home > Foreign > History of sulfur chemistry. Pure yellow sulfur


History of sulfur chemistry. Pure yellow sulfur




Sulfur is a substance that is in the table in group 16, under the third period and has an atomic number of 16. It can occur both in native and in bound form. Sulfur is denoted by the letter S. Known sulfur formula– (Ne)3s 2 3p 4 . Sulfur as an element included in many proteins.

If speak about the structure of the atom of the element sulfur, then there are electrons in its outer orbit, the valence number of which reaches six.

This explains the element's property of being maximally hexavalent in most unions. There are four isotopes in the structure of a natural chemical element, and these are 32S, 33S, 34S and 36S. Speaking of the outer electron shell, the atom has a 3s2 3p4 scheme. The radius of an atom is 0.104 nanometers.

Sulfur properties primarily divided into physical type. It refers to the fact that the element has a solid crystalline composition. Two allotropic modifications are the main state in which this sulfur element is stable.

The first modification is rhombic, having a lemon-yellow color. Its stability is lower than 95.6 °C. The second is monoclinic, having a honey-yellow color. Its stability ranges from 95.6 °C and 119.3 °C.

In the photo, the sulfur mineral

During melting, the chemical element becomes a moving liquid that has a yellow color. It turns brown, reaching a temperature of more than 160 ° C. And at 190 °C sulfur color turns to dark brown. After reaching 190 °C, a decrease in the viscosity of the substance is observed, which, however, after heating to 300 °C, becomes fluid.

Other properties of sulfur:

  • Practically does not conduct heat and electricity.
  • Does not dissolve when immersed in water.
  • Soluble in ammonia, which has an anhydrous structure.
  • It is also soluble in carbon disulfide and other organic solvents.

To characteristics of the element sulfur it is important to add its chemical features. She is active in this regard. If sulfur is heated, it can simply combine with almost any chemical element.

The photo shows a sulfur sample mined in Uzbekistan

Except for inert gases. In contact with metals, chem. the element forms sulfides. Room temperature encourages the element to react with. Increased temperature increases the activity of sulfur.

Consider how the behavior of sulfur with individual substances:

  • With metals - is an oxidizing agent. Forms sulfides.
  • With hydrogen - at high temperatures - up to 200 ° C, an active interaction occurs.
  • With oxygen. Combinations of oxides are formed at temperatures up to 280 °C.
  • With phosphorus, carbon - is an oxidizing agent. Only in the absence of air during the reaction.
  • With fluorine - manifests itself as a reducing agent.
  • With substances having a complex structure - also as a reducing agent.

Deposits and production

The main source for obtaining sulfur is its deposits. In general, there are 1.4 billion tons of reserves of this substance all over the world. It is mined both by open and underground mining methods, and by smelting from underground.

Sulfur mining in Kawa Ijen volcano

If the latter case applies, then water is used, which is superheated and sulfur is melted with it. In poor ores, the element is contained in approximately 12%. The rich - 25% or more.

Common types of deposits:

  1. Stratiform - up to 60%.
  2. Salt dome - up to 35%.
  3. Volcanogenic - up to 5%.

The first type is associated with strata bearing the name sulfate-carbonate. At the same time, ore bodies that have a thickness of up to several tens of meters and with a size of up to hundreds of meters are located in sulfate rocks.

Also, these reservoir deposits can be found among rocks of sulfate and carbonate origin. The second type is characterized by gray deposits, which are confined to salt domes.

The latter type is associated with volcanoes that have a young and modern structure. In this case, the ore element has a sheet-like, lenticular shape. It may contain sulfur in the amount of 40%. This type of deposit is common in the Pacific volcanic belt.

Sulfur deposit in Eurasia is located in Turkmenistan, in the Volga region and other places. Sulfur rocks are found near the left banks of the Volga, which stretch from Samara. The width of the rock band reaches several kilometers. At the same time, they can be found right up to Kazan.

Sulfur crystals can have different shades of yellow

In the photo, sulfur in the rock

In Texas and Louisiana, huge amounts of sulfur are found in the roofs of salt domes. Especially beautiful Italians of this element are found in Romagna and Sicily. And on the island of Vulcano they find monoclinic sulfur. An element that was oxidized with pyrite was found in the Urals in the Chelyabinsk region.

For prey sulfur chemical element use different methods. It all depends on the condition of its occurrence. At the same time, of course, special attention is paid to safety.

Since hydrogen sulfide accumulates along with sulfur ore, it is necessary to take any method of extraction very seriously, because this gas is poisonous to humans. Sulfur also tends to ignite.

Most often they use the open method. So with the help of excavators, significant parts of the rocks are removed. Then, with the help of explosions, the ore part is crushed. Lumps are sent to the factory for enrichment. Then - to the sulfur smelting plant, where sulfur is obtained from the concentrate.

Sulfur is often transported by sea

In the case of deep sulfur deposits in many volumes, the Frasch method is used. Sulfur melts while still underground. Then, like oil, it is pumped out through a punched well. This approach is based on the fact that the element melts easily and has a low density.

Also known is a method of separation in centrifuges. Only this method has a drawback: sulfur is obtained with impurities. And then it is necessary to carry out its additional cleaning.

In some cases, the borehole method is used. Other opportunities for mining sulfur element:

  • Steam water.
  • Filtration.
  • Thermal.
  • Centrifugal.
  • Extractive.

