What is amalgam chemical properties. What is amalgam. New explanatory and derivational dictionary of the Russian language, T.F. Efremova

- (Arabic amalgama, spoiled Greek malagama softening, softening, with Arabic member al). 1) amalgam: the so-called compound (alloy) of mercury with other metals; 2) in a figurative sense, a mixture in general. Dictionary of foreign words included in ... ... Dictionary of foreign words of the Russian language

Cm … Synonym dictionary

- (medieval lat. amalgama alloy) alloy of mercury with other metal. Amalgam is used, for example, in gilding, in the production of mirrors, in non-ferrous metallurgy (amalgamation) ... Big Encyclopedic Dictionary

AMALGAM, a solid or liquid alloy of mercury with other metals. In the past, dentists used amalgams containing copper and zinc for fillings. Most metals dissolve in mercury, with the exception of iron and platinum ... Scientific and technical encyclopedic dictionary

- (footnote), incoherent laughter in general. Wed Hot altercations (between Slavophiles and Westernizers) ... in Odessa, barely, deaf, distant echoes could be heard to that random amalgam of individuals from all countries and tribes of the world, which ... ... Michelson's Big Explanatory Phraseological Dictionary (original spelling)

AMALGAM, s, wives. 1. Liquid, semi-liquid or solid alloy of mercury with other metals (special). 2. transfer. A heterogeneous mixture, a combination of which n. (book). | adj. amalgam, oh, oh (to 1 value). Ozhegov's Explanatory Dictionary. S.I. Ozhegov, N.Yu. Shvedova. 1949 ... ... Ozhegov's Explanatory Dictionary

Female, chem. descent, connection, alloy of other metals with mercury, amalgam. Silver amalgam is found in nature in the form of ore; gold is made to be cut through fire. Amalgam, amalgam, release. Amalgamic gold, silver, deflated ... ... Dahl's Explanatory Dictionary

Metal, a system in which mercury is one of the components. A. are solid or liquid solutions or crystalline chemical. connections. A. is characterized by polymorphic transformations. Geological Dictionary: in 2 volumes. M .: Nedra. Under… … Geological encyclopedia

amalgam- s, w. amalgame m., Amalgam cf. lat. amalgama. 1.chem. Compound (solution or alloy) of metals with mercury. Sl. 18. Mercury combines with gold, silver, tin and lead very easily, and makes a thick, like dough, soft matter, which ... Historical Dictionary of Russian Gallicisms

amalgam- Alloy of metal, including precious, with mercury, which, depending on the ratio of components and melting point, is a homogeneous or heterogeneous system. Note. A homogeneous system can be in the form of a solid intermetallic compound, ... ... Technical translator's guide

Books

• Amalgam, Vladimir Torin. How can an ancient Venetian secret, many centuries later, destroy a KGB resident in London? What connected Stalin and Napoleon? How did Casanova's famous lover escape from prison? Who in the 10th century ...
• Amalgam, Vladimir Torin. How can an ancient Venetian secret, many centuries later, destroy a KGB resident in London? What connected Stalin and Napoleon? How did Casanova's famous lover escape from prison? Who in the 15th century ...

The beautiful word "amalgam" is heard by many, but not everyone can say exactly what it means. Moreover, this concept has quite a lot of meanings.

Translated from Latin, amalgama is simply "alloy", but in Russian this word is more specific and denotes an alloy of one or more metals with mercury. Mercury is liquid at room temperature and can react with silver, tin, etc., resulting in solid materials. Ancient alchemists believed that mercury was endowed with a special mystical power.

Synonyms of the word "amalgam" in the figurative sense of this word - "mixture" - compound, conglomerate, collection, composition. Hence the multiple associations with old books, and the popularity of the term "amalgam" in the names of some modern companies, in particular, those specializing in the translation of foreign texts and films.

Perhaps the most famous meaning of the word "amalgam" is associated with the widely used technology of making mirrors at one time.

Antique mirrors

For the first time, the technology of making a mirror using amalgam - an alloy of mercury and tin - was applied in the 16th century. However, over time, they abandoned it, tk. the reflection of such mirrors gave a pale, moreover, during their manufacture, workers sometimes received severe poisoning with mercury vapor. In the 19th century, instead of mercury, glass began to be coated with a thin layer of silver.

