed in a number of deposits in Kazakhstan (Dzhezkazgan, Berkara, Uspenskoye, etc.), Rudny Altai (Belousovskoye, Zyryanovskoye, Chudak, Talovskoye, etc.), the USA (Bisbee and Clifton-Morensee in Arizona, Tintik in Utah, etc.) .
Part of the native copper in the oxidation zone is formed by deposition from solutions containing copper sulfate. Such, for example, is native copper, which forms precipitates in cavities among limonite aggregates, sometimes in association with cuprite (Copper ore deposit, Sverdlovsk region, etc.). Native copper pseudomorphs are known, formed in the zone of oxidation after chalcocite, cuprite, antlerite, chalcanthite, azurite, calcite, aragonite and other minerals.
Particularly beautiful samples of native copper (crystals and dendritic aggregates) come from the Turin mines of the Sverdlovsk region.
In some mine workings, so-called cement copper is released from copper-containing waters on iron objects in the form of films and crusts. There are also known cases of copper formation on half-decayed remains of fasteners.
In an increased amount, native copper is observed in some sedimentary rocks (sandstones, clays, marls) containing plant remains, in the form of irregularly shaped segregations, sometimes in pseudomorphs on wood or in the form of concretions. Such, for example, are the Permian cupriferous sandstones of certain regions of Russia (the Urals, Tatarstan, etc.), the Naukata sandstones in Kyrgyzstan, and the Cretaceous cuprous sandstones of Korokoro and Kobritsos in Bolivia, and others.
The formation of native copper in some peat bogs is also associated with the recovery processes, for example, in the Sverdlovsk region - along the Lyovikha River in the Tagil River basin and in the Sysert region.
In the form of pebbles and grains, native copper is found in Russia in some placers: in the Urals, along the Yenisei, along the B. Sarkhoy River in Buryatia, along the Chorokh River in Georgia, on the Commander Islands and in other places. In the state of Connecticut (USA), native copper was found in glacial deposits in the form of segregations weighing up to 75 kg. Small, irregularly shaped precipitates of native copper are noted in the native iron of the Vengerovo meteorite in association with troilite.

Practical use

An important component of some copper ores, sometimes the main copper mineral of such ores.

It is used in electrical engineering, instrument making; various alloys with copper (bronze, brass, cupronickel) are widely used.

Physical research methods

Differential thermal analysis

Main lines on radiographs:

ancient methods. It melts under the blowpipe. At a white heat temperature, it gradually oxidizes, turning the flame green.

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Crystal optical properties in thin preparations (sections)

In polished sections in reflected light pink. Reflectivity (in%): for green rays - 61, for orange - 83, for red - 89. Isotropic. Refractive indices (according to Kundt) in prisms for red light - 0.45, for white - 0.65, for blue - 0.95; in reflective light (according to Drude) for Na-light 0.641, for red - 0.580. The absorption coefficient for Na-light is 4.09, for red light - 5.24.

Copper. Somorodok

Metallic copper has long been used by mankind in various areas of life. The twenty-ninth element from the periodic table of D. I. Mendeleev, located between nickel and zinc, has interesting characteristics and properties. This element is denoted by the symbol Cu. It is one of the few metals with a characteristic coloration other than silver and grey.

History of copper

About how great this chemical element had in the history of mankind and the planet, one can already guess from the names of historical eras. After the Stone Age, the copper age came, followed by the bronze age, which is also directly related to this element.

Copper is one of the seven metals that have been known to mankind since ancient times. According to historical data, the acquaintance of ancient people with this metal happened about nine thousand years ago.

The oldest products made from this material were found on the territory of modern Turkey. Archaeological excavations carried out at the site of a large Neolithic settlement called Chatalheyuk made it possible to find small copper beads, as well as copper plates, with which ancient people decorated their attire.

The found gizmos were dated at the turn of the eighth and seventh millennium BC. In addition to the products themselves, slag was found at the excavation site, which indicates that metal was smelted from ore.

Obtaining copper from ore was relatively affordable. Therefore, despite its high melting point, this metal was among the first to be quickly and widely mastered by mankind.

Mining methods

Under natural conditions, this chemical element exists in two forms:

• connections;
• nuggets.

