Bromine? Presence trace elements in the human body is calculated in very small quantities, because these are substances that are less than 0.015 g in our body. From the mass of an organ or tissue, their content is thousandths of a percent or less (10 -2 to 10 -7%), therefore they are also called trace elements. But, despite such a meager presence, a sufficient amount of these substances is an important condition for the full functioning of all systems and organs. One of these minerals is . About him properties and significance for health will be discussed in this article, the main directions of its use for therapeutic and prophylactic purposes.

Bromine: Discovery Story

interesting history of the discovery of bromine, which remained the last white spot among halogens. In parallel, it was isolated from different substances by two chemists at once: in 1825, a student at Heidelberg University K. Levig when exposed to chlorine on mineral water and French chemist A. Balar, who studied the plants of marshes, - in the reaction of chlorine water with algae ash. However, while Levig was trying to get more of the new substance, Balard had already published an account of his discovery in 1826, gaining worldwide fame due to this. The resulting substance Balar wanted to call the Latin word "murid", which means "brine". However, hydrochloric acid was called muriatic acid, and the salts derived from it were called muriates, and in order to avoid terminological confusion in the scientific community, it was decided to call the discovered mineral bromine, which translates from ancient Greek as “stench”. Bromine does indeed have a suffocating, unpleasant odor. In Russian chemical science during the 19th century, this trace element was designated as vrom, vromid and murid.

Bromine in the optimal natural form and dosage is contained in bee products - such as flower pollen, royal jelly and drone brood, which are part of many natural vitamin and mineral complexes of Parapharm: Leveton P, Elton P, Leveton Forte ”, “Apitonus P”, “Osteomed”, “Osteo-Vit”, “Eromax”, “Memo-Vit” and “Kardioton”. That is why we pay so much attention to each natural substance, talking about its importance and benefits for the health of the body.

Chemical and physical
bromine properties

Story about chemical and physical properties of bromine Let us preliminarily describe its place in Mendeleev's periodic table of chemical elements. In it, it is located under symbolBr (from lat. Bromum) under the 35th number in the 17th group, where are halogens(fluorine, chlorine, bromine, iodine and astatine). These are non-metals and active oxidizers, not presented in nature on their own, but only as part of compounds, since they are highly chemically reactive, combining with almost all simple substances. There are only 2 elements whose simple substances are in liquid form under normal conditions - mercury and bromine, and only one liquid non-metal - bromine, which is a red-brown, fuming brownish vapor, poisonous liquid. Bromine crystallizes only at a temperature of -7.25 °C, and boils at +59 °C. It dissolves in H 2 O (so-called bromine water is obtained), but it is better in organic solvents.

pure bromine. represented by a 2-atomic molecule - Br2, but high chemical activity does not allow it to be in nature in a free state, so it is found in composition of bromides(compounds with metals). In terms of content in the earth's interior and rocks, it occupies the 50th place, so that its natural source is mostly salt lakes and seas; groundwater accompanying oil. It is also present in the air, more - in coastal areas. However, during industrial leakage, bromine vapors have a poisoning and suffocating effect on people.

The properties of bromine allow it to be widely used for the production of fuel additives, pesticides in agriculture, substances that slow down combustion, a light-sensitive agent of silver bromide in photography, and medicines. Working with this trace element requires extreme caution and safety precautions. Gloves, overalls and a gas mask are your best allies when dealing with this substance.

Bromine value
for the body human

pure bromine- highly toxic substance! Only 3 grams elemental bromine, if ingested, cause poisoning, and 35 grams are lethal. Contact with liquid bromine fraught with painful, poorly healing burns. 0.001% bromine in the air causes coughing, suffocation, dizziness, nosebleeds, and exceeding this figure threatens with respiratory spasms and death. However, despite the toxicity, the value of bromine for the body It's hard to downplay a person. He is a microelement contained in our organs and tissues: brain, blood, liver and kidneys, thyroid gland, muscle tissues and bones ... We need it in small quantities!

Bromine has an effect to the central nervous system. Accumulating in the cerebral cortex, it regulates the activity of neurons, being responsible for the balance between the reactions of excitation and inhibition. If necessary, it enhances inhibition by means of membrane enzymes, which is the reason for its calming effect.

This trace element is also important for the endocrine system., as it acts as a kind of alternative to iodine and reduces the need for iodine in the thyroid gland, preventing its growth - the occurrence of endemic goiter.

The role of bromine in the work of the gastrointestinal tract due to its activating action on digestive enzymes:

• pepsin (necessary for the breakdown of proteins);
• amylase (breaks down carbohydrates);
• lipase (dissolves and sorts fats during digestion).

Question about the influence of bromine on male sexual activity shrouded in myths. In particular, about the fact that previously prisoners in prisons, patients in psychiatric departments of hospitals and soldiers in the army were added this mineral to food in order to weaken erectile function. For a long time it was believed that bromine, providing a general soothing effect on the body, and oppresses the sexual sphere. However, recent studies have shown quite the opposite effect of taking bromide preparations contributing to the stabilization of the reproductive system in men, increase in seminal fluid and the number of sperm in it.