Sulfur application

Most of the sulfur that is mined goes to make sulfuric acid. And the role of this substance is very huge in chemical production. It is noteworthy that to obtain 1 ton of sulfur matter, 300 kg of sulfur are needed.

Bengal lights, which glow brightly and have many dyes, are also made using sulfur. The paper industry is another area where a significant part of the mined substance goes.

Sulfur ointment is used to treat skin diseases

Most often sulfur application finds when meeting production needs. Here is some of them:

  • Use in chemical production.
  • For the manufacture of sulfites, sulfates.
  • Manufacture of substances for plant fertilizers.
  • To get non-ferrous types of metals.
  • To give steel additional properties.
  • For the manufacture of matches, materials for explosions and pyrotechnics.
  • Paints, fibers from artificial materials - are made using this element.
  • For fabric bleaching.

In some cases sulfur element included in ointments that treat skin diseases.

Sulfur price

According to the latest news, the need for sulfur is actively growing. The cost of a Russian product is $130. For the Canadian version - $ 145. But in the Middle East, prices have risen to $8, resulting in a cost of $149.

The photo shows a large specimen of the sulfur mineral

In pharmacies, you can find sulfur in powdered hammer at a price of 10 to 30 rubles. In addition, it is possible to buy it in bulk. Some organizations offer at a low price to purchase granular technical gas sulfur.

Sulfur is one of the most important trace elements for humans, responsible for the good appearance of the nail plates, strands, and skin. This element is present in the composition of medicinal and cosmetic preparations; a properly composed diet will help to avoid deficiency.

Sulfur is an essential element for the human body

What is sulfur

Sulfur is an essential element of all protein compounds in the human body, it is involved in the processes of metabolism and regeneration, its benefits and effects on health can hardly be overestimated.

What is sulfur for?

  • creation of cells, cartilage and bones, collagen synthesis;
  • responsible for the appearance of nails and strands, a healthy complexion, prevents the appearance of wrinkles;
  • ear wax protects the hearing organs from infections, cleans them from dust and dirt;
  • the element is part of amino acids, some hormones, enzymes, is required for good blood clotting;
  • maintains oxygen balance, sugar level.

Through the skin, sulfur penetrates into the deeper layers, breaks down into sulfates and sulfites, enters the bloodstream, spreads to all internal organs, but it is also necessary to take it inside. The substance is excreted from the body through the kidneys.

Useful properties of sulfur

Sulfur is used for medicinal and cosmetic purposes. The main task of sulfur is anti-allergic and immunomodulatory action, improving the functioning of the nervous system, cleansing the body of toxic elements and toxins.

The effect of sulfur on the body:

  • protects against pathogens;
  • maintains the required level of bile, which contributes to better absorption of food;
  • protects cells from the negative effects of radiation and other harmful external factors;
  • stops the development of articular pathologies;
  • prevents the development of anemia, ensures a normal supply of oxygen to the tissues.

Sulfur interacts with vitamins of group B, H, lipoic acid, provides energy to brain cells, promotes better absorption of glucose by muscles.

Sulfur maintains normal levels of bile in the body

Where applicable

Pharmaceutical sulfur is used to treat various diseases, medicines based on this trace element can quickly eliminate the manifestation of articular and dermatological pathologies.

What helps sulfur:

  • allergies and dermatological diseases;
  • bronchial asthma;
  • arthritis, scoliosis, bursitis, osteoarthritis, myositis, sprains;
  • convulsions;
  • as an anti-inflammatory and analgesic;
  • to strengthen the immune system, speedy recovery after prolonged illness;
  • to reduce the body's need for insulin in diabetes mellitus.

In cosmetology, products with sulfur are used to prevent early aging, improve the appearance of the skin, give strength and shine to the hair, and strengthen the nail plates.

Sulfur is used in cosmetology

For external medicinal preparations, precipitated (purified, combustible) sulfur is practiced, it is part of the sulfur ointment, which is prescribed for the treatment of scabies, seborrhea, psoriasis. In combination with lanolin, petroleum jelly, stearic acid, the microelement has an antihelminthic, exfoliating and anti-inflammatory effect - such drugs are prescribed to eliminate rosacea, we deprive the scalp of lesions.

Purified sulfur in the form of tablets is used in the treatment of enterobiasis, constipation, as an external agent for the treatment of dermatological pathologies. In the form of a yellow powder, the product is used in folk and traditional medicine, it can be used orally, to prepare medicines.

Homeopathic sulfur has a mild therapeutic effect, it is produced in the form of granules, you need to take the drug for a long time under the supervision of a specialist.

Sulfur is useful not only for people, but also for animals - the feed product is included in the composition of vitamins for animals. This trace element is also used to enrich fertilizers in agriculture, in the production of steel and rubber, explosives, and pyrotechnics.

What foods contain sulfur

The daily requirement for sulfur is 0.5–1.2 g, with a balanced menu, the presence of a sufficient amount of protein foods in the diet, the required amount can be obtained daily from food. Most of it is found in products of animal origin, in small quantities it can be found in plant foods.

Table of foods high in sulfur

Product Sulfur content (mg)
Rabbit meat, chicken, turkey180–240
Pike, perch, sardine, pink salmon, flounder190–210
Soya240–250
Green peas180–190
Raw hazelnuts, almonds170–190
chicken eggs170–180
Quail eggs120–130
Condensed milk70–75
Barley, wheat, oatmeal70–100
Onion60–70
Rice, semolina60–70
Milk30–35
cabbage, potatoes30–40
Tomatoes, eggplant12–15
Raspberry, strawberry, gooseberry12–18
Melon, citrus fruit10–12

An increased amount of sulfur up to 3 g per day is required for excessive physical and mental stress, for adolescents during a period of intensive growth, for athletes.

