Bromine is the origin of the name. Bromine is a poisonous element with interesting properties. Bromine in the body
Distantly reminiscent of the smell of iodine and chlorine at the same time. Flying, poisonous. The bromine molecule is diatomic (formula Br 2).
Story
Liquid bromine easily interacts with gold, forming gold tribromide AuBr 3:
2 A u + 3 B r 2 → 2 A u B r 3 (\displaystyle (\mathsf (2Au+3Br_(2)\rightarrow 2AuBr_(3))))Application
In chemistry
- Bromine-based substances are widely used in organic synthesis.
- " Bromine water" (an aqueous solution of bromine) is used as a reagent for the qualitative determination of unsaturated organic compounds.
Industrial Application
A significant part of elemental bromine was used until the early 1980s to produce 1,2-dibromoethane, which was part of the ethyl liquid, an antiknock additive in gasoline, containing tetraethyl lead; dibromoethane in this case served as a source of bromine to form relatively volatile lead dibromide to prevent the deposition of solid lead oxides on engine parts. Bromine is also used in the synthesis of flame retardants - additives that give fire resistance to plastics, wood, and textile materials.
- Silver bromide AgBr is used in photography as a photosensitive substance.
- Bromine pentafluoride is sometimes used as a very powerful propellant oxidizer.
- Bromide solutions are used in oil production.
- Solutions of heavy metal bromides are used as "heavy liquids" in the enrichment of minerals by the flotation method.
- Many organobromine compounds are used as insecticides and pesticides.
In medicine
- In medicine, sodium bromide and potassium bromide are used as sedatives.
In the production of weapons
Physiological action
Bromine and its vapors are toxic. Already at a concentration of bromine in the air at a concentration of about 0.001% (by volume), irritation of the mucous membranes, dizziness, nosebleeds are observed, and at higher concentrations, airway spasms, suffocation. MPC of bromine vapor - 0.5 mg / m³. The oral LD 50 for rats is 1700 mg/kg. For humans, the lethal oral dose is 14 mg/kg. In case of poisoning with bromine vapor, the victim should be immediately removed to fresh air (oxygen inhalation is shown as early as possible); 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. Recommended inhalations
Bromine is a simple substance, halogen, discovered at the beginning of the 19th century. Not the most common element on Earth, but widely scattered: it can be found in the seas and oceans, in lakes and groundwater, in earth's crust, atmosphere, in plants (legumes, seaweeds). It is not found in its pure form due to its high chemical activity. There are few bromine minerals and they have no industrial value. They extract bromine from sea water, bitter lakes, groundwater associated with oil fields.
Properties
Heavy dark red liquid. Only bromine and mercury of all simple substances are liquids under normal conditions. The smell is unpleasant, it was he who gave the name to the substance (from the Greek "bromos", meaning a bad smell). It is poorly soluble in water, although better than other halogens. Mixes up with organic solvents in any proportions.
The reactive element, a strong oxidizing agent, forms a fairly strong hydrobromic acid HBr. In addition, it forms a number of oxygen-containing acids. Reacts with halogens, non-metals, metals. Does not react with oxygen, nitrogen, platinum, tantalum. Forms bromides, easily joins organic compounds.
It is necessary to distinguish between bromine, as a chemical element, and the medicine "bromine", which is prescribed in the clinic as a sedative. Bromine is very toxic, and for medical purposes, potassium bromide or sodium bromide is used, which enhance the processes of inhibition in the central nervous system.
Bromine and its vapors are poisonous, and liquid bromine causes long-term non-healing chemical burns when it comes into contact with the skin. It is allowed to work with the reagent only with the use of all protective equipment, including special clothing, gloves and a gas mask. Inhalation of bromine vapor is especially dangerous for people with respiratory diseases, as pulmonary edema may develop. In case of bromine poisoning, a person should be provided with fresh air or oxygen inhalation and call a doctor. Helps warm milk, soda, soda-containing mineral water, coffee. Sodium thiosulfate solution serves as an antidote and neutralizer for bromine spills. It can also be impregnated into face dressings to protect against fumes. For small spills, ordinary baking soda will do, but the reaction with bromine is exothermic, causing the air temperature to rise and increasing fumes, so it's best to have sodium thiosulfate on hand.
Application
- In the chemical industry, bromine is used to produce organic and inorganic compounds, such as potassium and sodium bromide, hydrobromic acid, dibromoethane, and many others.
- Bromine is in demand for high quality rubber.
- For analytical purposes, bromine, bromine water, potassium bromide, sodium bromide are used.
- Silver bromide is used as a photosensitive material in photography.
- Almost half of the produced bromine is used to obtain 1,2 dibromoethane, which is part of the fuel as an anti-knock additive, used to protect wood from damage by insects, in organic synthesis.
- Bromine is widely used to produce flame retardants - special additives and impregnations that give paints, plastics, wood, textile materials fire-fighting properties.
