From chicken to human. Usually, they say: - "From the monkey." But, this is not about evolution, but about proving the importance boron for the body.

Until 1981, the element was considered insignificant, not requiring inclusion in the diet. The scientists' beliefs shook the chickens.

Their cultivation was more successful if the food included boron. Its necessity for chickens was proved in 1985, and by the 1990s it came to humans.

It turned out that boron is an element supporting bone density.

In addition, the substance keeps the normal production of both male and female hormones, that is, estrogen and progesterone.

Experiments have shown that taking boron preparations, people lose 40% less and 33% with .

Boron properties

Bor - chemical element standing in under the 5th number. The structure of matter is atomic.

This is typical for metals, however, boron does not apply to them. The element is an exception among its group of non-metals.

They, in fact, in the periodic system are on and above the line drawn from boron to.

Non-metals are characterized by a molecular structure, but, and the 5th substance is outside the rules.

The atomic lattice provides the hero with a record tensile strength of 5.7 hectopascals.

No wonder fibrous boron - chem. element added to composite materials.

They are created artificially by combining components with different properties. As a result, lightweight, but rigid, durable and wear-resistant structures are obtained.

Boron atoms consist of 5 protons and the same number, or 6, neutrons. Accordingly, there are two natural isotopes: - 10th and 11th.

5 particles rotate on the electron shells of an atom of an element. Two electrons are located in the orbit closest to the nucleus, and three are in the far one.

Therefore, the standard boron valence equals +3. Valency refers to the ability of an atom to form a certain number of chemical bonds with other elements.

Three electrons, ready to interact, provide the 5th element with high chemical activity.

Typical, for example, is the sintering reaction with metal powders. Borides are formed. The 5th substance “strives” and to. True, the formed borohydride is unstable.

But boron oxides resistant. The latter are obtained, as a rule, at high temperatures from oxides of other elements. Thus, boron can replace carbon in carbon monoxide, silicon in .

Boron compounds are the only representatives of it in nature. In a free form, the 5th element is obtained only in laboratories.

For the first time, the experiment was successful by Henri Moissan. The French chemist developed a magnesium-thermal method for obtaining pure boron. Element of the periodic table extracted during the reaction: B 2 O 3 + 3Mg -à3MgO + 2B.

At the same time, the final boron was contaminated with impurities by no more than 10%. It was possible to consider the appearance of the element.

It is hard, gray matter. It can only be melted at 4000 degrees Celsius.

The two natural isotopes of boron differ significantly in their characteristics, in particular, in the thermal neutron capture cross section.

The latter provoke atomic reactions. The capture cross section is the ability of the boron nucleus to capture slow neutrons. If the indicator is large, you can regulate the course of the reaction, stop it.

This means that substances with a large capture cross section are suitable for rods of nuclear reactors. Of the isotopes of boron, only one is suitable. Which one, we will tell in the next chapter.

Boron application

Lightweight is suitable for reactor rods boron isotope, that is, B10. It has not just a large capture cross section, but the first among all the elements of the periodic table.

The 11th bur, on the contrary, has the smallest indicator. Accordingly, a heavy version of the 5th substance can be used in the hot zone of the reactors. That is, B11 is an excellent structural material for nuclear power plants.

The nuclear power industry values ​​not only pure boron, but also its connection with .

This is the gas needed in thermal neutron counters. They are also called boron. The apparatus serves as a radiation receiver.

In nuclear reactors, and not only, by the way, the refractoriness and heat resistance of boron come in handy.

Therefore, the element becomes an addition to many . Most often, they saturate their surface.

This process is called boriding. Subjected to him, as a rule. Their surface becomes more durable and resistant to corrosion.

As a result, borated steel can serve in aggressive environments and withstand increased shock loads.

Boron carbides, that is, compounds with carbon, have long been used by dental technicians. Wondering why they're called that?

Because the drills in the devices are made of an alloy with the carbide of the 5th element. Such drilling of teeth is most quickly and efficiently.

Boron Formula c: — B 4 C. There is also a rarer compound B 13 C 2 . Both are excellent abrasives because, like .

The nitrides of the 5th substance, that is, its compounds with, are excellent semiconductors.

Their specific conductivity is greater than that of dielectrics, but less than that of metals.

Semiconductors are needed in integrated circuits, transistors, optoelectronics.