Instructions for the use of sulfur

Before using sulfur-containing drugs, you should always consult with a specialist. Only a doctor can choose the optimal and safe dosage of the drug.

Sulfuric ointment

Sulfuric ointment should be applied 1-3 times a day on dry, cleansed skin, the duration of treatment is 5-10 days.

Sulfur powder for internal use

Purified sulfur in the form of a powder helps with enterobiasis, obesity, problems with hematopoiesis, a precipitated product can also be used, but it often provokes the development of flatulence.

Medical sulfur should be taken with food

Sulfur is best absorbed when combined with iron and fluorine. Barium, lead, selenium, molybdenum reduce the percentage of trace element absorption.

In the pharmacy you can buy vitamin nutritional supplements based on yeast and sulfur - Evisent, AMT, Bioterra, they contain all the necessary elements to improve the condition of hair, nails, to rejuvenate the skin of the face, and maintain health.

Indications for use:

  • manifestations of a lack of vitamins of group B;
  • recovery period after surgery and prolonged illness;
  • depletion of the body, passion for strict diets;
  • endocrine pathologies - diabetes mellitus, thyroid disorders, obesity, hormonal imbalance;
  • diseases of the digestive system, deterioration of blood clotting;
  • nervous, physical, mental overwork;
  • for the prevention of cardiovascular diseases;
  • dermatological diseases - acne, acne, furunculosis.

Brewer's yeast with sulfur improves skin, hair and nails

Tablets should be taken in 6-15 pcs. daily in 3 doses for 2-3 months, after which you need to take a break for six months.

Sulfur-based preparations are contraindicated during pregnancy and lactation, they are not used for the treatment of children under three years of age.

At the initial stage of using sulfur-based preparations, rashes may appear, the skin begins to peel off strongly, sometimes a laxative effect is observed - these are not side reactions, such a reaction is provoked by the strong antiseptic and anti-inflammatory properties of the microelement, all pathogenic microorganisms are drawn out through the skin.

Natural alternative to chewing gums, completely composed of resinous larch compounds, has an antimicrobial effect. Chewing sulfur returns the natural color of tooth enamel, prevents the development of caries, periodontal disease, periodontitis, inflammation in the oral cavity, helps to cope with toothache, is indispensable for stomatitis, tonsillitis. Experts recommend chewing sulfur twice a day for 30 minutes.

Larch gum helps to quit smoking, avoid overeating.

Chewing sulfur helps to get rid of diseases of the oral cavity

Sulfur in folk medicine

Sulfur helps to get rid of colic, prevent hernia in children - the powder on the tip of the knife should be added to milk or other food. You must first consult with a surgeon or.

  1. Purified sulfur powder is taken 1 g three times a day for dermatological problems. For the treatment of diathesis in children, you can prepare an ointment from an equal amount of sulfur and fatty sour cream, lubricate the affected areas 1-2 times a day after water procedures. The mixture can be used even for newborns after prior consultation with a pediatrician.
  2. The recipe for a universal talker to eliminate inflammatory processes on the face is to combine 50 ml of boric acid with ethyl alcohol, add 7 g of medical sulfur, 1 tablet of acetylsalicylic acid. Shake, pour into a dark glass container, store in the refrigerator, wipe the inflamed areas in the morning and evening.

Sour cream and sulfur are well suited for the treatment of skin diseases in children.

What are the dangers of a lack or excess of sulfur

Excess and deficiency of sulfur are rarely observed in the body. People who consume little protein suffer from a lack of microelements, an overabundance may indicate a violation of metabolic processes.

With a lack of sulfur, hypertension, tachycardia develops, the skin becomes dry, begins to peel off, the hair loses its shine, the nails exfoliate, and the liver deteriorates. The lack of an element is evidenced by frequent allergic reactions, increased sugar levels, joint and muscle pain, and constipation.

Signs of an excess of sulfur:

  • the skin becomes oily, acne, itching appear;
  • photophobia, increased lacrimation, frequent conjunctivitis, sensation of the presence of a foreign body in the eyes;
  • increased fatigue, migraine;
  • loss of appetite, nausea, disturbances in the digestive system;
  • bronchitis with symptoms of asthma;
  • decrease in hemoglobin level.

With an excess of sulfur, acne appears and the skin becomes oily.

The accumulation of sulfur does not occur with excessive consumption of foods that are rich in this trace element. Poisoning is possible only with prolonged contact with sulfur dioxide, hydrogen sulfide.

An excess of sulfur can lead to the development of serious mental pathologies, seizures, and in case of severe poisoning, loss of consciousness is possible.

Sulfur is an essential trace element for beauty and good health. You can get it with food, and in case of serious diseases, you can buy sulfur powder, ointments or tablets based on it at the pharmacy. Lack and excess of the element manifest itself in the form of various pathologies.

Pure yellow sulfur

A mineral from the class of native elements. Sulfur is an example of a well-defined enantiomorphic polymorphism. In nature, it forms 2 polymorphic modifications: rhombic a-sulfur and monoclinic b-sulfur. At atmospheric pressure and a temperature of 95.6°C, a-sulfur transforms into b-sulfur. Sulfur is vital for the growth of plants and animals, it is part of living organisms and their decomposition products, it is abundant, for example, in eggs, cabbage, horseradish, garlic, mustard, onions, hair, wool, etc. It is also present in coals and oil.