An interesting fact is the following: copper nuggets in nature come across much more often than gold, silver and iron.

Natural copper compounds are:

• oxides;
• carbonic and sulfur complexes;
• bicarbonates;
• sulfide ores.

Ores with the greatest distribution, are copper luster and copper pyrite. Copper in these ores contains only one or two percent. Primary copper is mined in two main ways:

• hydrometallurgical;
• pyrometallurgical.

The share of the first method is ten percent. The remaining ninety belong to the second method.

The pyrometallic method includes a complex of processes. First, copper ores are enriched and burned. Then the raw material is melted into a matte, after which it is blown in the converter. Thus, blister copper is obtained. Its transformation into pure is carried out by refining - first fire, then electrolytic. This is the last stage. Upon completion, the purity of the resulting metal is almost one hundred percent.

The process of obtaining copper by the hydrometallurgical method is divided into two stages.

1. First, the raw material is leached with a weak solution of sulfuric acid.
2. At the final stage, the metal is separated directly from the solution mentioned in the first paragraph.

This method is used when processing only low-grade ores, since, unlike the previous method, it is impossible to extract precious metals along the way. That is why the percentage attributable to this method is so small compared to the other method.

A little about the name

The chemical element Cuprum, denoted by the symbol Cu, got its name in honor of the notorious island of Cyprus. It was there that large deposits of copper ore were discovered in the distant third century BC. Local craftsmen who worked at these mines smelted this metal.

It is perhaps impossible to understand what metallic copper is without understanding its properties, main characteristics and features.

On contact with air, this metal becomes yellowish-pink in color. This unique golden-pink hue is due to the appearance of an oxide film on the surface of the metal. If this film is removed, the copper will acquire an expressive pink color with a characteristic bright metallic sheen.

An amazing fact: the thinnest copper plates in the light are not pink at all, but greenish-blue or, in other words, marine color.

In the form of a simple substance, copper has the following characteristics:

• amazing plasticity;
• sufficient softness;
• ductility.

Pure copper, without the presence of any impurities, is excellent for processing - it can easily be rolled into a bar or sheet, or drawn into a wire, the thickness of which will be brought to thousandths of a millimeter. The addition of impurities to this metal increases its hardness.

In addition to the mentioned physical characteristics, this chemical element has a high electrical conductivity. This feature has mainly determined the use of metallic copper.

Among the main properties of this metal, it is worth noting its high thermal conductivity. In terms of electrical conductivity and thermal conductivity, copper is one of the leaders among metals. Only one metal, silver, has higher rates in these parameters.

It is impossible not to take into account the fact that the indicators of electrical and thermal conductivity of copper belong to the category of basic properties. They remain at a high level only while the metal is in its pure form. It is possible to reduce these indicators by adding impurities:

• arsenic;
• gland;
• tin;
• phosphorus;
• antimony.

Each of these impurities in combination with copper has a certain effect on it, as a result of which the values ​​of thermal and electrical conductivity are noticeably reduced.

Among other things, metallic copper is characterized by incredible strength, a high melting point, and a high boiling point. The data is really impressive. The melting point of copper exceeds one thousand degrees Celsius! And the boiling point is 2570 degrees Celsius.

This metal belongs to the group of diamagnetic metals. This means that its magnetization, like that of a number of other metals, occurs not in the direction of the external magnetic field, but against it.

Another important characteristic is the excellent resistance of this metal to corrosion. Under conditions of high humidity, the oxidation of iron, for example, occurs several times faster than the oxidation of copper.

Chemical properties of the element

This element is inactive. When exposed to dry air under normal conditions, copper does not begin to oxidize. Humid air, on the other hand, triggers an oxidative process that forms copper carbonate (II), which is the top layer of the patina. Almost instantly, this element reacts with substances such as:

• sulfur;
• selenium;
• halogens.

Acids that do not have oxidizing properties are not able to affect copper. In addition, it does not react in any way when in contact with such chemical elements as:

• nitrogen;
• carbon;
• hydrogen.

In addition to the already noted chemical properties, copper is characterized by amphotericity. This means that in the earth's crust it is able to form cations and anions. Compounds of this metal can exhibit both acidic and basic properties - this directly depends on the specific conditions.