The reflection in the silver mirrors was bright and clear. In modern technologies, in the manufacture of mirrors, aluminum is used, sometimes silver, tin, copper, as well as chemical activators. Above, a reflective layer applied to the glass is covered with protective varnishes or paints.

Dental fillings

Until recently, silver amalgam was widely used in dentistry as one of the most durable filling materials. Now it is being successfully replaced by composite plastics and solid ceramics, however, silver amalgam fillings with the addition of copper are still used for the restoration of large areas of teeth.

The amount of mercury entering the patient's body from the fillings does not exceed the permissible values. But medical personnel, when constantly working with amalgams, must carefully follow safety rules.

In addition, to prevent mercury vapor from absorbing into the walls, the inside of the dental office should be painted with nitro enamel or oil paint, and there should be no wooden furniture in it.

When amalgam fillings are removed, the load on the patient's body increases; therefore, the working field should be as isolated as possible from the oral cavity by applying hermetic materials. It is very important to avoid the discharge of mercury compounds into the sewer system.

Getting into the environment, in particular - into the water course, organic mercury compounds can be transformed into inorganic forms and absorbed by living organisms. Such seafood, when eaten, can cause severe poisoning.

Other areas of application

Compounds with mercury are also used in metallurgy, in gilding and silvering jewelry, used in various devices, and take part in cold welding in microelectronics.

And the very concept of "amalgam", as noted above, is interpreted in a much broader sense - it is used in higher mathematics, literature, in naming to designate various forms of compounds, etc.

General information

"Amalgam" is the professional name for one of the filling materials, the properties of which take advantage of the ability of mercury to dissolve certain metals (See article: Amalgam). "Amalgam" is the most durable filling material that has been used in dentistry for over 100 years. During this period, the composition of the amalgam has undergone many changes. In dentistry, copper and silver amalgam is used. Currently, almost all countries use silver amalgam with a significant addition of copper, the so-called high-copper amalgams.

Amalgam filling

Receiving

It is obtained by the interaction of a metal with mercury (when the metal surface is wetted with mercury) at ordinary temperatures or heating, by electrolytic separation of a metal or a cationic complex on a mercury cathode, or by other methods. Alkali and alkaline earth metals and some other elements form stable compounds with mercury.

Properties

When heating amalgams of copper, silver, gold, etc., mercury is distilled off. Iron does not form amalgams, so mercury can be transported in steel containers.

Application

Amalgam is used in the gilding of metal products, in the production of mirrors. Amalgams of alkali metals and zinc are used in chemistry as reducing agents. Amalgam is used in the electrolytic production of rare metals, the extraction of some metals from ores (see Amalgamation). Amalgam is used for cold welding in microelectronics. Previously, silver amalgam was used in dentistry as a material for dental fillings.

Silver amalgam

Silver amalgam consists of mercury, silver, tin, zinc, etc. Silver gives the amalgam hardness, tin slows down the hardening process, copper increases strength and ensures the adhesion of the filling to the edges of the cavity.

The advantages of silver amalgam are hardness, plasticity, property not to change the color of the tooth (amalgams of the latest generations), it does not break down and does not change in the oral cavity. The disadvantages of amalgam are poor adhesion, high thermal conductivity, shrinkage and the presence of mercury in its composition, which is known to have a toxic effect.

Adverse effects of amalgam

The issue of the adverse effects of mercury has been debated since the beginning of the use of amalgam fillings. It has been established that mercury from the amalgam enters the oral fluid and then into the body. However, the amount of mercury entering the body from fillings (even in the presence of 7-10 fillings) does not exceed the maximum permissible dose. There is a possibility of intoxication of employees of dental offices, which requires careful observance of the norms and requirements of safety rules. If a gold crown is placed in the oral cavity, in which there is a tooth filled with amalgam, the second one will collapse. This must be taken into account when treating.

Amalgams - compounds of metals with mercury, are reliable and durable filling materials. In their composition, they contain silver, copper, tin.