See also:

STRUCTURE

Native sulfur is usually represented by a-sulfur, which crystallizes in a rhombic syngony, rhombo-dipyramidal symmetry. Crystalline sulfur has two modifications; one of them, rhombic, is obtained from a solution of sulfur in carbon disulfide (CS 2) by evaporation of the solvent at room temperature. In this case, diamond-shaped translucent crystals of light yellow color are formed, easily soluble in CS 2 . This modification is stable up to 96°C; at higher temperatures, the monoclinic form is stable. During natural cooling of molten sulfur in cylindrical crucibles, large crystals of rhombic modification with a distorted shape grow (octahedrons, in which corners or faces are partially “cut off”). Such material is called lump sulfur in the industry. Monoclinic modification of sulfur is a long transparent dark yellow needle-shaped crystals, also soluble in CS 2 . When monoclinic sulfur is cooled below 96 ° C, a more stable yellow rhombic sulfur is formed.

PROPERTIES

Native sulfur is yellow, in the presence of impurities - yellow-brown, orange, brown to black; contains inclusions of bitumen, carbonates, sulfates, clay. Crystals of pure sulfur are transparent or translucent, solid masses are translucent at the edges. The luster is resinous to greasy. Hardness 1-2, no cleavage, conchoidal fracture. Density 2.05 -2.08 g / cm 3, fragile. Easily soluble in Canadian balsam, turpentine and kerosene. In HCl and H 2 SO 4 it is insoluble. HNO 3 and aqua regia oxidize sulfur, turning it into H 2 SO 4. Sulfur differs significantly from oxygen in its ability to form stable chains and cycles of atoms.
The most stable are cyclic molecules S 8 having the shape of a crown, forming rhombic and monoclinic sulfur. This is crystalline sulfur - a brittle yellow substance. In addition, molecules with closed (S 4 , S 6 ) chains and open chains are possible. Such a composition has plastic sulfur, a brown substance, which is obtained by sharp cooling of the sulfur melt (plastic sulfur becomes brittle after a few hours, acquires a yellow color and gradually turns into a rhombic one). The formula for sulfur is most often written simply as S, since, although it has a molecular structure, it is a mixture of simple substances with different molecules.
The melting of sulfur is accompanied by a noticeable increase in volume (about 15%). Molten sulfur is a yellow, highly mobile liquid, which above 160 °C turns into a very viscous dark brown mass. The sulfur melt acquires the highest viscosity at a temperature of 190 °C; a further increase in temperature is accompanied by a decrease in viscosity, and above 300 °C the molten sulfur becomes mobile again. This is due to the fact that when sulfur is heated, it gradually polymerizes, increasing the chain length with increasing temperature. When sulfur is heated above 190 °C, the polymer units begin to break down.
Sulfur is the simplest example of an electret. When rubbed, sulfur acquires a strong negative charge.

MORPHOLOGY

It forms truncated-dipyramidal, rarely dipyramidal, pinacoidal or thick-prismatic crystals, as well as dense cryptocrystalline, confluent, granular, less often fine-fibred aggregates. The main forms on the crystals: dipyramids (111) and (113), prisms (011) and (101), pinacoid (001). Also intergrowths and druses of crystals, skeletal crystals, pseudostalactites, powdery and earthy masses, raids and smears. Crystals are characterized by multiple parallel intergrowths.

ORIGIN

Sulfur is formed during volcanic eruptions, during the weathering of sulfides, during the decomposition of gypsum-bearing sedimentary strata, and also in connection with the activity of bacteria. The main types of native sulfur deposits are volcanogenic and exogenous (chemogenic-sedimentary). Exogenous deposits predominate; they are associated with gypsum anhydrites, which, under the influence of hydrocarbon and hydrogen sulfide emissions, are reduced and replaced by sulfur-calcite ores. All the largest deposits have this infiltration-metasomatic genesis. Native sulfur is often formed (except for large accumulations) as a result of the oxidation of H 2 S. The geochemical processes of its formation are significantly activated by microorganisms (sulfate-reducing and thionic bacteria). Associated minerals are calcite, aragonite, gypsum, anhydrite, celestite, and sometimes bitumen. Among volcanic deposits of native sulfur, hydrothermal-metasomatic (for example, in Japan), formed by sulfur-bearing quartzites and opalites, and volcanogenic-sedimentary sulfur-bearing silts of crater lakes are of primary importance. It is also formed during fumarole activity. Being formed under the conditions of the earth's surface, native sulfur is still not very stable and, gradually oxidizing, gives rise to sulfates, Ch. like plaster.
Used in the production of sulfuric acid (about 50% of the extracted amount). In 1890, Hermann Frasch suggested melting sulfur underground and extracting it to the surface through wells, and at present sulfur deposits are being developed mainly by smelting native sulfur from underground layers directly in places of its occurrence. Sulfur is also found in large quantities in natural gas (in the form of hydrogen sulfide and sulfur dioxide), during gas production it is deposited on the walls of pipes, putting them out of action, so it is captured from the gas as soon as possible after production.

