Characteristics of the chemical element of germanium
The germanium chemical element is in the fourthgroup (subgroup main) in the table of Mendeleev elements. It belongs to the family of metals, its relative atomic mass is 73. By mass, the content of germanium in the earth's crust is estimated at 0.00007 percent by mass.
History of discovery
The chemical element of germanium was established due to the forecasts of Dmitri Ivanovich Mendeleyev. It was they who predicted the existence of ekasilicia, recommendations were given on its search.
Russian chemist believed that this metalthe element is in titanium, zirconium ores. Mendeleev tried to find this chemical element on his own, but his attempts were not crowned with success. Only fifteen years later, a mineral was discovered at the mine located in Himmelfurst, which was called argyrodite. The name of this compound is due to silver found in this mineral.
The chemical element germanium in the composition wasIt was discovered only after a group of chemists from the mountain academy of Freiberg started the research. Under the leadership of K. Winkler, they found out that only zinc, iron, and sulfur, mercury accounts for only 93 percent of the mineral. Winkler suggested that the remaining seven percent falls on an unknown chemical element at the time. After carrying out additional chemical experiments, germanium was detected. The chemist reported on his discovery in the report, presented information on the properties of the new element to the German Chemical Society.
The germanium chemical element was representedWinkler as a non-metal, by analogy with antimony and arsenic. The chemist wanted to call it neptunium, but this name was already used. Then it began to be called germanium. The chemical element discovered by Winkler aroused serious discussion among the leading chemists of the time. German scientist Richter suggested that this is the same ekasilicium, of which Mendeleev spoke. After some time this assumption was confirmed, which proved the viability of the periodic law created by the great Russian chemist.
How can you characterize germanium? The chemical element has 32 ordinal numbers in the periodic system of Mendeleyev. This metal melts at 937.4 ° C. The boiling point of this substance is 2700 ° C.
Germanium - the element that first becameapply in Japan for medical purposes. After numerous studies of organo-germanium compounds conducted on animals, as well as in human studies, it was possible to detect the positive effect of such ores on living organisms. In 1967, Dr. K. Asai managed to find out the fact that organic germanium has a huge range of biological effects.
What is the characteristic of the chemical elementGermany? He is able to carry oxygen to all tissues of a living organism. Getting into the blood, it behaves by analogy with hemoglobin. Germanium guarantees the full functioning of all systems of the human body.
It is this metal that stimulates the multiplication of immune cells. It, in the form of organic compounds, allows the formation of gamma-interferons, which suppress the reproduction of microbes.
Germanium prevents the formation of malignanttumors, does not allow the development of metastases. Organic compounds of this chemical element contribute to the production of interferon, a protective protein molecule, which is produced by the body as a protective reaction to the appearance of foreign bodies.
Areas of use
Antifungal, antibacterial,the antiviral property of germanium has become the basis of its application. In Germany, this element was mainly obtained as a by-product of processing of non-ferrous ores. In different ways, which depend on the composition of the feedstock, germanium concentrate was isolated. Its composition contained no more than 10 percent of the metal.
How exactly in the semiconductor moderntechnology applies germanium? The characteristic of the element given earlier confirms the possibility of its use for the production of triodes, diodes, power rectifiers, and crystal detectors. Also, germanium is used in the creation of dosimetric devices, devices that are necessary for measuring the strength of a constant and alternating magnetic field.
An essential field of application of this metal is the manufacture of infrared radiation detectors.
Perspective is the use not only of germanium itself, but also of some of its compounds.
Germanium at room temperature is pretty resistant to moisture and oxygen.
In the series of chemical elements (silicon-germanium-tin), an increase in the reducing ability is observed.
Germanium is resistant to the action of solutions of hydrochloric acidand sulfuric acids, it does not interact with alkali solutions. In this case, this metal dissolves rather quickly in aqua regia (seven nitric and hydrochloric acids), as well as in an alkaline solution of hydrogen peroxide.
How to give a complete description of the chemicalelement? Germanium and its alloys must be analyzed not only in terms of physical, chemical properties, but also fields of application. The process of oxidation of germanium with nitric acid proceeds slowly enough.