Areas and features of application

In ancient times, metallic copper was used to make a wide variety of things. The skillful use of this material allowed the ancient people to acquire:

• expensive dishes;
• decorations;
• thin-bladed tools.

copper alloys

Speaking about the use of copper, one cannot fail to mention its importance in the production of various alloys, which are based on this particular metal. . These alloys include:

• bronze;
• brass.

These two varieties are the main types of copper alloys. The first bronze alloy was created in the East as early as three millennia BC. Bronze can rightfully be considered one of the greatest achievements of the metallurgists of antiquity. In fact, bronze is a combination of copper with other elements. In most cases, tin acts as the second component. But regardless of what elements are included in the alloy, copper is always the main component. The formula of brass contains mainly copper and zinc, but additions to them in the form of other chemical elements are also possible.

In addition to bronze and brass, this chemical element is involved in the creation of alloys with other metals, including aluminum, gold, nickel, tin, silver, titanium, and zinc. Copper alloys with non-metals such as oxygen, sulfur and phosphorus are used much less frequently.

Industries

Valuable properties of copper alloys and pure substance contributed to their use in industries such as:

• electrical engineering;
• electrical engineering;
• instrumentation;
• radio electronics.

But, of course, these are not all areas of application of this metal. It is a highly environmentally friendly material. That is why it is used in the construction of houses. For example, a roof covering made of metallic copper, due to its highest corrosion resistance, has a service life of more than a hundred years, without requiring special maintenance and painting.

Another area of ​​​​use of this metal is the jewelry industry. It is mainly used in the form of alloys with gold. Products made of copper-gold alloy are characterized by increased strength, high durability. Such products do not deform and do not wear out for a long time.

Compounds of metallic copper are distinguished by high biological activity. In the world of flora, this metal is important, as it is involved in the synthesis of chlorophyll. The participation of this element in this process makes it possible to detect it among the components of mineral fertilizers for plants.

Role in the human body

The lack of this element in the human body can have a negative impact on the composition of the blood, namely worsen it. You can fill the deficiency of this substance with the help of specially selected nutrition. Copper is found in many foods, so making a healthy diet to your liking is not difficult. For example, one of the products that contain this element is regular milk.

But when compiling a menu saturated with this element, one should not forget that an excess of its compounds can lead to poisoning of the body. Therefore, saturating the body with this useful substance, it is very important not to overdo it. And this applies not only to the amount of food consumed.

For example, food poisoning can cause the use of copper utensils. Cooking in such dishes is highly discouraged and even prohibited. This is due to the fact that during the boiling process, a significant amount of this element enters the food, which can lead to poisoning.

There is one caveat to the ban on copper utensils. The use of such dishes is not dangerous if its inner surface has a tin coating. Only under this condition, the use of copper saucepans does not pose a threat of food poisoning.

In addition to all the listed branches of application, the spread of this element has not bypassed medicine. In the area of ​​health care and maintenance it is used as an astringent and antiseptic. This chemical element is part of the eye drops, which are used in the treatment of diseases such as conjunctivitis. In addition, copper is an important component of various burn solutions.

Copper is an element of a side subgroup of the first group, the fourth period of the periodic system of chemical elements of D. I. Mendeleev, with atomic number 29. It is designated by the symbol Cu (lat. Cuprum). The simple substance copper (CAS number: 7440-50-8) is a ductile transition metal of a golden pink color (pink in the absence of an oxide film). It has been widely used by man since ancient times.

History and origin of the name

Copper is one of the first metals widely mastered by man due to its comparative availability for obtaining from ore and low melting point. In ancient times, it was used mainly in the form of an alloy with tin - bronze for the manufacture of weapons, etc. (see Bronze Age).
The Latin name for copper Cuprum (ancient Aes cuprium, Aes cyprium) comes from the name of the island of Cyprus, where already in the III millennium BC. e. copper mines existed and copper was smelted.
Strabo calls copper chalkos, from the name of the city of Chalkis on Euboea. Many ancient Greek names of copper and bronze objects, blacksmith craft, blacksmith products and castings originated from this word. The second Latin name for copper is Aes (Sanskrit, ayas, Gothic aiz, German erz, English ore) means ore or mine. Proponents of the Indo-Germanic theory of the origin of European languages ​​derive the Russian word copper (Polish miedz, Czech med) from the Old German smida (metal) and Schmied (blacksmith, English Smith). Of course, the relationship of the roots in this case is undoubted, however, both of these words are derived from the Greek. mine, mine independently of each other. From this word came related names - a medal, a medallion (French medaille). The words copper and copper are found in the oldest Russian literary monuments. The alchemists called copper Venus. In more ancient times, the name Mars is found.