Positive properties of amalgams:

plastic;

solid, chemically resistant;

harden at 37 ° C;

provide the longest life of the fillings, have bactericidal properties.

Negative properties of amalgams:

high thermal conductivity;

significant shrinkage with a lack of mercury;

the ability to corrode gold crowns;

do not match the color of the teeth;

poor adhesion to hard tooth tissues. The amalgams are mixed in a fume hood manually or using an amalgam mixer.

Indications for the use of amalgams:

Cavities 1; 2; 5th grade.

The most widely used amalgams are in pediatric practice. They are produced by the industry in the form of sawdust, tablets, and amalgamated alloys.

Dental amalgam is one of the oldest filling materials. The first mentions of its use date back to 1800. Its popularity throughout the world is due to its ease of use, as well as the reliability of restorations, especially in the lateral areas, and the low cost of components. Despite such a long period of use of amalgam, its alloy remained almost unchanged until the 60s of the XX century. Around 1960, a high copper content amalgam was proposed. Currently, most alloys belong to this group.

Functions of the amalgam alloy components.

Silver provides strength and corrosion resistance and causes expansion when solidified.

Tin causes shrinkage during hardening, decreases strength and corrosion resistance, and increases hardening time.

Zinc in the amalgam production process reduces the oxidation of other metals in the alloy. Amalgams with a zinc content of more than 0.01% are called zinc-containing. For many years, the role of zinc has been debated, recent studies have shown the great durability of zinc-containing amalgam fillings. However, if the cavity is contaminated with moisture or saliva during the placement of the filling, a significant increase in the volume of the filling is observed.

Other metals are added in a volume not exceeding a few percent, and do not radically change the properties of the amalgam.

Amalgam classification

The size and shape of the alloy particles.

Needle, or traditional (ordinary). This alloy powder is obtained by grinding an amalgam alloy ingot on a lathe to obtain sawdust. It is characterized by rigidity during investment.

Spherical - obtained by spraying molten amalgam in an inert gas. Requires less mercury for the curing reaction, i.e. it has better final physical properties. It is characterized by softness during investment, which is not always convenient.

Mixed - obtained by mixing the first two types of powders. Amalgam's "packability" is regulated by changing the proportions of these components.

Low copper amalgam alloys (silver) contain less than 6% copper (CCA). Until 1960, almost all amalgams were of this type.

Amalgam alloys with a high copper content (copper) usually contain 10-30% copper (SSTA-43, Tytin, Contour, Kerr; Septalloy, Septodont). Most modern amalgams have this composition. There are several reasons for this. First, at a high copper content, there is no reaction between tin and mercury, that is, the weakest and most corrosive gamma-2 phase is not formed. Secondly, copper replaces some of the silver in the alloy, which makes amalgam cheaper.

Amalgams can be described as containing gamma-2-phase or not. Amalgams with a low copper content have an Hg - Sn (g2) phase in their composition, which impairs their physical properties.

All amalgams with a high copper content do not contain the γ2 phase a few hours after mixing.

Amalgams with a zinc concentration of more than 0.01% are called zinc-containing ("Dispersalloy", Dentsply). Clinically, these amalgams have high strength, durability and good marginal adhesion. However, contact with the moisture of such an amalgam before it condenses in the oral cavity causes a significant (several hundred micrometers per centimeter) expansion over several days. This is due to the formation of hydrogen in the amalgam structure from moisture in the presence of zinc, which causes a dimensional change. This problem can be avoided by using zinc-free amalgams.

Amalgam properties.

Phases. To obtain dental amalgam, the amalgam alloy is mixed with mercury. During the mixing process, mercury reacts with alloy sawdust and causes a curing reaction. For the convenience of describing these processes, the symbols of the most important compounds of this reaction have been introduced. The gamma phase denotes an alloy of silver and tin Ag3Sn, the gamma-1 phase - the compound of silver and mercury Ag2Hg3, the gamma-2 phase - tin and mercury Sn8Hg. The gamma-2 phase is the weakest and most susceptible to corrosion. In amalgams with a high copper content, when properly mixed, the gamma-2 phase either does not form at all, or is eliminated a few hours after mixing.