APPLICATION

Approximately half of the sulfur produced is used in the production of sulfuric acid. Sulfur is used to vulcanize rubber, as a fungicide in agriculture, and as colloidal sulfur - a drug. Also, sulfur in the composition of sulfur-bitumen compositions is used to obtain sulfur asphalt, and as a substitute for Portland cement - to obtain sulfur concrete. Sulfur is used in the production of pyrotechnic compositions, was previously used in the production of gunpowder, and is used in the production of matches.

Sulfur - S

CLASSIFICATION

Strunz (8th edition) 1/B.03-10
Nickel-Strunz (10th edition) 1.CC.05
Dana (7th edition) 1.3.4.1
Dana (8th edition) 1.3.5.1
Hey's CIM Ref. 1.51

Sulfur in its native state, as well as in the form of sulfur compounds, has been known since ancient times. It is mentioned in the Bible, the poems of Homer and others. Sulfur was part of the "sacred" incense during religious rites; the smell of burning Sulfur was believed to ward off evil spirits. Sulfur has long been a necessary component of incendiary mixtures for military purposes, such as "Greek fire" (10th century AD). Around the 8th century, sulfur began to be used in China for pyrotechnic purposes. Sulfur and its compounds have long been used to treat skin diseases. During the period of Arabic alchemy, a hypothesis arose according to which Sulfur (the beginning of combustibility) and mercury (the beginning of metallicity) were considered constituents of all metals. The elementary nature of Sulfur was established by A. L. Lavoisier and included in the list of non-metallic simple bodies (1789). In 1822, E. Mitscherlich discovered the allotropy of Sulfur.

Distribution of sulfur in nature. Sulfur is a very common chemical element (clarke 4.7 10 -2); occurs in the free state (native sulfur) and in the form of compounds - sulfides, polysulfides, sulfates. The water of the seas and oceans contains sulfates of sodium, magnesium, calcium. More than 200 sulfur minerals are known to be formed during endogenous processes. More than 150 sulfur minerals (mainly sulfates) are formed in the biosphere; processes of oxidation of sulfides to sulfates, which in turn are reduced to secondary H 2 S and sulfides, are widespread. These reactions occur with the participation of microorganisms. Many processes in the biosphere lead to the concentration of Sulfur - it accumulates in the humus of soils, coals, oil, seas and oceans (8.9·10 -2%), groundwater, lakes and salt marshes. In clays and shales, there is 6 times more sulfur than in the earth's crust as a whole, in gypsum - 200 times, in underground sulfate waters - dozens of times. Sulfur cycles in the biosphere: it is brought to the continents with precipitation and returned to the ocean with runoff. The source of Sulfur in the geological past of the Earth was mainly the products of volcanic eruptions containing SO 2 and H 2 S. Human economic activity accelerated the migration of Sulfur; the oxidation of sulfides intensified.

Physical properties of Sulfur. Sulfur is a solid crystalline substance, stable in the form of two allotropic modifications. Rhombic α-S lemon yellow, density 2.07 g/cm 3 , t pl 112.8 °C, stable below 95.6 °C; monoclinic β-S, honey yellow, density 1.96 g/cm 3 , melting point 119.3 °C, stable between 95.6 °C and melting point. Both of these forms are formed by eight-membered cyclic molecules S 8 with an S-S bond energy of 225.7 kJ/mol.

When melted, sulfur turns into a mobile yellow liquid, which turns brown above 160 °C, and becomes a viscous dark brown mass at about 190 °C. Above 190 °C, the viscosity decreases, and at 300 °C, sulfur again becomes fluid. This is due to a change in the structure of molecules: at 160 ° C, the S 8 rings begin to break, turning into open chains; Further heating above 190°C reduces the average length of such chains.

If molten Sulfur, heated to 250-300 °C, is poured into cold water in a thin stream, then a brown-yellow elastic mass (plastic Sulfur) is obtained. It only partially dissolves in carbon disulfide, leaving a loose powder in the sediment. Soluble in CS 2 modification is called λ-S, and insoluble - μ-S. At room temperature, both of these modifications are converted into stable brittle α-S. bale t Sulfur 444.6 ° C (one of the standard points of the international temperature scale). In vapors at the boiling point, in addition to S 8 molecules, there are also S 6 , S 4 and S 2 . With further heating, large molecules break up, and at 900 °C only S 2 remains, which at approximately 1500 °C noticeably dissociate into atoms. When liquid nitrogen freezes strongly heated sulfur vapors, a purple modification, stable below -80 °C, formed by S 2 molecules, is obtained.

Sulfur is a poor conductor of heat and electricity. It is practically insoluble in water, readily soluble in anhydrous ammonia, carbon disulfide and a number of organic solvents (phenol, benzene, dichloroethane, and others).

Chemical properties of Sulfur. The configuration of the outer electrons of the atom S 3s 2 Зр 4 . In compounds, Sulfur exhibits oxidation states -2, +4, +6. Sulfur is chemically active and combines especially easily with almost all elements when heated, with the exception of N 2 , I 2 , Au, Pt and inert gases. C O 2 in air above 300 ° C forms oxides: SO 2 - sulfurous anhydride and SO 3 - sulfuric anhydride, from which sulfurous acid and sulfuric acid are obtained, respectively, as well as their salts sulfites and sulfates. Already in the cold, S vigorously combines with F 2, when heated, it reacts with Cl 2; with bromine Sulfur forms only S 2 Br 2 , sulfur iodides are unstable. When heated (150-200 ° C), a reversible reaction with H 2 occurs to produce hydrogen sulfide. Sulfur also forms polysulphurous hydrogens of the general formula H 2 S X, the so-called sulfanes. Numerous organosulfur compounds are known.