Bromine is excreted from the body with urine and perspiration. So its intake from the outside through food (and, if necessary, in pharmacological preparations) is necessary. However, its elimination is a lengthy process, so it is possible to increase its concentration in organs and tissues, which is very dangerous for health.

How does lack of bromine
on human health?

Bromine deficiency can cause a number of serious functional disorders. In childhood and adolescence, its deficiency can lead to growth retardation, and for adults it is fraught with a decrease in life expectancy. Problems with falling asleep, neurasthenic and hysterical manifestations, anemia caused by a drop in hemoglobin levels, an increased risk of spontaneous miscarriage in pregnant women, weakening of sexual functions, digestive problems due to a decrease in acidity - all this may be due to a lack of this mineral. The reasons for this condition are metabolic abnormalities or diuretic abuse means to promote removal of bromine from the body. Diagnose lack of bromine and a specialist must prescribe treatment, and self-medication without consulting a doctor in this case is categorically not recommended.

Bromine overdose

No less dangerous bromine overdose arising solely in connection with the use of pharmacological drugs. Its characteristic symptoms will be allergic skin rashes, inflammatory manifestations on the skin, disturbances in the gastrointestinal tract, depression and loss of strength, sleep problems, lethargy, bronchitis and rhinitis as a reaction to the toxic effect of bromine. The nervous system, organs of perception (vision and hearing) suffer, mental processes, cognitive (related to perception) functions worsen.

An excess of bromine can be fatal, so if you suspect an overdose, you should immediately stop using bromine-containing medications and consult a doctor to stop them or adjust the dose.

Taking bromine preparations in
therapeutic and prophylactic purposes

Study of bromide exposure on human health and their introduction into medical practice began almost immediately after bromine discoveries– in the 19th century, so taking bromine preparations- a proven tool in clinical medicine.

Russian physiologist I. P. Pavlov made a significant contribution to the study of the influence bromine-containing compounds to nervous activity. His experiments on dogs proved effective. bromine for neurosis, and appointed bromide doses should be correlated with the type of higher nervous activity (with a strong type, higher doses are required).

Bromides as sedatives are used for neuropsychiatric disorders, insomnia, increased excitability, hysteria and neurasthenia, convulsions, but for the treatment of epilepsy almost ceased to be used. Doctors today are generally wary prescribe bromides due to slow excretion from the body and the risk of developing bromism - chronic bromine intoxication. Such an indication for appointment remains in force. bromine-containing drugs, as a violation of coherence between the cerebral cortex and organs, systems, which often occurs with gastric and duodenal ulcers, at an early stage in the development of hypertension.

Among the common preparations containing bromine, - potassium bromide, sodium bromide, "Adonis-bromine", "Bromcamphor" and others, both oral in the form of powders and solutions, and intravenous. Sodium bromide is applicable for electrophoresis - with painful inflammatory processes, with herpes zoster. Bromide dosage involves taking 0.1-1 gram three times a day.

Daily requirement for bromine

To increase the acidity of gastric juice and activation of sexual function in men, the prevention of nervous disorders, doctors recommend taking 3–8 mg. This is daily requirement for bromine for a healthy person. Many dietary supplements include this trace element along with other minerals. On average, 1 mg enters our body with food.

Bromine content
in products food

Knowing what it's like bromine content in products nutrition, you can increase its intake without the use of pharmacological drugs. This trace element accumulates in many plants, taking it from the depths and binding it into organic non-toxic compounds and salts.

They are especially rich in:

• peas,
• beans,
• lentils,
• various nuts and
• grain crops (barley, wheat, etc.).

From sea water they take it into their composition

• kelp and other algae,
• sea ​​fish.

From rock salt we can also get some bromine. It is also found in dairy products, pasta and bread products made from durum wheat.

- an element of the main subgroup of the seventh group of the fourth period of the periodic system of chemical elements of D. I. Mendeleev, atomic number 35. It is denoted by the symbol Br (lat. Bromum). Reactive non-metal, belongs to the group of halogens. The simple substance bromine (CAS number: 7726-95-6) under normal conditions is a heavy red-brown liquid with a strong unpleasant odor. The bromine molecule is diatomic (formula Br2).

Story

Bromine was discovered in 1826 by A. J. Balar, a young college teacher in the city of Montpellier. The discovery of Balar made his name known to the whole world. From one popular book to another, the assertion wanders that, distressed by the fact that the unknown Antoine Balard was ahead of Justus Liebig himself in the discovery of bromine, Liebig exclaimed that, they say, it was not Balar who discovered bromine, but bromine discovered Balar. However, this is not true, or, more precisely, not entirely true. There was a phrase, but it did not belong to J. Liebig, but to Charles Gerard, who really wanted Auguste Laurent to take the chair of chemistry at the Sorbonne, and not A. Balard, who was elected to the post of professor.

origin of name

The name of the element is βρῶμος — stench.