Mechanical properties. All amalgams have good mechanical properties. Depending on the shape of the alloy particles and their composition, the compressive strength varies from 390 to 590 MPa, the diametral strength is from 122 to 148 MPa, the modulus of elasticity is from 41 to 56 GPa, and the static deformation is from 0.1 to 2.5%. Spherical amalgams with a high copper content are characterized by the greatest strength both immediately after hardening and after a week.

The thermal expansion coefficient of amalgam is tens of times higher than that of a tooth. This effect should be taken into account when placing metal seals. In this case, a cement gasket and an insulating varnish can reduce the temperature sensitivity.

Amalgam dimensional changes are generally small. Hardening shrinkage is negligible, especially with amalgams with a high copper content. However, a zinc-containing amalgam filling with a low copper content can increase in volume by 400 microns in the first week. This is due to the ingress of moisture into the cavity of the tooth before placing the filling and can cause severe pain and even split teeth.

The strength of the restored chips of old amalgam fillings will be 50% lower than the original ones. Adding a second portion of amalgam to the filling in one visit gives 75% of the strength of a complete filling. In this case, the preparation of the cavity should be carried out according to all the rules of mechanical retention.

Mercury content. Mercury is an essential component of amalgam, its initial content depends on the composition, shape and size of the alloy particles. For the formation of dental amalgam, the surface of the powder particles must be wetted with mercury. Typically, the initial content of mercury, depending on the properties of the powder, ranges from 40 to 53% by weight. Needle amalgams with a low copper content require the most mercury, spherical amalgams with a high mercury content the least. The final content of mercury in amalgams is 37-48% and depends on its initial content and the technique of placing the filling.

Biocompatibility. The biocompatibility of amalgam has been the subject of intense research for decades. It is currently believed that amalgam fillings do not harm the health of patients, except in rare cases of hypersensitivity. However, many researchers reasonably believe that mercury from dental amalgam can pose a threat to the health of dental personnel, patients and the environment. Based on the toxicological effect of mercury on the body, three forms can be considered:

Elemental mercury (liquid or vapor);

Inorganic mercury compounds;

Organic compounds of mercury.

Liquid mercury is relatively poorly absorbed through the skin and mucous membranes. When absorbed, mercury is mainly ionized and easily excreted by the kidneys. The previously widespread practice of squeezing the mercury out of the mixed amalgam by hand did not result in any serious health problems for the operator. Liquid mercury does not pose a health hazard to the patient if its particles are swallowed. In this case, the mercury is released unchanged in the faeces.

Mercury vapors are much more hazardous to health, as they are quickly absorbed into the bloodstream through the lungs, remaining for several minutes in a non-ionized, i.e. lipophilic, form. The latter allows her to penetrate tissue barriers, such as the blood-brain. Thus, mercury can accumulate in tissues. The greatest danger is the accumulation of mercury in the brain and nerve cells. At a high concentration of mercury, nerve conduction is damaged, which leads to disruption of the brain, up to and including death. At lower concentrations, anxiety, tremors, loss of concentration, and impairment of certain functions are noted. There is a real health risk for dental personnel working in areas with a high mercury content. The amount of mercury evaporating from amalgam fillings, even with a large amount in the patient's oral cavity, is significantly lower than the amount that can be harmful to health.

Inorganic mercury compounds presented in dental amalgam have low or very low toxicity. They are poorly absorbed, do not accumulate in body tissues and are well excreted. Some inorganic mercury compounds are used as topical antibacterial agents. Sulfur is commonly used to "control" mercury, since their interaction produces mercury sulphide, which is not hazardous to the environment.

Organic mercury compounds very toxic in low concentrations, but none of these compounds are formed in the oral cavity when dental amalgam is used. A much greater concern is the discharge of mercury compounds with water through sewers into the environment. Once in the water course, organic mercury compounds end up in large bodies of water, where microorganisms convert them into inorganic forms, such as mercury chloride. Then these compounds are absorbed by living organisms. Through the food chain, mercury passes through seafood to humans, causing poisoning.