Physical properties

Copper is a golden-pink ductile metal, quickly covered with an oxide film in air, which gives it a characteristic intense yellowish-red hue. Thin films of copper in the light have a greenish-blue color.
Copper forms a face-centered cubic lattice, space group F m3m, a = 0.36150 nm, Z = 4.
Copper has a high thermal and electrical conductivity (ranks second in electrical conductivity after silver).
It has two stable isotopes - 63 Cu and 65 Cu, and several radioactive isotopes. The longest-lived of these, 64 Cu, has a half-life of 12.7 hours and two decay variants with different products.
There are a number of copper alloys: brass - with zinc, bronze - with tin and other elements, cupronickel - with nickel, babbits - with lead and others.

Chemical properties

Does not change in air in the absence of moisture and carbon dioxide. It is a weak reducing agent, does not react with water, dilute hydrochloric acid. It is transferred into solution with non-oxidizing acids or ammonia hydrate in the presence of oxygen, potassium cyanide. Oxidized by concentrated sulfuric and nitric acids, aqua regia, oxygen, halogens, chalcogens, non-metal oxides. Reacts on heating with hydrogen halides.

Modern mining methods

90% of primary copper is obtained by the pyrometallurgical method, 10% - by the hydrometallurgical method. The hydrometallurgical method is the production of copper by leaching it with a weak solution of sulfuric acid and then separating metallic copper from the solution. The pyrometallurgical method consists of several stages: enrichment, roasting, melting to matte, blowing in the converter, refining.
For the enrichment of copper ores, the flotation method is used (based on the use of different wettability of copper-containing particles and waste rock), which makes it possible to obtain a copper concentrate containing from 10 to 35% copper.
Copper ores and concentrates with a high sulfur content are subjected to oxidative roasting. In the process of heating the concentrate or ore to 700-800 °C in the presence of atmospheric oxygen, sulfides are oxidized and the sulfur content is reduced by almost half of the original. Only poor concentrates (with a copper content of 8 to 25%) are fired, while rich concentrates (from 25 to 35% copper) are melted without firing.
After roasting, the ore and copper concentrate are smelted into matte, which is an alloy containing copper and iron sulfides. The matte contains from 30 to 50% copper, 20-40% iron, 22-25% sulfur, in addition, the matte contains impurities of nickel, zinc, lead, gold, silver. Most often, melting is carried out in flame reverberatory furnaces. The temperature in the melting zone is 1450 °C.
In order to oxidize sulfides and iron, the resulting copper matte is subjected to blowing with compressed air in horizontal converters with side blast. The resulting oxides are converted into slag. The temperature in the converter is 1200-1300 °C. It is interesting that the heat in the converter is released due to the occurrence of chemical reactions, without fuel supply. Thus, blister copper is obtained in the converter, containing 98.4 - 99.4% copper, 0.01 - 0.04% iron, 0.02 - 0.1% sulfur and a small amount of nickel, tin, antimony, silver, gold. This copper is poured into a ladle and poured into steel molds or on a pouring machine.
Further, to remove harmful impurities, blister copper is refined (fire and then electrolytic refining is carried out). The essence of fire refining of blister copper is the oxidation of impurities, their removal with gases and their conversion into slag. After fire refining, copper is obtained with a purity of 99.0 - 99.7%. It is poured into molds and ingots are obtained for further smelting of alloys (bronze and brass) or ingots for electrolytic refining.
Electrolytic refining is carried out to obtain pure copper (99.95%). Electrolysis is carried out in baths, where the anode is made of fire-refined copper, and the cathode is made of thin sheets of pure copper. The electrolyte is an aqueous solution. When a direct current is passed, the anode dissolves, copper goes into solution, and, purified from impurities, is deposited on the cathodes. Impurities settle to the bottom of the bath in the form of slag, which is processed to extract valuable metals. The cathodes are unloaded in 5-12 days, when their mass reaches 60 to 90 kg. They are thoroughly washed and then melted down in electric furnaces.