Receipt

Bromine is obtained chemically from brine brine -:

Physical properties

Under normal conditions, bromine is a red-brown liquid with a sharp unpleasant odor, poisonous, and burns on contact with the skin. Density at 0 ° C - 3.19 g / cm³. The melting point (solidification) of bromine is -7.2 ° C, the boiling point is 58.8 ° C, when boiling, bromine turns from a liquid into a brown-brown vapor, irritating the respiratory tract when inhaled. The standard electrode potential Br² / Br - in an aqueous solution is +1.065 V.

Ordinary bromine consists of the isotopes 79 Br (50.56%) and 81 Br (49.44%). Artificially obtained radioactive isotopes.

Chemical properties

It exists in free form in the form of diatomic molecules Br 2 . A noticeable dissociation of molecules into atoms is observed at a temperature of 800 °C and rapidly increases with a further increase in temperature. The diameter of the Br 2 molecule is 0.323 nm, the internuclear distance in this molecule is 0.228 nm.

Bromine is slightly, but better than other halogens, soluble in water (3.58 g in 100 g of water at 20 ° C), the solution is called bromine water. In bromine water, a reaction proceeds with the formation of hydrobromic and unstable hypobromous acids:

Br 2 + H 2 O → HBr + HBrO.

With most organic solvents, bromine is miscible in all respects, and bromination of organic solvent molecules often occurs.

Bromine is intermediate in chemical activity between chlorine and iodine. When bromine reacts with iodide solutions, free iodine is released:

Br 2 + 2KI → I 2 ↓ + 2KBr.

On the contrary, under the action of chlorine on bromides in aqueous solutions, free bromine is released:

When bromine reacts with sulfur, S 2 Br 2 is formed; when bromine reacts with phosphorus, PBr 3 and PBr 5 are formed. Bromine also reacts with non-metals selenium and tellurium.

The reaction of bromine with hydrogen proceeds when heated and leads to the formation of hydrogen bromide HBr. A solution of HBr in water is hydrobromic acid, similar in strength to hydrochloric acid HCl. Salts of hydrobromic acid - bromides (NaBr, MgBr 2, AlBr 3, etc.). A qualitative reaction to the presence of bromide ions in solution is the formation of a light yellow precipitate of silver bromide AgBr, which is practically insoluble in water, with Ag + ions.

Bromine does not directly react with oxygen and nitrogen. Bromine forms a large number of different compounds with other halogens. For example, bromine forms unstable BrF 3 and BrF 5 with fluorine, and IBr with iodine. When interacting with many metals, bromine forms bromides, for example, AlBr 3, CuBr 2, MgBr 2, etc. Tantalum and platinum are resistant to the action of bromine, to a lesser extent - silver, titanium and lead.

Bromine is a strong oxidizing agent, it oxidizes the sulfite ion to sulfate, the nitrite ion to nitrate, etc.

When interacting with organic compounds containing a double bond, bromine is added, giving the corresponding dibromo derivatives:

C 2 H 4 + Br 2 → C 2 H 4 Br 2.

Bromine also joins organic molecules, which contain a triple bond. The discoloration of bromine water when a gas is passed through it or a liquid is added to it indicates that an unsaturated compound is present in the gas or liquid.

When heated in the presence of a catalyst, bromine reacts with benzene to form bromobenzene C 6 H 5 Br (substitution reaction).

When bromine interacts with alkali solutions and with solutions of sodium or potassium carbonates, the corresponding bromides and bromates are formed, for example:

3Br 2 + 3Na 2 CO 3 → 5NaBr + NaBrO 3 + 3CO 2.

Brominated acids

In addition to the oxygen-free hydrobromic acid HBr, bromine forms a number of oxygen acids: bromine HBrO 4, bromine HBrO 3, bromine HBrO 2, bromine HBrO.

Application

In chemistry

Bromine-based substances are widely used in basic organic synthesis.

In engineering

- Silver bromide AgBr is used in photography as a photosensitive substance.
- Used to create flame retardants - additives that give fire resistance to plastics, wood, textile materials.
- Bromine pentafluoride is sometimes used as a very powerful propellant oxidizer.
- 1,2-dibromoethane is currently used as an antiknock additive in motor fuel, instead of tetraethyl lead.
— Bromide solutions are used in oil production.

In medicine

In medicine, sodium bromide and potassium bromide are used as sedatives.

In the production of weapons

Since the First World War, bromine has been used to produce chemical warfare agents.