When heated, sulfur interacts with metals, forming the corresponding sulfur compounds (sulfides) and polysulfur metals (polysulfides). At a temperature of 800-900 °C, sulfur vapor reacts with carbon, forming carbon disulfide CS 2 . Sulfur compounds with nitrogen (N 4 S 4 and N 2 S 5) can only be obtained indirectly.

Getting Sulfur. Elemental sulfur is obtained from native sulfur, as well as by the oxidation of hydrogen sulfide and the reduction of sulfur dioxide. The source of hydrogen sulfide for the production of Sulfur is coke, natural gases, oil cracking gases. Numerous methods have been developed for processing H 2 S; the following are of greatest importance: 1) H 2 S is extracted from gases with a solution of sodium monohydrothioarsenate:

Na 2 HAsS 2 O 2 + H 2 S \u003d Na 2 HAsS 3 O + H 2 O.

Then, by blowing air through the solution, sulfur is precipitated in free form:

NaHAsS 3 O + ½O 2 \u003d Na 2 HAsS 2 O 2 + S.

2) H 2 S is isolated from gases in a concentrated form. Then its main mass is oxidized by atmospheric oxygen to Sulfur and partially to SO 2 . After cooling, H 2 S and the resulting gases (SO 2, N 2, CO 2) enter two successive converters, where in the presence of a catalyst (activated bauxite or specially manufactured aluminum gel) the following reaction occurs:

2H 2 S + SO 2 \u003d 3S + 2H 2 O.

The production of sulfur from SO 2 is based on the reaction of its reduction with coal or natural hydrocarbon gases. Sometimes this production is combined with the processing of pyrite ores.

Sulfur varieties. Smelted directly from sulfur ores Sulfur is called natural lump; obtained from H 2S and SO 2 - gas lump. Natural lump sulfur, purified by distillation, is called refined.

Condensed from vapors at a temperature above the melting point in a liquid state and then poured into molds - cutting sulfur. When Sulfur condenses below the melting point, a fine powder of Sulfur is formed on the walls of the condensation chambers - a sulfur color. Especially highly dispersed sulfur is called colloidal.

Use of Sulfur. Sulfur is used primarily to produce sulfuric acid; in the paper industry (for the production of sulfite cellulose); in agriculture (to combat plant diseases, mainly grapes and cotton); in the rubber industry (vulcanizing agent); in the production of dyes and luminous compositions; to obtain black (hunting) gunpowder; in the manufacture of matches.

Sulfur in the body. Sulfur is constantly present in all living organisms in the form of organic and inorganic compounds and is an important biogenic element. Its average content in terms of dry matter is: in marine plants about 1.2%, terrestrial - 0.3%, in marine animals 0.5-2%, terrestrial - 0.5%. The biological role of Sulfur is determined by the fact that it is part of compounds widely distributed in nature: amino acids (methionine, cysteine), and hence proteins and peptides; coenzymes (coenzyme A, lipoic acid), vitamins (biotin, thiamine), glutathione and others. Sulfhydryl groups (-SH) of cysteine ​​residues play an important role in the structure and catalytic activity of many enzymes. Forming disulfide bonds (-S-S-) within individual polypeptide chains and between them, these groups are involved in maintaining the spatial structure of protein molecules. Sulfur is also found in animals in the form of organic sulfates and sulfonic acids - chondroitinsulfuric acid (in cartilage and bones), taurocholic acid (in bile), heparin, and taurine. In some iron-containing proteins (for example, ferrodoxins), sulfur is found in the form of an acid-labile sulfide. Sulfur is capable of forming energy-rich bonds in macroergic compounds.

Inorganic sulfur compounds in the organisms of higher animals are found in small amounts, mainly in the form of sulfates (in the blood, urine), as well as thiocyanates (in saliva, gastric juice, milk, urine). Marine organisms are richer in inorganic sulfur compounds than freshwater and terrestrial ones. For plants and many microorganisms, sulfate (SO 4 2-), along with phosphate and nitrate, is the most important source of mineral nutrition. Before incorporation into organic compounds, Sulfur undergoes a change in valency and is then converted to organic form in its least oxidized state; thus Sulfur is widely involved in redox reactions in cells.

In cells, sulfates, interacting with adenosine triphosphate (ATP), are converted into an active form - adenyl sulfate.

The enzyme catalyzing this reaction, sulfurylase (ATP:sulfate-adenylyltransferase), is widely distributed in nature. In such an activated form, the sulfonyl group undergoes further transformations - it is transferred to another acceptor or reduced.

Animals assimilate Sulfur as part of organic compounds. Autotrophic organisms obtain all the Sulfur contained in cells from inorganic compounds, mainly in the form of sulfates. Higher plants, many algae, fungi and bacteria are capable of autotrophic assimilation of sulfur. (A special protein was isolated from a culture of bacteria, which transfers sulfate through the cell membrane from the environment into the cell.) An important role in the sulfur cycle in nature is played by microorganisms - desulfurizing bacteria and sulfur bacteria. Many developed sulfur deposits are of biogenic origin. Sulfur is a part of antibiotics (penicillins, cephalosporins); its compounds are used as radioprotective agents, plant protection agents.