The ancient Greeks called this element chalkos, in Latin it is called cuprum (Cu) or aes, and medieval alchemists called this chemical element none other than Mars or Venus. Mankind has long been acquainted with copper due to the fact that in natural conditions it could be found in the form of nuggets, often of very impressive size.

The easy reducibility of carbonates and oxides of this element contributed to the fact that, according to many researchers, our ancient ancestors learned to restore it from ore before all other metals.

At first, copper rocks were simply heated over an open fire, and then cooled sharply. This led to their cracking, which made it possible to carry out the restoration of the metal.

Having mastered such a simple technology, a person began to gradually develop it. People learned to blow air into fires with the help of bellows and pipes, then they thought of installing walls around the fire. In the end, the first shaft furnace was also constructed.

Numerous archaeological excavations have made it possible to establish a unique fact - the simplest copper products already existed in the 10th millennium BC! And copper began to be mined and used more actively after 8-10 thousand years. Since then, mankind has been using this chemical element, unique in many respects (density, specific gravity, magnetic characteristics, and so on), for its needs.

Today, copper nuggets are extremely rare. Copper is mined from various, among which the following can be distinguished:

• bornite (it contains up to 65% cuprum);
• copper luster (aka chalcosine) with a copper content of up to 80%;
• copper pyrite (in other words, chalcoperite), containing about 30% of the chemical element of interest to us;
• covelline (it contains up to 64% Cu).

Cuprum is also mined from malachite, cuprite, other oxide ores, and nearly 20 minerals containing it in various quantities.

2

In a simple form, the described element is a pinkish-red metal, characterized by high plasticity. Natural cuprum includes two nuclides with a stable structure.

The radius of a positively charged copper ion has the following values:

• with a coordination index of 6 - up to 0.091 nm;
• with an indicator of 2 - up to 0.060 nm.

A neutral atom of an element is characterized by a radius of 0.128 nm and an electron affinity of 1.8 eV. With sequential ionization, the atom has values ​​from 7.726 to 82.7 eV.

Cuprum is a transition metal, so it has variable oxidation states and a low electronegativity (1.9 Pauling units). (coefficient) is 394 W / (m * K) at a temperature range from 20 to 100 ° C. The electrical conductivity of copper (specific index) is a maximum of 58, a minimum of 55.5 MS/m. Only silver is characterized by a higher value, the electrical conductivity of other metals, including aluminum, is lower.

Copper cannot displace hydrogen from acids and water, since it is to the right of hydrogen in the standard potential series. The described metal is characterized by a face-centered cubic lattice with a value of 0.36150 nm. Copper boils at a temperature of 2657 degrees, melts at a temperature of just over 1083 degrees, and its density is 8.92 grams / cubic centimeter (for comparison, the density of aluminum is 2.7).

Other mechanical properties of copper and important physical indicators:

• pressure at 1628 ° C - 1 mm Hg. Art.;
• thermal value of expansion (linear) - 0.00000017 units;
• in tension, a tensile strength of 22 kgf / mm2 is achieved;
• copper hardness - 35 kgf / mm2 (Brinell scale);
• specific gravity - 8.94 g / cm3;
• modulus of elasticity - 132000 MN/m2;
• elongation (relative) - 60%.

The magnetic properties of copper are somewhat unique. The element is completely diamagnetic, its magnetic atomic susceptibility index is only 0.00000527 units. The magnetic characteristics of copper (however, like all its physical parameters - weight, density, etc.) determine the demand for the element for the manufacture of electrical products. Aluminum has approximately the same characteristics, therefore, with the described metal, they make up a "sweet couple" used for the production of conductive parts, wires, cables.

It is almost impossible to change many mechanical properties of copper (the same magnetic properties, for example), but the tensile strength of the element in question can be improved by hardening. In this case, it will approximately double (up to 420–450 MN/m2).