The secret of materials is that as the temperature rises, they begin to conduct current better. Ordinary conductors in heat, on the contrary, lose their properties.

Boron mining

In compounds, boron is extracted from the earth's interior. On average, there are 4 grams of the 5th element per ton of rock.

Most of all, about 100 micrograms per kilogram of rock, in boron. It is also searched for where there are alkaline soils.

They are the most saturated with the element. Interestingly, it can even be extracted from marine plants. In them, the 5th substance is 120 micrograms per kilo.

Of the minerals, ulexite is the richest in boron. Its deposits, for example, are being developed in Chile. The total reserves are estimated at 30,000,000 tons.

All deposits are located in the Atacama Desert. The first deliveries from here began in the middle of the 19th century, immediately after the construction of the railway in the country.

How much boron cost in those years is not said. However, we can find out the current price tag.

Boron price

The cost of production depends on the type and volume. So, in metallurgy you need a clean, amorphous boron.

Amorphous is a substance that does not have a crystal lattice.

If industrialists acquire a crystalline element, then it is as crushed as possible.

So, amorphous boron powder in a package of 15 kilograms costs about 9,000 rubles.

However, there are proposals where a kilo is estimated at only 50 rubles. Here you already need to collect a dossier on the supplier.

The reason for the low cost may be the contamination of boron, a large percentage of impurities. Although, there are also honest offers, especially with wholesale deliveries.

As for the compounds of the 5th element, for carbides they give from 100 to 700 rubles. This is the price tag for 1000 grams.

The spread of the cost is justified different formulas and properties of carbides. For a kilo of boric anhydrite, you have to pay around 250, and for nitride - several thousand rubles.

Meets and organobor. This is a complex fertilizer, because if the 5th element was not needed by plants, like the human body, it would not be extracted from algae. Typical packaging of organobor is liter. Its cost is 350-400 rubles.

Bor or Borum (lat.) is a non-metallic element. There are two forms: amorphous and crystalline. The amorphous type is a brown powder, odorless and tasteless. Has a very high melting point. The crystalline form of the element is garnet-red crystals. They are very hard, according to this indicator they can be compared with diamond and at the same time fragile. The element is chemically inert at standard temperature conditions.

The name of the element was given by the ancient name of one of the compounds "borax". Moreover, both in Latin and Arabic they were close: borax "and beetroot". It was discovered in 1808 almost simultaneously by two scientists - Gay-Lussac (France) and Denis (England), and they used different methods.

In nature, it occurs only in the form of boric acid or salts formed by it (borates and polyborates). AT earth's crust content is approximately one thousandth of a percent.

Element connections are often used in industrial production steel to increase hardness and resistance to high temperatures, which is necessary for the creation of nuclear reactors or rockets. it is actively used by the chemical (composites, detergents, photographic materials, fuel) and glass industries.

The action of boron and its biological role

The action of a macroelement on human life shows all its importance. Scientists have proven that boron is required by all living beings on this planet - plants, animals, and, of course, it is necessary for a person, and, accordingly, his biological role essential for the normal functioning of the body.

In our body, this substance is concentrated in the tissues of bones and tooth enamel, it even participates in their formation. There is also a lot of it in the brain, muscles, liver, lungs and kidneys. It is very important for men and their ability to procreate, because it is contained in the testes. Interestingly, the blood plasma of newborn babies is highly saturated with boron, but its amount begins to decrease very quickly, and during the first days of life.

It is difficult to overestimate the functions of boron and their influence on human life:

It is also able to relieve inflammation and reduce tumors.

Daily rate

The daily norm of a macronutrient is 1-3 mg. Dosages for men and women are different. For example, the stronger sex needs 0.6-1.5 mg, and beautiful ladies you need a little more - 1-2 mg. Problems may arise when receiving less than 0.2 mg and more than 4 grams.

Athletes, people with urolithiasis and menopausal women require an increase in daily norms, but taking into account the recommendations of a doctor.

Boron deficiency - what effect does a deficiency of an element have on the body?

A macronutrient deficiency is a rather rare phenomenon and can occur with insufficient intake from food and a violation of metabolism and digestibility.

The first symptoms are very similar to the manifestations of osteoporosis: problems with hair, nails and teeth, and may also appear pain in joints and bones. The central nervous system suffers, as a result of which a person becomes distracted, drowsy, his reactions slow down.