Corrosion. Corrosion refers to the electrochemical destruction of a metal when interacting with surrounding substances. All amalgams are corrosive. On the one hand, corrosion gradually leads to a deterioration in the mechanical properties of the amalgam, on the other hand, corrosion products fill the micro-gaps between the tooth wall and the filling. Amalgams that do not contain gamma-2 are significantly less corrosive than amalgams with a low copper content. Acceleration of corrosion is facilitated by the presence of various metals and alloys in the oral cavity, especially in close proximity to each other. Contacting the old amalgam with the new one also has the same effect.

Clinical properties. A large number of laboratory and clinical studies confirm the high reliability of amalgam as a filling material.

(French amalgame, - a device for softening impacts) - a metal system, one of the components of which is. One of the oldest materials (known for more than 2000 years), the widespread use of which began in the 19th century. Distinguish amalgam simple, containing, in addition to mercury, one of any metal, and mixed (complex), to-rye contain, in addition to mercury, two or more metals.

Amalgam is produced by electrochemical and chemical methods, as well as by direct interaction of metals and mercury. At room temperature, amalgam is liquid, semi-liquid (suspension) and solid. Liquid amalgams include metals that are readily soluble in mercury (silver, gold, tin, zinc, cadmium, thallium, lead, magnesium and indium), if their concentration does not exceed the solubility limit; to semi-liquid - amalgamation of metals that are poorly soluble in mercury (aluminum, cobalt, iron, titanium, nickel, etc.); to solid - A. metals, readily soluble in mercury, if their concentration exceeds the solubility limit. A. are distinguished by a liquid state in a wide range of t-p, inertness with respect to some aggressive media, good thermophysical properties, and high density.

Some intermetallic with metals have semiconducting and superconducting properties. Amalgamated surfaces protect some metal products, for example. zinc, from the action of sulfuric acid. Liquid amalgams are widely used, on the basis of which amalgam metallurgy of indium, cadmium, thallium, lead and gallium is created.

Amalgam of gold is used for gilding items made of silver, copper, brass and bronze. The possibility of using aluminum as a heat carrier in ferrous metallurgy is being studied. Solid aluminum is used in dentistry (alloy 59-66% Hg, 32-37% Cu, 2-4% Zn), as a solder (alloy 4% Hg, 3% Sn, 93% Pb), in the production of mirrors ( alloy 30% Hg, 70% Sn). The toxicity of mercury somewhat limits the use of amalgam.

Yet one thinga remarkable property of mercury: the ability to dissolve others, forming solid or liquid solutions - amalgams. Some of them, such as silver amalgamsand cadmium, are chemically inert and hard at human body temperature, but soften easily when heated. Of them make dental fillings.Thallium amalgam, which solidifies only at -60 ° C, is used in special designs of low-temperature thermometers.

The ancient mirrors were covered not with a thin layer of silver, as is done now, but with amalgam, which consisted of 70% tin and 30% mercury. In the past, amalgamation was the most important technological process in the extraction of gold from ores. In the 20th century, it could not stand the competition and gave way to a more advanced process - cyanidation. However, the old process is still used today, mainly in the recovery of gold, finely impregnated in ore. Some, in particular, are practically not amenable to amalgamation. This makes it possible to transport liquid metal in containers made of plain steel. (Extra clean ones are transported in containers made of glass, ceramics or plastic.)

In addition to iron and its analogs, they do not amalgamate, and there are almost all of them used for alloying steel. This means that alloy steel is not scary, but, for example, amalgamation is very easy. Sodium amalgam is readily biodegradable. These two circumstances have played and continue to play a very important role in the chlorine industry. Metallic mercury cathodes are used in the production of chlorine and caustic soda by the electrolysis of sodium chloride. To obtain a ton of caustic soda, you need from 125 to400 g element no. 80. Today the chlorine industry is one of the most massive consumers of metallic mercury.

Lit .: Gavze M.N. Interaction of mercury with metals and alloys.