Physiological action

Already at a concentration of bromine in the air at a concentration of about 0.001% (by volume), irritation of the mucous membranes, dizziness, and at higher concentrations - spasms of the respiratory tract, suffocation are observed. MPC of bromine vapor is 0.5 mg/m³. When ingested, the toxic dose is 3 g, the lethal dose is from 35 g. In case of poisoning with bromine vapor, the victim must be immediately removed to fresh air; to restore breathing, you can use a swab moistened with ammonia for a short time, periodically bringing it to the victim's nose for a short time. Further treatment should be carried out under medical supervision. Liquid bromine on contact with the skin causes painful burns.

Features of work

When working with bromine, protective clothing, a gas mask, and special gloves should be used. Due to the high reactivity and toxicity of both bromine vapor and liquid bromine, it should be stored in a glass, tightly sealed thick-walled container. Vials with bromine are placed in containers with sand, which protects the flasks from destruction when shaken. Due to the high density of bromine, bottles with it should never be taken only by the throat (the throat may come off, and then the bromine will end up on the floor).

To neutralize the spilled bromine, the surface with it must be filled with a solution of sodium sulfite Na 2 SO 3

Myths and legends

There is a widespread legend that in the army they allegedly add bromine to food to reduce sexual desire. This myth has no basis - the desire is successfully reduced by physical activity, and the supplements actually added to food most often turn out to be ascorbic acid to prevent beriberi. In addition, bromine preparations are salty in taste and do not affect either attraction or potency. They have a sedative and sedative effect.

Red-brown liquid, with a sharp specific odor, poorly soluble in water, but soluble in benzene, chloroform, carbon disulfide and other organic solvents. Such an answer can be given to the question: "What is bromine?" The compound belongs to the group of the most active non-metals, reacting with many simple substances. It is highly toxic: inhalation of its vapors irritates the respiratory tract, and contact with the skin causes severe burns that do not heal for a long time. In our article, we will study its physical properties, as well as consider the chemical reactions characteristic of bromine.

The main subgroup of the seventh group is the position of the element in the periodic table of chemical elements. The last energy layer of an atom contains two s-electrons and five p-electrons. Like all halogens, bromine has a significant electron affinity. This means that it easily attracts negative particles of other chemical elements into its electron shell, becoming an anion. The molecular formula of bromine is Br 2 . Atoms are connected to each other with the help of a joint pair of electrons, this type of bond is called covalent. It is also non-polar, located at the same distance from the nuclei of atoms. Due to the rather large radius of the atom - 1.14A °, the oxidizing properties of the element, its electronegativity and non-metallic properties become less than those of fluorine and chlorine. The boiling point, on the contrary, rises and is 59.2 ° C, the relative molecular weight of bromine is 180. In the free state, due to the high activity, the element as a simple substance does not occur. In nature, it can be found in a bound state in the form of salts of sodium, magnesium, potassium, their content is especially high in sea water. Some types of brown and red algae: sargassum, fucus, batrachospermum, contain a large amount of bromine and iodine.

Reactions with simple substances

The element is characterized by interaction with many non-metals: sulfur, phosphorus, hydrogen:

Br 2 + H 2 \u003d 2HBr

However, bromine does not directly react with nitrogen, carbon and oxygen. Most metals are easily oxidized by bromine. Only some of them are passive to the action of halogen, for example, lead, silver and platinum. Reactions with bromine of more active halogens, such as fluorine and chlorine, are fast:

Br 2 +3 F 2 \u003d 2 BrF 3

In the last reaction, the oxidation state of the element is +3, it acts as a reducing agent. In industry, bromine is produced by the oxidation of hydrogen bromide with a stronger halogen, such as chlorine. The main sources of raw materials for obtaining the compound are underground drilling waters, as well as a highly concentrated solution of salt lakes. Halogen can interact with complex substances from the class of medium salts. So, under the action of bromine water, which has a red-brown color, on a solution of sodium sulfite, we observe a discoloration of the solution. This is due to the oxidation of the middle salt, sulfite, to sodium sulfate by bromine. The halogen itself is reduced, turning into the form of hydrogen bromide, which has no color.

Interaction with organic compounds

Br 2 molecules are capable of interacting not only with simple but also with complex substances. For example, the substitution reaction takes place between the aromatic hydrocarbon benzene and bromine when heated, in the presence of a catalyst - ferric bromide. It ends with the formation of a colorless compound, insoluble in water - bromobenzene:

C 6 H 6 + Br 2 \u003d C 6 H 5 Br + HBr

The simple substance bromine dissolved in water is used as an indicator to determine the presence of unsaturated bonds between carbon atoms in a molecule of organic substances. Such a qualitative reaction is found in the molecules of alkenes or alkynes, pi bonds, on which the main chemical reactions of these hydrocarbons depend. The compound enters into substitution reactions with saturated hydrocarbons, while forming derivatives of methane, ethane and other alkanes. A well-known reaction is the addition of bromine particles, the formula of which is Br2, to unsaturated substances with one or two double or triple bonds in molecules, for example, to such as ethene, acetylene or butadiene.

