Melting point of mercury. Element of mercury

All the chemical elements of the periodic table are conventionally separated by the diagonal B-At into metals and non-metals. The latter are in the minority, they are located higher and to the right of the border. Metals are in a clear quantitative advantage, of the known 118 elements more than 80.

All of them have similar physical properties, are combined by an aggregate state. However, there is an exception - an element of mercury. About it and talk more.

Mercury: position in the periodic table

This element occupies its cell in the table at number 80. It is located in the second group, the subgroup, the sixth major period. It has an atomic mass equal to 200.59. It exists in the form of seven stable isotopes: 196, 198, 199, 200, 201, 202, 204.

Refers to the elements of the d-family, but not transient, since the last valence electrons fill the s-orbital. Mercury is a subgroup of zinc metals, together with cadmium and copernicium.

General characteristic of the element

The chemical elements of Mendeleyev's table have a strictly ordered arrangement, and each has its electronic configuration of the atom, which speaks of its properties. Mercury is no exception. The structure of its outer and pre-external electron shell is as follows: 5s ² 5p ⁶ 5d ¹⁰ 6s ² .

Possible oxidation states: +1, +2. Oxide and hydroxide of mercury are weakly basic, sometimes amphoteric in nature compounds. The chemical symbol of element number 80 is Hg, the Latin pronunciation is "hydrargyrum". The Russian name comes from the Old Slavonic language, in which it was translated as "rolling". In other peoples, pronunciation and name are different. Often the element itself and its simple and complex substances are called mercury, mercury. This name comes from ancient times, when they compared Hg (element) with silver, gave it a second meaning after gold. The sun is a symbol of the aurum Au, Mercury is the symbol of the hydrargyrum Hg.

The ancient peoples believed that there are seven basic metals, among them mercury. A group of them was reflected in celestial bodies. That is, gold was associated with the Sun, iron - with Mars, mercury - with Mercury and so on.

History of the discovery

Mercury was known about 1500 years before our era. Even then it was described as "liquid silver", a mobile, unusual and mysterious metal. To learn it, too, learned in antiquity.

Of course, it was impossible to study its properties, because chemistry was not yet formed as such. Mercury enveloped in a veil of mystery and magic, was considered an unusual substance close to silver and capable of turning into gold if you make it solid. However, there was no way to get pure mercury in a solid aggregate state, and alchemical research was not successful.

The main countries where from the very earliest times mercury was used and extracted was:

• China;
• Mesopotamia;
• India;
• Egypt.

However, it was in the pure form that this metal was obtained only in the 18th century, this was done by the Swedish chemist Brandt. At the same time, neither nor to them, nor have they been shown evidence of the metallic nature of the substance. This question was clarified by MV Lomonosov and Brown. It was these scientists who first managed to freeze mercury and thus confirm that it is characterized by all the properties of metals - gloss, electrical conductivity, ductility and ductility, a metal crystal lattice.

To date, a variety of mercury compounds have been obtained, it is used in various fields of technical production.

Substance mercury

As a simple substance is a liquid (under normal conditions) silvery-white, mobile, easily volatile. A typical example where liquid mercury is used in its pure form is thermometers, thermometers for measuring temperature.

If you transfer mercury to a solid state, it will be a translucent crystal that does not have an odor. The vapors of this substance are colorless, very poisonous.

Physical properties

According to its physical properties, this metal is the only representative, which under ordinary conditions can exist as a liquid. For all other properties, it completely fits the general characteristics of the rest of the category.

The main properties are as follows.

1. Aggregate state: usual conditions - liquid, solid crystals - not higher than 352 ^о С, couples - over 79 K.
2. It dissolves in benzene, dioxane, crystals in water. It has the ability not to wet the glass.
3. It has diamagnetic properties.
4. Heat conductive.

Melting of mercury occurs at a negative temperature of -38.83 ^o C. Therefore, this substance belongs to the group of explosive when heated. The internal energy reserve of the connection increases by several times.

Boiling of mercury begins at a temperature of 356.73 ^o C. At this point, it begins to transfer to the vapor state, which is completely invisible to the eye molecules connected by a covalent nonpolar bond.

The melting point of mercury shows that the properties of this metal are clearly unusual. This substance begins to evaporate, passing into invisible molecules of the gaseous state, even at normal room temperature, which makes it particularly dangerous for human and animal health.

Chemical properties

The following groups of compounds based on mercury are known in different degrees of oxidation:

• Sulfates, sulfides;
• Chlorides;
• Nitrates;
• Hydroxides;
• Oxides;
• Complex compounds;
• Organometallic substances;
• Intermetallic;
• Alloys with other metals - amalgams.

