Characteristic of sulfur. Application of sulfur. Medical sera

Halcogens - a group of elements to which sulfur belongs. Her chemical sign - S - the first letter of the Latin name Sulfur. The composition of the simple substance is recorded using this symbol without an index. Consider the main points relating to the structure, properties, obtaining and applying this item. The sulfur characteristic will be presented as much as possible.

General features and differences in chalcogen

Sulfur refers to a subgroup of oxygen. This is the 16th group in the modern long-range form image of the periodic system (PS). Outdated version of the room and index - VIA. Names of group chemical elements, chemical signs:

• oxygen (o);
• sulfur (s);
• selenium (SE);
• tELLUR (TE);
• polonium (PO).

The outer electronic shell of the above elements is designed equally. In total, it contains 6 which can participate in the formation of a chemical bond with other atoms. Hydrogen compounds correspond to the composition H 2 R, for example, H 2 S is hydrogen sulfide. The names of the chemical elements forming with oxygen compounds of two types: sulfur, selenium and teleurur. General formulas of oxides of these elements - RO 2, RO 3.

Hallcohes correspond to simple substances that differ significantly in physical bonds. The most common in the earth's crust of all chalcogen - oxygen and sulfur. The first element forms two gas, the second - solids. Poloniy - a radioactive element - rarely found in the earth's crust. In group from oxygen to polonium, non-metallic properties decrease and metal increases. For example, sulfur is a typical nonmetall, and tellurium has metal glitter and electrical conductivity.

Element number 16 of the periodic system D.I. Mendeleev

The relative atomic mass of the sulfur - 32.064. Of the natural isotopes are the most common 32 s (more than 95% by weight). It is found in smaller amounts of nuclides with atomic mass 33, 34 and 36. Sulfur characteristics on the position in the PS and the structure of the atom:

• serial number - 16;
• atom nucleus charge is +16;
• atom radius - 0.104 nm;
• ionization energy -10.36 eV;
• relative electronegativity - 2.6;
• the degree of oxidation in compounds is +6, +4, +2, -2;
• valence - II (-), II (+), IV (+), Vi (+).

Sulfur is in the third period; Electrons in the atom are located on three energy levels: on the first - 2, on the second - 8, on the third - 6. The valences are all external electrons. When interacting with more electronegative elements, sulfur gives 4 or 6 electrons, acquiring the typical degrees of oxidation +6, +4. In reactions with hydrogen and metals, the atom attracts the missing 2 electron before filling the octet and achieving a stable state. In this case, it drops to -2.

Physical properties of rhombic and monoclinic allotropic forms

Under normal conditions, sulfur atoms are connected to each other at a stable circuit. They can be closed in the rings, which makes it possible to talk about the existence of cyclic sulfur molecules. Their composition reflects the formulas S 6 and S 8.

The characteristic of the sulfur should be supplemented with a description of the differences between allotropic modifications that have different physical properties.

Rhombic, or α-sulfur is the most stable crystalline form. These are bright yellow crystals consisting of molecules S 8. The density of rhombic sulfur is 2.07 g / cm3. The light yellow monoclinic crystals are formed by β-gray with a density of 1.96 g / cm3. Boiling point reaches 444.5 ° C.

Obtaining amorphous sulfur

What color sulfur in plastic state? It is a dark brown mass, absolutely not similar to yellow powder or crystals. To obtain it, you need to melt a rhombic or monoclinic sulfur. At temperatures above 110 ° C, liquid is formed, with further heating it darkens, at 200 ° C becomes thick and viscous. If you quickly pour the molten sulfur in cold water, it will freeze with the formation of zigzag chains, the composition of which reflects the formula S n.

Solubility of sulfur

Some modifications of the substance dissolve in the servo-carbon, benzene, toluene and liquid ammonia. If the organic solutions slowly cool, the needle crystals of monoclinic sulfur are formed. In evaporation of liquids, transparent lemon-yellow rhombic sulfur crystals are distinguished. They are fragile, they can easily grind them into powder. Sulfur does not dissolve in water. The crystals are lowered at the bottom of the vessel, and the powder can swim on the surface (not wetting).

Chemical properties

The reactions show typical non-metallic properties of element No. 16:

• sulfur oxidizes metals and hydrogen, restored to ion S 2-;
• when combustion in air and oxygen, di- and trioxides of sulfur are formed, which are anhydrides of acids;
• in the reaction with another more electronegative element - fluorine - sulfur also loses its electrons (oxidized).

Free sulfur

In the prevalence in the earth's crust, sulfur is 15th place among chemical elements. The average content of atoms S is 0.05% of the mass of the earth's crust.

What color is sulfur in nature (native)? This is a light yellow powder with a characteristic odor or yellow crystals with glass glitter. Deposits in the form of plants, crystal sulfur layers are found in areas of ancient and modern volcanism: in Italy, Poland, Central Asia, Japan, Mexico, USA. Often, during the extraction, beautiful dresses and giant single crystals are found.

Hydrogen sulfide and oxides in nature

In areas of volcanism, gaseous compounds of sulfur come to the surface. The Black Sea at a depth of more than 200 m is lifeless due to the release of hydrogen sulfide H 2 S. The formula of sulfur oxide bivalent - SO 2, trivalent - SO 3. The listed gaseous compounds are present as part of some fields of oil, gas, natural waters. Sulfur is part of coal. It is necessary for building many organic compounds. In the rotting of the chicken egg proteins, hydrogen sulfide is distinguished, so it is often said that this gas is smell of rotten eggs. Sulfur refers to biogenic elements, it is necessary for the growth and development of man, animals and plants.