CH 2 \u003d CH 2 + Br 2 \u003d CH 2 Br - CH 2 Br

With these hydrocarbons, not only a simple substance can react, but also its hydrogen compound - HBr.

Features of the interaction of halogen with phenol

An organic substance consisting of a benzene ring associated with a hydroxyl group is phenol. In its molecule, the mutual influence of groups of atoms on each other is traced. Therefore, substitution reactions with halogens in it proceed much faster than in benzene. Moreover, the process does not require heating and the presence of a catalyst. Immediately three hydrogen atoms in the phenol molecule are replaced by bromine radicals. As a result of the reaction, tribromophenol is formed.

Oxygen compounds of bromine

Let's continue studying the question of what bromine is. The interaction of halogen with cold water leads to the formation of hypochlorous acid HBrO. It is weaker than the chlorine compound by reducing its oxidizing properties. Another compound, bromic acid, can be obtained by oxidizing bromine water with chlorine. Earlier in chemistry, it was believed that bromine could not have compounds in which it could exhibit an oxidation state of +7. However, by oxidation of potassium bromate, a salt was obtained - potassium bromate, and from it - and the corresponding acid - HBrO 4. Halogen ions have reducing properties: when HBr molecules act on metals, the latter are oxidized by hydrogen cations. Therefore, only those metallic elements that are in the activity series up to hydrogen interact with the acid. As a result of the reaction, medium salts are formed - bromides, and free hydrogen is released.

The use of bromine compounds

The high oxidizing ability of bromine, whose mass is quite large, is widely used in analytical chemistry, as well as in the chemistry of organic synthesis. In agriculture, preparations containing bromine are used in the fight against weeds and insect pests. Flame retardants - substances that prevent spontaneous combustion, are used to impregnate building materials, plastics, fabrics. In medicine, the inhibitory effect of salts: potassium and sodium bromide - on the passage of bioelectric impulses along nerve fibers has long been known. They are used in the treatment of disorders of the nervous system: hysteria, neurasthenia, epilepsy. Given the strong toxicity of the compounds, the dosage of the drug should be controlled by a doctor.

In our article, we found out what bromine is, and what physical and chemical properties are characteristic of it.

Br 2 at ordinary temperature is a brownish-brown heavy liquid that forms toxic red-brown vapors with a pungent odor. The solubility of bromine in water is higher than that of chlorine. A saturated solution of Br 2 in water is called "bromine water".

Free I 2 at ordinary temperature is a black-gray solid with a violet tint, has a noticeable metallic luster. Iodine sublimes easily, has a peculiar smell (iodine vapor, like bromine, is very poisonous). The solubility of I 2 in water is the smallest among all halogens, but it dissolves well in alcohol and other organic solvents.

How to get

1. Bromine and iodine are extracted from sea water, underground brines and drilling waters, where they are contained in the form of Br - and I - anions. The release of free halogens is carried out using various oxidizing agents, most often gaseous chlorine is passed through:

2NaI + Cl 2 \u003d I 2 + 2NaCl

2NaBr + Cl 2 \u003d Br 2 + 2NaCI

2. Under laboratory conditions, for example, the following reactions are used to obtain Br 2 and I 2:

2NaBr + MnO 2 + 2H 2 SO 4 = Br 2 ↓ + MnSO 4 + Na 2 SO 4 + 2H 2 O

bHBr + 2H 2 SO 4 = 3Br 2 ↓ + S↓ + 4Н 2 O

2HI + H 2 SO 4 \u003d I 2 ↓ + SO 2 + 2H 2 O

Chemical properties

Bromine and iodine are chemically similar to chlorine. The differences are mainly related to the reaction conditions. Let us note some important features of chemical reactions involving Br 2 and I 2 .

Br 2 is a very strong oxidizer

Bromine is a liquid, unlike gaseous Cl 2, so the concentration of molecules in it is higher. This explains the stronger oxidizing effect of liquid bromine. For example, when iron and aluminum come into contact with it, ignition occurs even at ordinary temperatures.

Bromine water - a reagent for conducting qualitative reactions

Bromine water has a yellow-brown color, which quickly disappears if the dissolved Br 2 reacts with any substance. "Bromine water decolorization" is a test for the presence in a solution of a number of inorganic and organic substances.