3

Cuprum in the Mendeleev system is included in the group of noble metals (IB), it is in the fourth period, has serial number 29, and has a tendency to complex formation. The chemical characteristics of copper are no less important than its magnetic, mechanical and physical characteristics, whether it be its weight, density or other value. Therefore, we will talk about them in detail.

The chemical activity of cuprum is low. Copper in a dry atmosphere changes slightly (one might even say that it almost does not change). But with an increase in humidity and the presence of carbon dioxide in the environment, a film of a greenish tint usually forms on its surface. It contains CuCO3 and Cu(OH)2, as well as various copper sulfide compounds. The latter are formed due to the fact that there is almost always a certain amount of hydrogen sulfide and sulfur dioxide in the air. This greenish film is called patina. It protects the metal from destruction.

If copper is heated in air, the processes of oxidation of its surface will begin. At temperatures from 375 to 1100 degrees as a result of oxidation, a two-layer scale is formed, and at temperatures up to 375 degrees - copper oxide. At ordinary temperatures, however, a combination of Cu with wet chlorine is usually observed (the result of such a reaction is the appearance of chloride).

With other elements of the halogen group, copper also interacts quite easily. In sulfur vapor, it ignites; it also has a high level of affinity for selenium. But Cu does not combine with carbon, nitrogen and hydrogen even at elevated temperatures. Upon contact of copper oxide with dilute sulfuric acid, sulfate and pure copper are obtained, with hydroiodic and hydrobromic acid, copper iodide and copper bromide, respectively.

If the oxide is combined with one or another alkali, the result of a chemical reaction will be the appearance of cuprate. But the most famous reducing agents (carbon monoxide, ammonia, methane and others) are able to restore cuprum to a free state.

Of practical interest is the ability of this metal to react with iron salts (in the form of a solution). In this case, the reduction of iron and the transition of Cu into solution are fixed. This reaction is used to remove a sprayed layer of copper from decorative items.

In mono- and divalent forms, copper is able to create complex compounds with a high stability index. Such compounds include ammonia mixtures (they are of interest to industrial enterprises) and double salts.

4

The main scope of aluminum and copper is known, perhaps, to everyone. They make a variety of cables, including power ones. This is facilitated by the low resistance of aluminum and cuprum, their special magnetic capabilities. In the windings of electric drives and in transformers (power), copper wires are widely used, which are characterized by a unique purity of copper, which is the feedstock for their production. If only 0.02 percent of aluminum is added to such a pure raw material, the electrical conductivity of the product will decrease by 8–10 percent.

Cu, having a high density and strength, as well as low weight, can be easily machined. This allows us to produce excellent copper pipes that demonstrate their high performance in gas, heating, and water supply systems. In many European countries, it is copper pipes that are used in the overwhelming majority of cases for arranging internal engineering networks of residential and administrative buildings.

We have said a lot about the electrical conductivity of aluminum and copper. Let's not forget about the excellent thermal conductivity of the latter. This characteristic makes it possible to use copper in the following designs:

• in heat pipes;
• in coolers of personal computers;
• in heating systems and air cooling systems;
• in heat exchangers and many other devices that remove heat.

The density and light weight of copper materials and alloys have led to their widespread use in architecture.

5

It is clear that the density of copper, its weight and all kinds of chemical and magnetic indicators, by and large, are of little interest to the average person. But the healing properties of copper want to know many.

Ancient Indians used copper to treat the organs of vision and various skin ailments. The ancient Greeks healed ulcers, severe swelling, bruises and bruises, as well as more serious diseases (inflammation of the tonsils, congenital and acquired deafness) with copper plates. And in the East, red copper powder dissolved in water was used to restore broken bones of the legs and arms.

The healing properties of copper were well known to the Russians. Our ancestors used this unique metal to cure cholera, epilepsy, polyarthritis and radiculitis. Currently, copper plates are usually used for treatment, which are applied to special points on the human body. The healing properties of copper with such therapy are manifested in the following:

• the protective potential of the human body increases;
• infectious diseases are not terrible for those who are treated with copper;
• there is a decrease in pain and removal of inflammation.