The value of natural sulfides and sulfates

The characteristic of sulfur will be incomplete, if not to say that the element is found not only in the form of a simple substance and oxides. The most common natural compounds are salts of hydrogen sulfide and sulfuric acids. Sulfides of copper, iron, zinc, mercury, lead are found in the composition of minerals of chalcopyrite, pyrite, sphalerite, cycina and galvanit. Sulfates can be called sodium, calcium, barium and magnesium salts, which form in nature minerals and rocks (Mirable, Gypsum, Selenite, Barite, Kizaryit, Epsomit). All these compounds are used in different branches of the economy, used as raw materials for industrial processing, fertilizers, building materials. Great medical significance of some crystallohydrates.

Obtaining

The substance of yellow in a free state is found in nature at different depths. If necessary, sulfur is paid from rocks, without lifting them to the surface, and the penetrated overheated depth and one more method is associated with the sublimation of crushed rocks in special furnaces. Other methods provide for the dissolution of the servo-carbon or flotation.

The requirements of industry in sulfur are high, therefore its compounds are used to obtain an elementary substance. In hydrogen sulfide and sulfide sulfids are in restored form. The degree of oxidation of the element is -2. Sulfur is carried out, increasing this value to 0. For example, according to the method of Leblan, sodium sulfate is restored to the coal to the sulfide. Then the calcium sulphide is obtained from it, it is treated with carbon dioxide and water vapor. The resulting hydrogen sulfide is oxidized by air oxygen in the presence of a catalyst: 2H 2 S + O 2 \u003d 2H 2 O + 2S. The definition of sulfur, obtained by different ways, sometimes gives low purity. Refined or purification is carried out by distillation, distillation, processing of mixtures of acids.

The use of sulfur in the modern industry

Sulfur granulated goes to various production needs:

1. Obtaining sulfuric acid in the chemical industry.
2. Production of sulfite and sulfates.
3. Release of drugs for filtering plants, combating diseases and pests of crops.
4. Serio-containing ores at mining and chemical combines are processed to obtain non-ferrous metals. The concomitant production is sulfuric acid.
5. Introduction to some varieties of steels to give special properties.
6. Thanks to the volcanization of rubber get rubber.
7. Production of matches, pyrotechnics, explosives.
8. Use for the preparation of paints, pigments, artificial fibers.
9. Whitening of fabrics.

Sulfur toxicity and its compounds

Dusty particles with an unpleasant smell are irritated to the mucous membranes of the nasal cavity and respiratory tract, eyes, skin. But the toxicity of elementary sulfur is considered not particularly high. Inhalation of hydrogen sulfide and dioxide can cause severe poisoning.

If under the firing of sulfur-containing ores at the metallurgical plants, the exhaust gases are not captured, they come to the atmosphere. Connecting with drops and vapors of water, sulfur and nitrogen oxides give the beginning of the so-called acid rain.

Sulfur and its compounds in agriculture

Plants absorb sulfate ions along with soil solution. Reducing the sulfur content leads to a slowdown in the metabolism of amino acids and proteins in green cells. Therefore, sulfates are used for agricultural crops.

For disinfection of poultry houses, basements, vegetable stores, a simple substance burns or process rooms with modern sulfur-containing drugs. Sulfur oxide has antimicrobial properties that it has long been used in the production of wines, when storing vegetables and fruits. Sulfur preparations are used as pesticides to combat diseases and pests of crops (powdery dew and spider ticks).

Application in medicine

Large importance to the study of therapeutic properties of a yellow powder was given the great healers of antiquity of Avicenna and Paracels. It was later established that a person who does not receive a sufficient amount of sulfur with food, weakens, has health problems (they include itching and skin peeling, weakening hair and nails). The fact is that the synthesis of amino acids, keratin, biochemical processes in the body is disturbed without sulfur.

Medical sulfur is included in the composition of ointments for the treatment of skin diseases: acne, eczema, psoriasis, allergies, seborrhea. Baths with sulfur can ease pain in rheumatism and gout. For better assimction, water-soluble sulfur-containing drugs have been created. This is not a yellow powder, but a small-crystalline substance of white. With the external use of this compound, it is introduced into the composition of the cosmetic skin care.

Gypsum has long been used when immobilizing the injured parts of the human body. prescribe as a laxative medicine. Magnesia lowers blood pressure, which is used in the treatment of hypertension.

Sulfur in history

Even in ancient times, the non-metallic substance of yellow attracted the attention of a person. But only in 1789, the great chemist of Lavoisier found that the powder and crystals found in nature consist of sulfur atoms. It was believed that the unpleasant smell arising from its burning, scares all evil. The formula of sulfur oxide, which is obtained by burning - SO 2 (dioxide). It is toxic gas, its inhalation is dangerous to health. Several cases of mass extinction of people with whole villages on the coasts, in lowlands, scientists explain from the Earth or the water of hydrogen sulfide or sulfur dioxide.

The invention of black powder has increased interest in yellow crystals from the military. Many battles have been won due to the skill of masters to connect sulfur with other substances in the manufacturing process. The most important connection is sulfuric acid - also learned to apply for a very long time. In the Middle Ages, this substance was called civil oil, and salts are vitriors. Copper Custo 4 and the FESO 4 Iron Courtyard have not yet lost its importance in industry and agriculture.