1. Detection of reducing agents in solutions

Gaseous and dissolved in water SO 2 and H 2 S, as well as soluble sulfites and sulfides decolorize bromine water:

Br 2 + Na 2 SO 3 + H 2 O \u003d 2HBr + Na 2 SO 4

Br 2 + H 2 S \u003d 2HBr + S ↓

3Br 2 + Na 2 S + ZN 2 O \u003d 6HBr + Na 2 SO 3

2. Detection of multiple carbon-carbon bonds

Qualitative reaction to unsaturated organic compounds - discoloration of bromine water:

R-CH=CH-R" + Br 2 → R-CHBr-CHBr-R"

3. Detection of phenol and aniline in organic solutions

Phenol and aniline easily interact with bromine water, and the reaction products do not dissolve in organic solvents, therefore they form precipitates:

C 6 H 5 OH + ZBr 2 → C 6 H 2 Br 3 OH ↓ + ZHBr 2

С 6 Н 5 NH 2 + ЗВr 2 → С 6 H 2 Br 3 NH 2 ↓ + ЗНВr

Iodine-starch reaction in a qualitative analysis

Anions I - are very easily oxidized by both strong and weak oxidizing agents:

2I - -2e - → I 2

Even small amounts of I 2 released can be detected using a starch solution, which acquires a characteristic dirty blue color in the presence of I 2 . Iodine-starch reaction is used in carrying out not only qualitative analysis, but also quantitative.

Reactions involving I 2 as a reducing agent

Iodine atoms have lower electron affinity and EO values ​​than other halogens. On the other hand, the manifestation of some metallicity in iodine is explained by a significant decrease in the ionization energy, due to which its atoms give up electrons much more easily. In reactions with strong oxidizing agents, iodine behaves as a reducing agent, for example:

I 2 + I0HNO 3 \u003d 2HIO 3 + 10NO 2 + 4H 2 O

I 2 + 5H 2 O 2 \u003d 2HIO 3 + 4H 2 O

I 2 + 5Cl 2 + 6H 2 O \u003d 2HIO 3 + 10HCl

Hydrogen bromide and hydrogen iodide

HBr and HI are very similar in physical and chemical properties to HCl, therefore, attention should be paid only to practically important differences that must be taken into account when obtaining these substances.

Thermal instability HBr and HI

HBr and HI molecules are less stable than HCl, so their synthesis from simple substances is difficult due to the reversibility of the reaction (especially in the case of HI).

H 2 + I 2 → 2HI

Br - and I - anions are stronger reducing agents than Cl - anions.

HCI is obtained by the action of conc. H 2 SO 4 to chlorides (for example, solid NaCl). Hydrogen bromide and hydrogen iodide cannot be obtained in this way, since they are oxidized with conc. H 2 SO 4 to free halogens:

2KVg + 2H 2 SO 4 \u003d Br 2 + SO 2 + 2H 2 O + K 2 SO 4

6KI + 4H 2 SO 4 \u003d 3I 2 + S + 4H 2 O + 3K 2 SO 4

Obtaining HBr and HI:

1) from bromides and iodides

It is necessary to displace HBr and HI from their salts with non-volatile non-oxidizing phosphoric acid

KVg + H 3 PO 4 \u003d HBr + KN 2 PO 4

2) hydrolysis of non-metal halides

KI + H 3 PO 4 \u003d HI + KN 2 PO 4

3) reduction of free halogens in aqueous solutions

РВr 3 + ЗН 2 O = H 3 PO 3 + ЗНВr

PI 3 + ZN 2 O \u003d H 3 PO 3 + 3HI

Br 2 + SO 2 + 2H 2 O \u003d 2HBr + H 2 SO 4

l 2 + H 2 S = 2HI + S↓

4Br 2 + BaS + 4Н 2 O = 8HBr + BaSO 4

Bromine

BROMINE-a (-y); m.[from Greek. brōmos - bad smell]

1. A chemical element (Br), a heavy reddish-brown toxic liquid that smokes in air (used in chemical production, in the form of salts - in medicine and photography). Bromine salts. Bromine potion.

2. A drug containing this substance or its compounds (used as a sedative or hypnotic). Write out, take b. Drop bromine (bromine).

◁ Bromine, th, th. B drugs. B-th water(aqueous solution of bromine). Bromine, th, th. B drugs. Bromine, th, th. B-th salts, metals. Potassium bromide solution(soothing drops).

(lat. Bromum), a chemical element of group VII of the periodic system, refers to halogens. Name from Greek. brōmos - stench. Heavy red-brown liquid fuming in air with a sharp unpleasant odor; density 3.1 g / cm 3, t pl -7.25°C, t kip 59.2°C. It is used as a brominating agent, for the production of bromides, organic and other bromine compounds, in analytical chemistry. Bromine is poisonous.