A longer deficiency of the element leads to unpleasant symptoms and diseases:

• osteoporosis in the elderly and in women during menopause;
• decreased immunity;
• changes in blood composition;
• growth retardation in children;
• decrease in brain activity and, accordingly, mental abilities;
• disruption of the endocrine system;
• difficult healing of wounds, injuries and fractures;
• predisposition to the development of diabetes mellitus.

Deficiency is quite easy to make up with the help of a competent diet.

Excess boron

An excess of a macronutrient can occur when taking boron-containing drugs; it is almost impossible to get an excessive amount of an element with food.

Regular overdose of 3 mg can cause signs of poisoning due to its toxic qualities. Loss of appetite, skin rashes, vomiting, diarrhea, headaches, anxiety. Longer and uncontrolled overdoses can cause diseases of the digestive system, diseases of the kidneys, liver and central nervous system.

Overabundance in the body can occur in industrial areas where environment(air, water and soil) are contaminated with toxic boron derivatives. In this case, symptoms such as irritation of the mucous eyes and nasopharynx, lung damage can appear quite quickly.

Usually, boron, after absorption, is excreted from the body through the kidneys, but in case of an overdose, it begins to accumulate in the intestines and stomach, causing irritation, inflammation and intoxication, which can also affect other organs.

Boron does not cause any effect on the external skin, except for very high concentrations, as well as does not cause mutational changes in the body.

Sources containing this substance

Products that contain boron can mainly be attributed to plant origin - these are nuts, prunes, raisins, legumes, grapes, apples, soybeans, honey, dates, seafood.

The drinking water of some regions of our planet contains a very large amount of the element. It is noteworthy that locals less often at times suffer from diseases of the joints.

Animal products (meat, fish, eggs, dairy products) are quite poor in boron content, so you can hardly count on them.

There is another interesting point - drinks such as cider, beer and wine are very rich in boron, but on condition that they are made according to classic recipes using natural products. However, do not overdo it in their use - there will be much more harm.

There are some substances, the interaction of boron with which can lead to unexpected consequences. For example, boron slows down the absorption of vitamin C, amino acids containing sulfur and copper. And, on the contrary, it is able to enhance the effect of alcohol and antibiotics.

Indications for appointment

Indications for the appointment of a macronutrient are reduced to the complex treatment of osteoporosis, the restoration of the condition of women during menopause.

BOR (Latin Borum), B, a chemical element of the III group of the short form (the 13th group of the long form) periodic system, atomic number 5, atomic mass 10.811; non-metal. There are two stable isotopes in nature: 10 V (19.9%) and 11 V (80.1%); artificially obtained isotopes with mass numbers 7-19.

History reference. Natural boron compounds, mainly borax, have been known since the early Middle Ages. Borax, or tinkal, was imported to Europe from Tibet, it was used in the forging of metals, mainly gold and silver. From the Arabic name buraq (burak) and the Late Latin borax (borax), the name of the element came from. Boron was discovered in 1808: J. Gay-Lussac and L. Tenard isolated the element from oxide B 2 O 3 by heating with metallic potassium, G. Davy - by electrolysis of molten B 2 O 3.

Distribution in nature. The content of boron in the earth's crust is 5·10 -3% by weight. It does not occur in free form. The most important minerals: borax Na 2 B 4 O 7 10H 2 O, kernite Na 2 B 4 O 7 -4H 2 O, colemanite Ca 2 B 6 O 11 5H 2 O, etc. Boron is concentrated in the form of potassium borates and alkaline earth elements in sedimentary rocks(see natural borates, boron ores).

Properties. External configuration electron shell boron atom 2s 2 2p 1 ; oxidation state +3, rarely +2; Pauling electronegativity 2.04; atomic radius 97 pm, ionic radius B 3+ 24 pm (coordination number 4), covalent radius 88 pm. Ionization energy B 0 → B + → B 2+ → B 3+ 801, 2427 and 3660 kJ/mol. The standard electrode potential of the B (OH) 3 / B 0 pair is -0.890 V.

Boron exists in several allotropic modifications. At temperatures below 800 °C, amorphous boron is formed (dark powder, density 2350 kg/m with a reddish tinge, the most stable), 1200-1500 ° C - tetragonal modifications. At temperatures above 1500 °C, the β-rhombohedral modification is stable. Crystal lattices of all types consist of B 12 icosahedrons differently packed in the crystal. For the β-rhombohedral modification: t PL 2074 °C, t KIP 3658 °C, density 2340 kg / m 3 (293 K), thermal conductivity 27.0 W / (m K) (300 K).