The content of the article

SULFUR, S (sulfur), a non-metallic chemical element, a member of the chalcogen family (O, S, Se, Te and Po) - Group VI of the Periodic Table of Elements. Sulfur, like many of its uses, has been known since ancient times. A. Lavoisier argued that sulfur is an element. Sulfur is vital for the growth of plants and animals, it is part of living organisms and their decomposition products, it is abundant, for example, in eggs, cabbage, horseradish, garlic, mustard, onions, hair, wool, etc. It is also present in coals and oil.

Application.

About half of the annual consumption of sulfur goes to the production of industrial chemicals such as sulfuric acid, sulfur dioxide and carbon disulphide (carbon disulphide). In addition, sulfur is widely used in the production of insecticides, matches, fertilizers, explosives, paper, polymers, paints and dyes, and in the vulcanization of rubber. The leading place in the production of sulfur is occupied by the USA, the CIS countries and Canada.

distribution in nature.

Sulfur occurs in a free state (native sulfur). In addition, there are huge reserves of sulfur in the form of sulfide ores, primarily ores of lead (lead sheen), zinc (zinc blende), copper (copper sheen), and iron (pyrite). When metals are extracted from these ores, sulfur is usually removed by roasting in the presence of oxygen, which produces sulfur (IV) dioxide, which is often released into the atmosphere without use. In addition to sulfide ores, a lot of sulfur is found in the form of sulfates, for example, calcium sulfate (gypsum), barium sulfate (barite). Sea water and many mineral waters contain water-soluble magnesium and sodium sulfates. Hydrogen sulfide (hydrogen sulfide) is found in some mineral waters. In industry, sulfur can be obtained as a by-product of processes in smelters, coke ovens, oil refining, from flue or natural gases. Sulfur is extracted from natural underground deposits by melting it with superheated water and delivering it to the surface with compressed air and pumps. In the frash process for the extraction of sulfur from sulfur-bearing deposits in a concentric tube installation patented by G. Frasch in 1891, sulfur is obtained with a purity of up to 99.5%.

Properties.

Sulfur has the form of a yellow powder or brittle crystalline mass, odorless and tasteless and insoluble in water. Sulfur has several allotropic modifications. The most famous are the following: crystalline sulfur - rhombic (native sulfur, a-S) and monoclinic (prismatic sulfur, b-S); amorphous - colloidal (sulfuric milk) and plastic; intermediate amorphous-crystalline - sublimated (sulfur color).

Crystalline sulfur.

Crystalline sulfur has two modifications; one of them, rhombic, is obtained from a solution of sulfur in carbon disulfide (CS 2) by evaporation of the solvent at room temperature. In this case, diamond-shaped translucent crystals of light yellow color are formed, easily soluble in CS 2 . This modification is stable up to 96°C; at higher temperatures, the monoclinic form is stable. During natural cooling of molten sulfur in cylindrical crucibles, large crystals of rhombic modification with a distorted shape grow (octahedrons, in which corners or faces are partially “cut off”). Such material is called lump sulfur in the industry. Monoclinic modification of sulfur is a long transparent dark yellow needle-shaped crystals, also soluble in CS 2 . When monoclinic sulfur is cooled below 96 ° C, a more stable yellow rhombic sulfur is formed.

non-crystalline sulfur.

In addition to these crystalline and amorphous forms, there is an intermediate form known as sulfur color or sublimated sulfur, which is obtained by condensing sulfur vapor without passing through the liquid phase. It consists of tiny grains with a crystallization center and an amorphous surface. This form slowly and incompletely dissolves in CS 2 . After treatment with ammonia to remove impurities such as arsenic, a product known medically as washed sulfur is obtained, which is used in a similar way to colloidal sulfur.

liquid state.

Sulfur molecules consist of a closed chain of eight atoms (S 8). Liquid sulfur has an unusual property: as the temperature rises, its viscosity increases. Below 160 ° C, sulfur is a typical yellowish liquid, its composition corresponds to the formula S 8 and is designated l-S. As the temperature rises, the S 8 ring molecules begin to break and join with each other, forming long chains ( m-S), the color of liquid sulfur becomes dark red, the viscosity increases, reaching a maximum at 200–250 ° C. With a further increase in temperature, liquid sulfur brightens, long chains break, forming short ones, with less ability to intertwine, which leads to lower viscosity.

Gas.

Sulfur boils at 444.6 ° C, forming orange-yellow vapors, consisting mainly of S 8 molecules. With an increase in temperature, the color of the vapors turns dark red, then pale, and at 650 ° C, straw yellow. Upon further heating, the S 8 molecules dissociate, forming the equilibrium forms S 6 , S 4 and S 2 at different temperatures. And, finally, at >1000°C the vapors consist practically of S 2 molecules, and at 2000°C they consist of monatomic molecules.

Chemical properties.

Sulfur is a typical nonmetal. It has six electrons in its outer electron shell, and it more easily accepts electrons from other elements than gives up its own. It reacts with many metals with the release of heat (for example, when combined with copper, iron, zinc). It combines with almost all non-metals, although not so vigorously.