Being in nature
Let's try to characterize the chemicalelement. Germanium in nature is found only in the form of compounds. Among the most common germanium-containing minerals in nature, we distinguish germanite and argyrodite. In addition, germanium is present in sulphides and silicates of zinc, and in an insignificant amount it is present in various types of coal.
Harm to health
What effect does germanium have on the body? A chemical element, the electronic formula of which is of the form le; 8 e; 18 e; 7 e, can adversely affect the human body. For example, when loading germanium concentrate, grinding, as well as loading the dioxide of a given metal, occupational diseases may appear. As other sources that are harmful to health, we can consider the process of remelting germanium powder into bars, obtaining carbon monoxide.
Adsorbed germanium can be fast enoughremove from the body, mostly with urine. At present, there is no detailed information on how toxic the inorganic germanium compounds are.
Irritant effect on the skin rendersgermanium tetrachloride. In clinical trials, as well as long-term oral administration of cumulative quantities, which reached 16 grams of spirogermanium (an organic antitumor drug), as well as other germanium compounds, the nephrotoxic and neurotoxic activity of this metal was detected.
Such dosages are generally not characteristic ofindustrial enterprises. Those experiments that were conducted on animals were aimed at studying the action of germanium and its compounds on a living organism. As a result, it was possible to establish a deterioration in health by inhaling a significant amount of dust of metallic germanium, as well as its dioxide.
Scientists have found in the lungs of animals seriousmorphological changes, which are similar to proliferative processes. For example, there was a significant thickening of the alveolar sections, as well as hyperplasia of the lymph vessels around the bronchi, thickening of the blood vessels.
Dioxide of germanium does not irritateaction on the skin, but the direct contact of this compound with the skin of the eye leads to the formation of germanium acid, which is a serious eye irritant. With prolonged intraperitoneal injections, serious changes in peripheral blood were found.
The most harmful compounds of germanium arechloride and germanium hydride. The latter substance provokes serious poisoning. As a result of a morphological examination of the organs of animals that died in the acute phase, they showed significant disorders in the circulatory system, as well as cellular modifications in the parenchymal organs. Scientists came to the conclusion that the hydride is a multipurpose poison that affects the nervous system, depresses the peripheral circulation system.
It is a strong irritant of the respiratory system, eyes, skin. At a concentration of 13 mg / m3it is able to suppress at the cellular levelpulmonary response. With an increase in the concentration of this substance, severe irritation of the upper respiratory tract, significant changes in the rhythm and frequency of respiration are observed.
Poisoning with this substance leads to catarrhal and desquamative bronchitis, interstitial pneumonia.
Since in nature germanium is represented asimpurities to nickel, polymetallic, tungsten ores, for the isolation of pure metal in industry, several labor-intensive processes associated with ore dressing are carried out. First, the germanium oxide is isolated from it, then it is reduced by hydrogen at an elevated temperature to obtain a simple metal:
GeO2 + 2H2 = Ge + 2H2O.
Electronic properties and isotopes
Germanium is considered an indirectly typical semiconductor. The magnitude of its dielectric statistical permeability is 16, and the electron affinity is 4eV.
In a thin film of alloyed gallium, it is possible to impart a state of superconductivity to germanium.
In nature, there are five isotopes of this metal. Of these, four are stable, and the fifth is subjected to double beta decay, the half-life is 1.58 × 1021years.
At present, the organic compounds of thismetal are used in various industries. Transparency in the infrared spectral region of ultra-high purity metallic germanium is important for the fabrication of optical elements of infrared optics: prisms, lenses, optical windows of modern sensors. The most common area of use of germanium is the creation of optics for thermal imaging cameras that operate in the wavelength range from 8 to 14 microns.
Such devices are used in military equipmentfor infrared guidance systems, night vision, passive thermal imaging, fire protection systems. Also, germanium has a high refractive index, which is necessary for anti-reflective coating.
In radio engineering, transistors based on germaniumhave characteristics that in many respects exceed the performance of silicon elements. The reverse currents of the germanium elements are much higher than those of their silicon analogs, which makes it possible to substantially increase the efficiency of such radio devices. Given that germanium is not as common in nature as silicon, silicon semiconductor elements are mainly used in radio devices.