Boron is diamagnetic, specific magnetic susceptibility is -0.78·10 m 3 /kg. It is a p-type semiconductor with a band gap of 1.56 eV. The hardness of boron on the Mohs scale is 9.3. It is characterized by a high ability to absorb neutrons (for the 10 V isotope, the thermal neutron capture cross section is 3.8 10 -25 m 2).

Boron is chemically inert. It reacts with oxygen at temperatures above 700 ° C, forming a glassy oxide B 2 O 3. At temperatures above 1200 ° C, boron interacts with N 2 and NH 3, giving boron nitride BN. Forms with P and As at temperatures above 700 ° C phosphides and arsenides, which are high-temperature semiconductors. At temperatures above 2000 °C, boron reacts with carbon to form boron carbides. With halogens at elevated temperatures, it forms volatile trihalides, which are easily hydrolyzed and tend to form complexes of the H type; boron does not interact with hydrogen, water, acids, and alkali solutions. Concentrated HNO 3 and aqua regia oxidize boron to orthoboric acid H 3 BO 3 . Fusion of boron with alkalis in the presence of an oxidizing agent results in the formation of borates. Forms borides with metals at high temperatures. By the action of acids on borides, borohydrides can be obtained, which are characterized by addition reactions with the formation of metal borohydrides. For organoelement compounds of boron, see the article Organoboron compounds.

Boron belongs to microelements, its content in plant and animal tissues is 10-10-4%. Boron is involved in carbohydrate-phosphate metabolism. Human consumption of foods high in boron causes a violation of the metabolism of carbohydrates and proteins, which leads to gastrointestinal diseases. Boron is a biogenic element necessary for plant life. With a deficiency or excess of boron in plant tissues, usually associated with a deficiency or excess of the element in the soil, morphological changes and plant diseases occur (gigantism, dwarfism, impaired growth points, etc.). Small amounts of boron dramatically increase the yield of many crops (see Microfertilizers).

Receipt. In industry, boron is obtained from natural borates: colemanite and inioite are processed by the alkaline method with the release of boron in the form of borax, boracite is processed by the acid method with the formation of orthoboric acid, which is converted to B 2 O 3 at a temperature of about 235 ° C. Amorphous boron is obtained by reduction of borax or B 2 O 3 with active metals - Mg, Na, Ca, etc., as well as by electrolysis of a Na or K melt, Crystalline boron - by reduction of BCl 3 or BF 3 halides with hydrogen, decomposition of boron halides and hydrides (mainly B 2 H 6) at a temperature of 1000-1500 ° C or crystallization of amorphous boron.

Application. Boron is used as a component of corrosion-resistant and heat-resistant alloys, such as ferroboron - an alloy of Fe with 10-20% B, composite materials (boroplastics). A small addition of boron (fractions of a percent) significantly increases the mechanical properties of steel, non-ferrous metal alloys. The surface of steel products is saturated with boron (boriding) in order to improve mechanical and corrosion properties. Boron is used as a semiconductor for the manufacture of thermistors. About 50% of the obtained artificial and natural boron compounds are used in the production of glass, up to 30% - in the production of detergents. Many borides are used as cutting and abrasive materials. The Nd 2 Fe 14 V ferromagnet is used for the manufacture of powerful permanent magnets, the Co-Pt-Cr-B ferromagnetic alloy is used as a medium for recording in modern information media. Boron and its alloys are neutron absorbers in the production of control rods for nuclear reactors.

Lit.: Boron, its compounds and alloys. K., 1960; Golikova O., Samatov S. Bor and its semiconductor compounds. Tash., 1982; Boron chemistry at the millennium / Ed. R. V. King. Amst.; Oxf., 1999.

A. A. Eliseev, Yu. D. Tretyakov.

DEFINITION

Bor- fifth Element Periodic table. Designation - B from the Latin "borum". Located in the second period, IIIA group. Refers to non-metals. The nuclear charge is 5.

Boron is relatively uncommon in nature; the total content in the earth's crust is about 10 -3% (wt.).

The main natural boron compounds include boric acid H 3 BO 3 and salts of boric acids, of which borax Na 2 B 4 O 7 × 10H 2 O is best known.