- Bromochloromethane is used to fill fire extinguishers. 
- Bromine pentafluoride is used in rocket fuel.
- AT agriculture bromine compounds are used to control plant pests.
- Solutions of bromides are used in oil production, mining and processing plants.
- In medicine, solutions of KBr and NaBr are part of sedatives, for example, in the composition of Corvalol.
- Bromine can be used as a disinfectant to replace chlorine in swimming pools, water treatment plants.
Potassium bromide, sodium bromide, hydrobromic acid, standard titer potassium bromide are sold in our online store at competitive prices.
| atomic number | 35 |
| Appearance a simple substance | red-brown liquid with a strong unpleasant odor |
| Atom properties | |
| Atomic mass (molar mass) |
79.904 a. e.m. (g/mol) |
| Atom radius | n/a pm |
| Ionization energy (first electron) |
1142.0 (11.84) kJ/mol (eV) |
| Electronic configuration | 3d 10 4s 2 4p 5 |
| Chemical properties | |
| covalent radius | 114 pm |
| Ion radius | (+5e)47 (-1e)196 pm |
| Electronegativity (according to Pauling) |
2,96 |
| Electrode potential | 0 |
| Oxidation states | 7, 5, 3, 1, -1 |
| Thermodynamic properties of a simple substance | |
| Density | 3.12 g/cm³ |
| Molar heat capacity | 75.69 J/(K mol) |
| Thermal conductivity | 0.005 W/(m K) |
| Melting temperature | 265.9K |
| Melting heat | (Br—Br) 10.57 kJ/mol |
| Boiling temperature | 331.9K |
| Heat of evaporation | (Br—Br) 29.56 kJ/mol |
| Molar volume | 23.5 cm³/mol |
| The crystal lattice of a simple substance | |
| Lattice structure | orthorhombic |
| Lattice parameters | a=6.67 b=4.48 c=8.72 Å |
| c/a ratio | — |
| Debye temperature | n/a K |
| Br | 35 |
| 79,904 | |
| 3d 10 4s 2 4p 5 | |
- 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 Antoine Balard, unknown to anyone, 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 it physical properties, and also 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 number 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 the halogen with cold water leads to the production 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. Fire retardants - substances that prevent spontaneous combustion are used for impregnation 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 physician.
In our article, we found out what bromine is, and what physical and Chemical properties characteristic of him.
DEFINITION
Bromine- a chemical element located in the fourth period in the VIIA group of the Periodic Table of D.I. Mendeleev.
The serial number is 35. The structure of the atom is shown in fig. 1. Non-metal of the p-family.
Rice. 1. Scheme of the structure of the bromine atom.
Under normal conditions, bromine is a red-brown liquid with a sharp unpleasant odor. Poisonous. Density 3.19 g/cm 3 (at t 0 = 0 o C). When boiling (t 0 \u003d 58.6 o C), bromine passes from a liquid state into a gaseous state - it forms a brown-brown vapor.
The relative atomic mass of atomic bromine is 79.904 amu. Its relative molecular weight will be 79.904, and the molar mass will be:
M(Br 2) \u003d M r (Br 2) × 1 mol \u003d 79.904 g / mol.
It is known that the bromine molecule is diatomic - Br 2, then the relative atomic mass of the bromine molecule will be equal to:
A r (Br 2) \u003d 79.904 × 2 \u003d 159.808 a.m.u.
The relative molecular weight of a bromine molecule will be equal to 159.808, and the molar mass:
M(Br 2) \u003d M r (Br 2) × 1 mol \u003d 159.808 g / mol, or simply 160 g / mol.
Examples of problem solving
EXAMPLE 1
| Exercise | Write the reaction equations in accordance with the transformation scheme: Br 2 → NaBr → Br 2 → HBr → KBr → AgBr. |
| Answer | In order to obtain sodium bromide from bromine water, it is necessary to act on it with a dilute solution of sodium hydroxide. The reaction takes place at a temperature of 0 - 5 o C. Br 2 + 2NaBr dulute \u003d NaBr + NaBrO + H 2 O. It is possible to obtain bromine from sodium bromide if dilute sulfuric acid (10-50%) is added to the salt (in the solid state of aggregation): 2NaBr + H 2 SO 4 (dilute) = Na 2 SO 4 + 2HBr. To obtain hydrogen bromide from bromine water, hydrogen must be added to the reaction mixture: Br 2 + H 2 = 2HBr. Potassium bromide is formed as a result of the interaction of dilute solutions of hydrogen bromide and potassium hydroxide: HBr dilute + KOH dilute \u003d KBr + H 2 O. A yellow precipitate - silver bromide can be obtained by acting on silver nitrate with a solution of potassium bromide: KBr + AgNO 3 = AgBr↓ + KNO 3 . |