The melting point of mercury allows it to form both liquid and solid amalgams. In such alloys, metals lose their activity, becoming more inert.

The reaction of mercury with oxygen is possible only at a sufficiently high temperature, in spite of the strong oxidizing ability of the nonmetal. Under conditions above 380 ° C, as a result of this synthesis, a metal oxide with a degree of oxidation of the latter +2 is formed.

With acids, alkalis, non-metals in free form, the metal does not enter into a chemical interaction, remaining in the liquid state.

With halogens reacts slowly enough and only in the cold, which confirms the melting point of mercury. A good oxidizer for it is potassium permanganate.

Being in nature

Contained in the earth's crust, the oceans, ores and minerals. If we talk about the total percentage of mercury in the earth's interior, then this is approximately 0.000001%. In general, we can say that this element is scattered. The main minerals and ores that make up this metal are the following:

• cinnabar;
• quartz;
• chalcedony;
• mica;
• Carbonates;
• Lead-zinc ores.

In nature, mercury continually circulates and takes part in the exchange processes of all shells of the Earth.

Getting mercury

The main way of obtaining is the processing of mineral cinnabar. Also possible metallurgical method with the help of reducing agents. When the first method is used, the mineral undergoes severe firing in oxygen. As a result, metal vapors are formed. Since the melting point of mercury is very low, and boiling, on the other hand, is high, the collection and condensation of vapors do not cause difficulties when firing. This method of treating mercury sulfide was used in antiquity to produce the metal in pure form.

The second method is based on the extraction of mercury from the sulphide by the use of a strong reducing agent. Such as iron. The product is collected in the same way as in the previous case.

Biological impact on living organisms

The temperature of the mercury needs to be low enough to pass into the vapor state. This process starts already at 25 ° C, that is, at normal room temperature. In this case, the presence of living organisms in the room becomes hazardous to health.

So, the metal is able to penetrate into the creatures through:

• Skin integument, undamaged, completely intact;
• Mucous membranes;
• Airways;
• Digestive organs.

Once inside, mercury vapor is included in the total bloodstream, and then enters the synthesis of protein and other molecules, forming compounds with them. This is how accumulation of harmful metal in the liver and bones occurs. From storage sites, the metal can again be included in metabolic processes, syntheses and decays, causing a slow intoxication of the organism, accompanied by the most severe consequences.

It is removed from the bodies quite slowly and under the influence of catalysts, adsorbents. For example, milk. The main liquids through which the metal is discharged into the environment:

• saliva;
• bile;
• urine;
• Products of the gastrointestinal tract.

There are two main forms of poisoning with this substance: acute and chronic. Each has its own characteristics and manifestations.

Symptoms and treatment

The acute form is typical for cases when a mercury spill occurs in production, that is, when a huge release of a substance into the atmosphere occurs at a time. In such situations, unprotected people have a sharp deterioration in their well-being, that is, poisoning. Symptoms are as follows:

1. Inflammation of the respiratory system, lungs, mucous membranes of the mouth and throat.
2. The body temperature rises.
3. Ulcers form on the gums, they bleed, swell and become extremely sensitive. Sometimes a mercury rim is formed.
4. There is atrophy of the liver and kidneys.
5. Chills, nausea and vomiting, dizziness.
6. The nervous system suffers very badly - speech and coordination of movements are disturbed, a tremor of extremities is observed.
7. Poisoning is accompanied by headaches and diarrhea with blood inclusions.

If, however, mercury vapor damage occurs gradually, the disease will become chronic. In this case, the manifestations will not be so sharp, however, the deterioration of well-being will accumulate daily, taking on ever larger scale.

1. Tremor of extremities.
2. Diseases of the mouth (gingivitis, stomatitis and others).
3. Hypertension and tachycardia.
4. Sweating.
5. Nerve agitation.
6. Headache.
7. In severe cases, serious mental disorders, up to schizophrenia, can be provoked.

All these consequences can occur even because of a small release of mercury into the atmosphere. If you do not demercurize the premises in time, you can seriously damage your health.

Treatment in these cases is usually performed by the following drugs:

• Vitamins;
• Antihistamines;
• Barbiturates;
• "Aminazine".

Using Man

The most common place of use and storage of metallic mercury is thermometers and thermometers. In one such equipment can be up to 3 g of metal. In addition, there are several other areas of human activity in which mercury is used widely:

• Medicine (calomel, merkuzal, promeran, many antiseptics);
• Technical activities - current sources, incandescent lamps, pumps, barometers, detonators and so on;
• Metallurgy - spraying mirrors, decorating with amalgams of gold and silver, obtaining alloys of metals, pure substances;
• chemical industry;
• Agriculture.

At present, due to the receipt of safer and more convenient substances, mercury is practically displaced from medicine.