Under normal conditions, boron is a substance of a crystalline structure (rhombohedral syngony) of a dark gray color (Fig. 1). Refractory (melting point 2075 o C, boiling point 3700 o C), diamagnetic, has semiconductor properties.

Rice. 1. Bor. Appearance.

Atomic and molecular weight of boron

Relative molecular weight M r is the molar mass of the molecule, referred to 1/12 of the molar mass of the carbon-12 atom (12 C). This is a dimensionless quantity.

Relative atomic mass A r is the molar mass of an atom of a substance, referred to 1/12 of the molar mass of a carbon-12 atom (12 C).

Since boron exists in the free state in the form of monatomic molecules B, the values ​​of its atomic and molecular weight match. They are equal to 10.806.

Allotropy and allotropic modifications of boron

Boron is characterized by the manifestation of allotropy, i.e. existence in the form of several simple substances called allotropic (allotropic) modifications. First, boron exists in two states of aggregation- crystalline (colored gray) and amorphous (colored white). Secondly, in the crystalline form, boron has more than 10 allotropic modifications. For example, boron atoms can be combined into groups B 12 that have the shape of an icosahedron - twenty-sided (Fig. 2).

Rice. 2. Icosahedral grouping of boron atoms B 12 .

These B 12 icosahedrons, in turn, can be located relative to each other in the crystal in different ways:

Boron isotopes

In nature, boron exists as two stable isotopes 10 B (19.8%) and 11 B (80.2%). Their mass numbers are 10 and 11, respectively. The 10 B boron isotope has five protons and five neutrons, while the 11 B isotope has the same number of protons and four neutrons.

There are twelve artificial (radioactive) isotopes of boron with mass numbers from 5 to 17, of which 8 B is the most stable, with a half-life of 0.77 s.

Boron ions

On the outer energy level of the boron atom, there are three electrons that are valence:

1s 2 2s 2 2p 1 .

As a result chemical interaction boron can lose its valence electrons, i.e. be their donor, and turn into a positively charged ion (B 3+) or accept electrons from another atom, i.e. be their acceptor, and turn into a negatively charged ion (B 3-):

B 0 -3e → B 3+;

B 0 +3e → B 3- .

Molecule and atom of boron

In the free state, boron exists in the form of monatomic molecules B. Here are some properties that characterize the atom and molecule of boron:

Boron alloys

In metallurgy, boron is used as an additive to steel and some non-ferrous alloys. The addition of very small amounts of boron reduces the grain size, which leads to an improvement in the mechanical properties of the alloys. Surface saturation of steel products with boron is also used - borating, which increases hardness and resistance to corrosion.

Examples of problem solving

EXAMPLE 1

EXAMPLE 2

Exercise	Find the formula for the compound of boron with hydrogen (borane), which has a composition in mass fractions of a percent: boron - 78.2; hydrogen - 21.8. If the mass of 1 cm 3 of this gas is equal to the mass of 1 cm 3 of nitrogen.
Solution	The mass fraction of the element X in the molecule of the HX composition is calculated by the following formula: ω (X) = n × Ar (X) / M (HX) × 100%. Let us denote the number of moles of elements that make up the compound as "x" (boron), "y" (hydrogen). Then, the molar ratio will look like this (values ​​of relative atomic masses taken from the Periodic Table of D.I. Mendeleev, rounded up to integers): x:y = ω(B)/Ar(B) : ω(H)/Ar(H); x:y= 78.2/11: 21.8/1; x:y= 7.12: 21.8= 1: 3. Means the simplest formula compounds of boron with hydrogen (borane) will have the form BH 3 and molar mass 14 g/mol. According to the condition of the problem: m (N 2) \u003d M (N 2) × V (N 2) / V m \u003d 28 × 1 / 22.4 \u003d 1.25 g. m(B x H y) = M(B x H y) × V(B x H y) / V m = M(B x H y) × 1 / 22.4. m(N 2) \u003d m (B x H y) \u003d M (B x H y) × 1 / 22.4; M (B x H y) \u003d m (N 2) × 22.4 \u003d 1.25 × 22.4 \u003d 28 g / mol. To find the true formula of a substance, we find the ratio of the obtained molar masses: M(B x H y) / M(BH 3) = 28 / 12 = 2. This means that the indices of boron and hydrogen atoms should be 2 times higher, i.e. the borane formula will look like B 2 H 6 .
Answer	B2H6

Boron is the fifth chemical element, belongs to the third group of the main subgroup of the periodic system of D. I. Mendeleev. It exhibits properties of both metals and non-metals. In the normal state, this is crystalline substance pale brown. The name boron comes from the Arabic word "borak", denoting one of the most common boron compounds in nature - the mineral borax. If boron is free of impurities, then it is colorless. It occurs naturally in various volcanic and sedimentary rocks. Boron compounds with impurities are also often found in the form of borosilicates, borates, and other minerals in which it is contained in small concentrations. Its compounds are present in most thermal springs, sea ​​water, as well as in the waters accompanying oil fields. In addition, boron is often found in many soil types.