BROMINE (lat. Bromum), Br (read "bromine"), a chemical element with atomic number 35, atomic mass 79.904. The name is due to the fact that bromine has a heavy, unpleasant smell of vapors (from the Greek bromos - stench).
Natural bromine is a mixture of two nuclides (cm. NUCLIDE) with mass numbers 79 (in a mixture of 50.56% by mass) and 81. Configuration of the outer electron layer 4 s 2 p 5 . In compounds, it exhibits oxidation states –1, +1, +3, +5 and +7 (valences I, III, V and VII), with the most characteristic oxidation states being –1 and +5.
It is located in the fourth period in group VIIA of the periodic system of elements of Mendeleev, refers to halogens (cm. HALOGENS).
The radius of the neutral bromine atom is 0.119 nm, the ionic radii of Br - , Br 3+ , Br 5+ and Br 7+ are, respectively, 0.182, 0.073, 0.045 and 0.039 nm. The sequential ionization energies of a neutral bromine atom are 11.84, 21.80, 35.9, 47.3, and 59.7 eV, respectively. Electron affinity 3.37 eV. According to the Pauling scale, the electronegativity of bromine is 2.8.
Discovery history
The discovery of bromine led to the research of the French chemist A. Balar (cm. BALAR Antoine Gerome), who in 1825, acting with chlorine on an aqueous solution obtained after washing the ashes of seaweed, isolated a dark brown, foul-smelling liquid. He called this liquid, also obtained from sea water, muride (from Latin muria - salt solution, brine) and sent a message about his discovery to the Paris Academy of Sciences. The commission set up to verify this report did not accept the name Balar and named the new element bromine. The discovery of bromine made the young and little-known scientist famous. After the appearance of Balar's article, it turned out that flasks with a similar substance were awaiting research from the German chemists K. Levig and J. Liebig (cm. LIBICH Justus). Having missed the opportunity to discover a new element, Liebig exclaimed: "It was not Balar who discovered bromine, but bromine discovered Balar."
Being in nature
Bromine is a fairly rare element in the earth's crust. Its content in it is estimated at 0.37·10 -4% (about 50th place).
Chemically, bromine is highly active and therefore does not occur in nature in free form. It is part of a large number of different compounds (sodium, potassium, magnesium bromides, etc.), accompanying sodium, potassium and magnesium chlorides. Bromine's own minerals - bromargyrite (silver bromide AgBr) and embolite (mixed chloride and silver bromide) - are extremely rare (see Natural bromides (cm. NATURAL BROMIDES)). The source of bromine is the waters of bitter lakes, salt brines associated with oil and various salt deposits, and sea water (65 10 -4%), the Dead Sea is richer in bromine. At present, bromine is usually extracted from the waters of some bitter lakes, one of which is located, in particular, in our country in the Kulunda steppe (in Altai).
Physical and chemical properties
Under normal conditions, bromine is a heavy (density 3.1055 g / cm 3) red-brown thick liquid with a pungent odor. Bromine is one of the simple substances that are liquid under normal conditions (except for bromine, mercury is also such a substance). The melting point of bromine is -7.25 °C, the boiling point is +59.2 °C. The standard electrode potential Br 2 /Br - in an aqueous solution is +1.065 V.
It exists in free form in the form of diatomic molecules Br 2 . A noticeable dissociation of molecules into atoms is observed at a temperature of 800 °C and rapidly increases with a further increase in temperature. The diameter of the Br 2 molecule is 0.323 nm, the internuclear distance in this molecule is 0.228 nm.
Bromine is slightly, but better than other halogens, soluble in water (3.58 g in 100 g of water at 20 ° C), the solution is called bromine water. In bromine water, a reaction proceeds with the formation of hydrobromic and unstable hypobromous acids:
Br 2 + H 2 O \u003d HBr + HBrO.
With most organic solvents, bromine is miscible in all respects, and bromination of organic solvent molecules often occurs.
Bromine is intermediate in chemical activity between chlorine and iodine. When bromine reacts with iodide solutions, free iodine is released:
Br 2 + 2KI = I 2 + 2KBr.
On the contrary, under the action of chlorine on bromides in aqueous solutions, free bromine is released:
Cl 2 + 2NaBr \u003d Br 2 + 2NaCl.
The reaction of bromine with sulfur produces S 2 Br 2, the reaction of bromine with phosphorus produces PBr 3 and PBr 5. Bromine also reacts with non-metals selenium (cm. SELENIUM) and tellurium (cm. TELLURIUM) .
The reaction of bromine with hydrogen proceeds when heated and leads to the formation of hydrogen bromide HBr. A solution of HBr in water is hydrobromic acid, similar in strength to hydrochloric acid HCl. Salts of hydrobromic acid - bromides (NaBr, MgBr 2, AlBr 3, etc.). A qualitative reaction to the presence of bromide ions in a solution is the formation of a light yellow AgBr precipitate with Ag + ions, which is practically insoluble both in water and in a nitric acid solution.
Bromine does not directly react with oxygen and nitrogen. Bromine forms a large number of different compounds with other halogens. For example, bromine forms unstable BrF 3 and BrF 5 with fluorine, and IBr with iodine. When interacting with many metals, bromine forms bromides, for example, AlBr 3, CuBr 2, MgBr 2, etc. Tantalum and platinum are resistant to the action of bromine, to a lesser extent - silver, titanium and lead.
Bromine is a strong oxidizing agent, it oxidizes the sulfite ion to sulfate, the nitrite ion to nitrate, etc.
When interacting with organic compounds containing a double bond, bromine is added, giving the corresponding dibromo derivatives:
C 2 H 4 + Br 2 \u003d C 2 H 4 Br 2.
Bromine also joins organic molecules, which contain a triple bond. The discoloration of bromine water when a gas is passed through it or a liquid is added to it indicates that an unsaturated compound is present in the gas or liquid.
When heated in the presence of a catalyst, bromine reacts with benzene to form bromobenzene C 6 H 5 Br (substitution reaction).
When bromine interacts with alkali solutions and with solutions of sodium or potassium carbonates, the corresponding bromides and bromates are formed, for example:
Br 2 + 3Na 2 CO 3 \u003d 5NaBr + NaBrO 3 + 3CO 2.
Application
Bromine is used in the preparation of a number of inorganic and organic substances, in analytical chemistry. Bromine compounds are used as fuel additives, pesticides, flame retardants, and in photography. Drugs containing bromine are widely known. It should be noted that the common expression: “the doctor prescribed bromine in a tablespoon after eating” means, of course, only that an aqueous solution of sodium (or potassium) bromide is prescribed, and not pure bromine. The sedative effect of bromine preparations is based on their ability to enhance the processes of inhibition (cm. BRAKING) in the central nervous system.
Features of working with bromine
When working with bromine, protective clothing, gas masks, and gloves should be used. Maximum concentration limit for bromine vapors is 0.5 mg/m 3 . Already at the content of bromine in the air at a concentration of about 0.001% (by volume), irritation of the mucous membranes, dizziness, and at higher concentrations - spasms of the respiratory tract, suffocation are observed. When ingested, the toxic dose is 3 g, the lethal dose is from 35 g. In case of poisoning with bromine vapor, the victim must be immediately removed to fresh air; to restore breathing, you can use a swab moistened with ammonia, periodically bringing it to the victim's nose for a short time. Further treatment should be carried out under medical supervision. Liquid bromine on contact with the skin causes painful burns.
Due to the high chemical activity and toxicity of both bromine vapor and liquid bromine, it should be stored in a glass, tightly sealed thick-walled container. Vials with bromine are placed in containers with sand, which protects the flasks from destruction when shaken. Due to the high density of bromine, bottles with it should never be taken only by the throat (the throat may come off, and then the poisonous liquid will be on the floor).
To neutralize the spilled bromine, the surface with it must be immediately covered with a slurry of wet soda Na 2 CO 3.