Connections.

sulphur dioxide

It is formed during the combustion of sulfur in air, in particular, during the roasting of sulfide ores of metals. Sulfur dioxide is a colorless gas with a suffocating odor. It is sulfurous acid anhydride, it readily dissolves in water to form sulfurous acid. The dioxide is easily liquefied (bp –10°C) and stored in steel cylinders. Dioxide is used in the production of sulfuric acid, in refrigeration, for bleaching textiles, wood pulp, straw, beet sugar, for preserving fruits and vegetables, for disinfection, in brewing and food industries.

sulfurous acid

H 2 SO 3 exists only in dilute solutions (less than 6%). It is a weak acid that forms medium and acidic salts (sulfites and hydrosulfites). Sulfurous acid is a good reducing agent, reacting with oxygen to form sulfuric acid. Sulfurous acid has several uses, including the bleaching of silk, wool, paper, wood pulp and similar substances. It is used as an antiseptic and preservative, especially to prevent wine from fermenting in barrels, to prevent grain from fermenting while extracting starch. Acid is also used to preserve food. The most important of its salts is calcium hydrosulfite Ca(HSO 3) 2 used in the processing of wood chips into cellulose.

Sulfur trioxide

SO 3 (sulfuric anhydride), which forms sulfuric acid with water, is either a colorless liquid or a white crystalline substance (crystallizes at 16.8 ° C; bp 44.7 ° C). It is formed during the oxidation of sulfur dioxide with oxygen in the presence of an appropriate catalyst (platinum, vanadium pentoxide). Sulfur trioxide smokes strongly in moist air and dissolves in water, forming sulfuric acid and generating a lot of heat. It is used in the production of sulfuric acid and the production of synthetic organic substances.

Sulphuric acid

H2SO4. Anhydrous H 2 SO 4 is a colorless oily liquid that dissolves SO 3 to form oleum. Miscible with water in any ratio. When dissolved in water, hydrates are formed with the release of a very large amount of heat; therefore, in order to avoid splashing of acid, it is usually when dissolving carefully, gradually add acid to water, and not vice versa. Concentrated acid absorbs water vapor well and is therefore used to dry gases. For the same reason, it leads to carbonization of organic substances, especially carbohydrates (starch, sugar, etc.). In case of contact with the skin, it causes severe burns, the vapors corrode the mucous membranes of the respiratory tract and eyes. Sulfuric acid is a strong oxidizing agent. Conc. H 2 SO 4 oxidizes HI, HBr to I 2 and Br 2, respectively, coal to CO 2, sulfur to SO 2, metals to sulfates. A dilute acid also oxidizes metals in the voltage series to hydrogen. H 2 SO 4 is a strong dibasic acid that forms medium and acidic salts - sulfates and hydrosulfates; most of its salts are soluble in water, with the exception of barium, strontium and lead sulfates, calcium sulfate is sparingly soluble.

Sulfuric acid is one of the most important products of the chemical industry (producing alkali, acids, salts, mineral fertilizers, chlorine). It is obtained mainly by contact or tower method according to the concept:

Most of the acid produced is used for the production of mineral fertilizers (superphosphate, ammonium sulfate). Sulfuric acid serves as a feedstock for the production of salts and other acids, for the synthesis of organic substances, artificial fibers, for the purification of kerosene, petroleum oils, benzene, toluene, in the manufacture of paints, etching of ferrous metals, in the hydrometallurgy of uranium and some non-ferrous metals, for the production of detergents. and medicines, as an electrolyte in lead batteries and as a desiccant.

Thiosulfuric acid

H 2 S 2 O 3 is structurally similar to sulfuric acid except for the replacement of one oxygen with a sulfur atom. The most important derivative of the acid is sodium thiosulfate Na 2 S 2 O 3 - colorless crystals formed by boiling sodium sulfite Na 2 SO 3 with a sulfur color. Sodium thiosulfate (or hyposulfite) is used in photography as a fixer (fixer).

Sulfonal

(CH 3) 2 C (SO 2 C 2 H 5) 2 - a white crystalline substance, odorless, slightly soluble in water, is a drug and is used as a sedative and hypnotic.

hydrogen sulfide

H 2 S (hydrogen sulfide) is a colorless gas with a sharp unpleasant smell of rotten eggs. It is somewhat heavier than air (density 1.189 g / dm 3), easily liquefies into a colorless liquid and is highly soluble in water. The solution in water is a weak acid with pH ~ 4. Liquid hydrogen sulfide is used as a solvent. Solution and gas are widely used in qualitative analysis for the separation and determination of many metals. Inhalation of a small amount of hydrogen sulfide causes headache and nausea, large amounts or continuous inhalation of hydrogen sulfide cause paralysis of the nervous system, heart and lungs. Paralysis occurs unexpectedly, as a result of a violation of the vital functions of the body.

Sulfur monochloride

S 2 Cl 2 is a fuming amber-colored oily liquid with a pungent odor, tearing and making breathing difficult. It smokes in humid air and decomposes in water, but is soluble in carbon disulfide. Sulfur monochloride is a good solvent for sulfur, iodine, metal halides and organic compounds. The monochloride is used in rubber vulcanization, printing ink and insecticides. Reaction with ethylene produces a volatile liquid known as mustard gas (ClC 2 H 4) 2 S, a toxic compound used as an irritant chemical warfare agent.

carbon disulfide

CS 2 (carbon disulfide) is a pale yellow liquid, poisonous and flammable. CS 2 is synthesized from the elements in an electric furnace. The substance is insoluble in water, has a high refractive index, high vapor pressure, low boiling point (46° C). Carbon disulfide - an effective solvent for fats, oils, rubber and rubber - is widely used for the extraction of oils, in the production of rayon, varnishes, rubber adhesives and matches, the destruction of barn weevils and clothing moths, and for soil disinfection.