Historical facts

The first free boron was obtained in 1808. French chemists Joseph Gay-Lussac and Louis Jacques Tenard, restoring boric anhydride, previously obtained by calcining boric acid, were able to obtain new element. However, the resulting substance contained a huge number of impurities. After 50 years, the physiochemist Henri St. Clair Deville and Friedrich Wöhler found that boron can exist in two modifications: in a crystalline diamond-like form and an amorphous form, most similar to graphite. However, in 1876, an article was published in which the German chemist L. Gampe argues that crystalline boron is not elemental at all, but is only a compound of aluminum boride AlB 12. Such a fate befalls graphite-like boron, the French chemist K. Joly gives a strange formula B 48 C 2 Al, which does not fit in with the classical theory of the valence of elements. Later, in 1908, the American Ezekiel Weintraub confirmed Gump's position on diamond-like boron and was the first to isolate this chemical element of 99% purity.

Boron chemical properties

Under normal conditions, boron does not show special properties and is therefore considered an inert element, reacting only with fluorine. Amorphous boron is more active than crystalline boron. However, with increasing temperature, the activity of boron increases, for example, at sufficiently high temperatures, boron begins to react with sulfur, oxygen, and some halogens. Boron begins to burn with a red flame when the temperature rises to 700⁰C. During combustion, boron anhydride is formed, which is a transparent glassy mass. With a further increase in temperature, boron reacts with nitrogen, forming boron nitrite, with carbon - carbide, and also with metals - borides. Boron is insoluble in acids at normal temperatures, with the exception of concentrated nitric acid. With alkali solutions, boron behaves more actively, slowly dissolving, it forms borates. Upon closer examination, boron reveals many properties in common with silicon, for example, boric acid, like silicic acid, has weak acidic properties and dissolves in hydrogen fluoride, forming gaseous compounds of boron and silicon, respectively.

Boron application

Boron is used in various steel alloys to improve certain qualities of the material, as well as corrosion resistance. The 10 V boron isotope is capable of retaining thermal neutrons, thanks to this feature it is used to create special rods that regulate the operation of nuclear reactors. The gaseous boron compound BF 3 has found application as neutron counters. Boron and compounds such as carbides, nitrides, phosphides and the like are widely used as dielectrics and are part of semiconductor materials. Boric acid, together with salts, is used in organic reactions as a catalyst. Also, boron derivatives are part of many types of rocket fuel.

Of particular interest is such a compound as boron nitride, which can form whole groups of compounds similar to organic carbon substances. For example, boron nitride hexahydride has a lot in common with ethane in structure. It is used as a fuel for electric vehicles.

Borax soap

• Boron plays an important role in plant life. With its deficiency, many processes associated with the oxidation of energy and the synthesis of necessary substances in plant tissues are disrupted. Timely fertilization of the soil prevents diseases in plants and increases yield.
• The gene that controls the concentration of boron inside the cell is also associated with one of the rare types of corneal depletion in the human eye.
• Every day, a person consumes from 1 to 3 mg of boron with food. In this case, a dose of about 4 g is considered toxic.
• Boron is actively involved in the growth of bone tissue, increasing the absorption of calcium. In addition, it affects the health of the joints and their mobility.
• For the beautiful green color of the flame, boron compounds are often added to fireworks.
• Boric acid is a kind of exception, because. because of their weaknesses acid properties it can be found in the earth's crust. As a result, it is often called mineral. If the acid is heated with boric acid, then another weak type of boron acid can be obtained - metaboric acid. However, there are very strong variants of boron acids, for example, complex fluoroboric acid H is the reaction product of the combination of hydrogen fluoride and boron trifluoride. In terms of its properties, this acid is in no way inferior to either hydrofluoric, or sulfuric, or hydrochloric acids.