Amalgam article

what is amalgam

1. Mirror cover. Alloy of mercury with other metals
2. This is the thing that is on the other side of the mirror
3. Amalgam (Wed-century lat. Amalgama alloy) liquid or solid alloys of mercury with other metals. Also, amalgam can be a solution of ionic complexes behaving like metals (for example, ammonium).
4. Liquid or solid alloys of mercury with other metals. Also, amalgam can be a solution of ionic complexes behaving like metals (for example, ammonium).
5. AMALGAM is a covering for a mirror
6. AMALGAMA (medieval lat. Amalgama - alloy), an alloy of mercury with another metal. Amalgam is used, for example. , in gilding, in the production of mirrors, in non-ferrous metallurgy (amalgamation).
7. this is what is on the other side of the mirror ...
8. something like mercury
9. Amalgam - definitions on the internet:
   Amalgam is the professional name for one of the filling materials ...
   ru.wikipedia.org/wiki/Amalgam_(Dentistry)

   Amalgam (Wed-century amalgama alloy) liquid or solid alloys of mercury with other ...
   en.wikipedia.org/wiki/Amalgam

   f. chem. descent, connection, alloy of other metals with mercury, amalgam. ..
   voc.metromir.ru/voc_dal/P002.HTM

   sealing material for permanent fillings
   www.zubnoy.spb.ru/slovar.html

   any alloy that contains mercury. In dentistry, amalgam fillings ...
   biotec.ru/index/product/gloss/
   more specifically:
   1. Amalgam (Wed-century lat. Amalgama alloy) liquid or solid alloys of mercury with other metals. They are obtained by the interaction of a metal with mercury (when the metal surface is wetted with mercury) at ordinary temperatures or heating, by electrolytic separation of the metal on a mercury cathode, or by other methods. Alkali and alkaline earth metals and some other elements form stable compounds with mercury. When heating amalgams of copper, silver, gold, etc., mercury is distilled off. Iron does not form amalgams, so mercury can be transported in steel containers. Amalgam is used in the gilding of metal products, in the production of mirrors. Amalgam of alkali metals and zinc is used in chemistry as reducing agents. Amalgam is used in the electrolytic production of rare metals, in the extraction of certain metals from ores.

   2. Amalgam is the professional name for one of the filling materials, the properties of which take advantage of the ability of mercury to dissolve some metals. Amalgam is the most durable filling material that has been used in dentistry for over 100 years. During this period, the composition of the amalgam has undergone many changes. In dentistry, copper and silver amalgam is used. Currently, almost all countries use silver amalgam with a significant addition of copper, the so-called high-copper amalgams.

   Silver amalgam consists of mercury, silver, tin, zinc, etc. Silver gives the amalgam hardness, tin slows down the hardening process, copper increases strength and ensures the adhesion of the filling to the edges of the cavity.

   The advantages of silver amalgam are hardness, plasticity, property not to change the color of the tooth (amalgams of the latest generations), it does not break down and does not change in the oral cavity. The disadvantages of amalgam are poor adhesion, high thermal conductivity, shrinkage and the presence of mercury in its composition, which is known to have a toxic effect.

   The issue of the adverse effects of mercury has been debated since the beginning of the use of amalgam fillings. It has been established that mercury from the amalgam enters the oral fluid and then into the body. However, the amount of mercury entering the body from fillings (even in the presence of 7-10 fillings) does not exceed the maximum permissible dose. There is a possibility of intoxication of employees of dental offices, which requires careful observance of the norms and requirements of safety rules.
   http://ru.wikipedia.org/wiki/Amalgam

10. As far as I know, amalgam is a mirror layer on glass! Other values ​​are also possible.
11. Amalgam, an alloy, one of the components of which is mercury. Depending on the ratio of mercury and other metals, A. can be (at room temperature) liquid, semi-liquid, or solid. The formation of aluminum occurs when the metal is wetted with mercury as a result of the diffusion of mercury into the metal. From liquid and semi-liquid aluminum (excess mercury contains a small amount of metal), mercury is removed by filtration through suede under pressure; solid nitrogen decomposes into its component parts when heated (traces of mercury are removed from the metal during subsequent melting). A. is used in the gilding of metal products, in the manufacture of mirrors, in dentistry, and also as a restorer.
12. a mixture of mercury with silver