encyclopedic Dictionary. 2009 .

See what "bromine" is in other dictionaries:

bromine- bromine, and y ... Russian spelling dictionary

bromine- bromine / ... Morphemic spelling dictionary

BROMINE- BROMINE, Bromum (from the Greek bromos stench), liquid metalloid, halide group, with chem. the designation Vg; at. in. 79.92; occupies 35th place in the periodic system of elements, 4th in group VII. Dark red-brown liquid, ud. weight 3.188… … Big Medical Encyclopedia

- (Greek bromos fetid). Simple liquid body red, with a very unpleasant odor; discovered by Balard in 1726 in sea water and salt springs. Dictionary of foreign words included in the Russian language. Chudinov A.N., 1910. BROMINE ... ... Dictionary of foreign words of the Russian language

BROMINE, bromine, husband. (Greek bromos bad smell). Chemical element, caustic brown-red liquid with a strong odor (chemical). Bromine is used in medicine, photography and technology. || Bromine compounds, use. in medicine (apt.). The doctor prescribed... Explanatory Dictionary of Ushakov

- (symbol Br), volatile, liquid element of the HALOGEN group (seventh group of the periodic table). It was first isolated in 1826. It is the only non-metallic element that remains liquid at room temperature. It is extracted from soluble ... Scientific and technical encyclopedic dictionary

- (Bromum), Br, chemical element of group VII of the periodic system, atomic number 35, atomic mass 79.904; refers to halogens; heavy red liquid, mp 7.25shC, bp 59.2shC. Various Br compounds are used in medicine, photography, optics… Modern Encyclopedia

- (lat. Bromum) Br, a chemical element of group VII of the periodic system, atomic number 35, atomic mass 79.904, refers to halogens. Named from the Greek bromos stench. Heavy reddish-brown liquid fuming in air with a sharp unpleasant odor; ... ... Big Encyclopedic Dictionary

Bromine ... The initial part of compound words, introducing the meanings of the words: bromine, bromide (bromide, bromoacetone, organobromine, silver bromine, etc.). Explanatory Dictionary of Ephraim. T. F. Efremova. 2000... Modern explanatory dictionary of the Russian language Efremova

BROM, a, husband. A chemical element, a red-brown caustic liquid fuming in air, used. in chemistry, as well as in medicine, photography. | adj. bromine, oh, oh and bromine, oh, oh. Explanatory dictionary of Ozhegov. S.I. Ozhegov, N.Yu. Shvedova. 1949 1992 ... Explanatory dictionary of Ozhegov