Cobalt is a chemical element. Cobalt in the human body

An ordinary person not connected with chemistry and medicine, as a rule, vaguely represents the value of cobalt for his life and health. Another reason why we are at a loss to explain what cobalt is is its meager distribution in nature. Only 0.004% is its content in the earth's crust. However, the metal and its compounds are actively used in metallurgy, agriculture and medicine. In this article, we will expand our understanding of the role of cobalt in industry, and also dwell on its functions in the human body.

Place of the element in the periodic table

What is the place in the periodic system of cobalt? The properties of chemical elements, including the metal we are considering, depend on their position in the table of DI Mendeleyev. It is located in the VIII b group (in the short form of the table - in the triad of iron group VIII). As in iron and nickel, in its atom at the last energy level there are two electrons, which indicates that the metal belongs to the d-elements and determines its main characteristics. The metal has two valencies - II and III. It is also characterized by the phenomenon of allotropy, metal modifications can have a cubic or hexagonal structure.

What is cobalt?

What are the physical properties of the element? In appearance it is a metal with high hardness and magnetic properties. Silvery luster, viscidity and thermal stability - these are some of the physical features of the element, which are also characteristic of its two neighbors in the periodic system - nickel and iron. Neither oxygen nor water acts on cobalt at ordinary temperature. Its compounds, for example, smalt, have been known for a long time, as substances used for the production of blue stained glass and the staining of ceramic products.

Cobalt is a typical metal, similar to its chemical properties on iron. What are the characteristics of its oxides, bases and salts?

Compounds of divalent and trivalent cobalt

The ability to form complex salts is the main distinguishing feature of Co (III) atoms. These substances are not very stable, the coordination number of cobalt in them is always six. They have a high oxidizing ability. Average salts, for example, CoCL ₃ or Co ₂ (SO ₄ ) _3, easily transform into salts in which cobalt is already a divalent metal. Its anhydrous compounds have a blue color, and crystalline hydrates and solutions are pink. Unlike other bases, the hydroxide of trivalent cobalt, when interacted with chloride acid, does not form salt and water, but liberates free chlorine from it. The base of the divalent metal in the form of a blue precipitate is obtained by direct reaction of the corresponding salt with an alkali. We give a description of the properties of cobalt, which is part of the solid solutions of metals in each other - alloys.

It gives the material exceptional technical parameters of resistance to high temperatures, hardness, resistance to abrasion and corrosion. Alloys containing cobalt are used in the defense industry, rocket engineering and in closed-cycle chemical technologies. In the production of instrumental grades of steel, materials with magnetic properties, as an alloying additive, cobalt is also used. The characteristics of the properties of such iron alloys are very different from the usual grades of stainless steel containing only chromium or nickel.

Application of cobalt in engineering

About a third of all metal produced in the world goes to the production of cermets - artificial composite materials. A solid base in them is tungsten carbide, and cobalt is the binding and fixing component. It is also a strategic raw material for the production of turbine engines in aircraft construction.

In pure form, metal is practically not used, but the use of cobalt in a mixture with other elements (iron, copper, tungsten and chromium) is widespread in various industries. Alloy stellite, containing up to 60% cobalt, is distinguished by its high heat resistance and hardness, it is an indispensable material for the manufacture of cutters and drills in tool production. Such alloying elements, as tungsten and molybdenum, enhance its characteristics. Alloy Vitalium, which has a high resistance to plastic deformation, also contains cobalt. Characteristics of the properties of the compound are as follows: heat-resistant and acid-resistant, it is used in the manufacture of chemical equipment: synthesis columns, distillation apparatuses. The role of alloys in counteracting various types of corrosion is great, for example, parts and mechanisms made of stellite are resistant to destruction during vibrational and rubbing movements of mechanical surfaces in internal combustion engines.

Methods for obtaining cobalt

Different branches of the economy require the use of materials containing cobalt. This contributes to an increase in the extraction of ores and minerals, namely: cobalt spikes and gloss. The composition of these rocks also includes arsenic, which forces to apply increased safety measures in the processes of metal smelting. The main method of obtaining cobalt is pyrometallurgy, and a method for treating ore with sulfate acid is also used. The most promising are deposits of silicate-oxide ores, pyrite and pentlandite in China, Russia (on the Kola Peninsula, in the Republic of Tuva and the Krasnoyarsk Territory), as well as in Canada.

The use of metal in agriculture and medicine

Certain important properties possessed by the microelement of cobalt, promote its use, for example, in plant growing to increase the vegetative mass of plants. In alfalfa, lupine, clover and other valuable forage grasses of the legume family, it is included in the enzymatic reactions of nitrogen fixation, occurring with the help of nodule bacteria. The lack of a microelement is manifested by such symptoms as discoloration of leaf blades and loss of their ability for photosynthesis, slowing down of growth processes and violation of the entire cycle of plant development. Excessive content of cobalt is possible due to violation of the rates of application of microfertilizers. Since its compounds are readily soluble in water, they immediately enter the xylem and pass through the mesophyll of the leaf through the conductive elements (vascular fibrous fascicles), causing their discoloration and wilting. The cereal crops are most sensitive to an excess of a microelement: oats, barley, rice.

Biochemistry on the role of cobalt compounds

The branch of biology, which studies living matter at the molecular and cellular level, has established an important function of this chemical element. It is part of the non-protein part of biologically active substances - enzymes and hormones. For example, cobalt in the human body is a molecule of thyroxine, produced by the thyroid gland and controlling metabolic processes. Another vital hormone regulating the level of glucose in the blood plasma is insulin. It is secreted by β-cells of the islets of the pancreas Langerhans and also contains cobalt compounds. Insufficient intake of the element in cells and human organs is observed during the transition from mixed nutrition to vegetarianism, in helminthic invasions and diseases of the digestive system. As we see, cobalt is a microelement, which seriously affects the level of homeostasis in the human body.

The importance of a chemical element in metabolism

Bleeding, performed by the red bone marrow, occurs with the participation of cobalt-containing substances - activators of the corresponding enzymes. One of the main vitamins of group B - cyanocobalamin (B ₁₂ ), participating in the formation of erythrocytes in the blood-forming organs, protects the body from anemia. Correct and balanced nutrition, containing liver, beef, seafood, dried apricots, beetroot, will provide the necessary level of cobalt in the human body (about 40 mg per day) and protect it from diseases of the immune, cardiovascular and endocrine systems.