Sulphur - a fairly common chemical element in nature (sixteenth content in the crust and the sixth - in natural waters).There are both native sulfur (free state element) and its compounds.
Sulfur in nature
Among the most important natural sulfur minerals can be called iron pyrite, sphalerite, galena, cinnabar, stibnite.The oceans contained mainly in the form of sulfates of calcium, magnesium and sodium causing rigidity of natural waters.
How to get sulfur?
sulfur ore mining is carried out by different methods.The main way to get it is the smelting of sulfur directly in the places of occurrence.
opencast mining involves the use of excavators, removing waste rock layers that cover sulfuric ore.After crushing the ore seams blasts sent to their seroplavilny plant.
In industry sulfur produced as a by-product of processes in furnaces for melting, refining at.In large amounts, it is present in natural gas (in the form of sulfur dioxide or hydrogen sulfide), the extraction of which is deposited on the walls of the equipment used.Trapped gas from sulfur is used in fine chemical industry as raw materials for production of various products.
This compound can be prepared from natural and sulfur dioxide.For this method the Claus used.It is the use of "sulfur pits" in which there is a sulfur degassing.The result is a modified sulfur, is widely used in the production of asphalt.
main allotropic modifications of sulfur
Sulphur inherent allotropy.A large number of allotropic modifications.The most famous are rhombic (crystalline), monoclinic (needle) and plastic sulfur.The first two versions are stable, and the third during solidification turns into a rhombus.
physical properties characterizing sulfur
molecules orthorhombic (α-S) and monoclinic (β-S) contain modifications to 8 sulfur atoms, which are connected in a closed loop single covalent bonds.
Under normal conditions, sulfur is rhombic modification.It is a yellow crystalline solid with a density of 2.07 g / cm3.It melts at 113 ° C.The density of monoclinic sulfur is 1.96 g / cm3, its melting temperature is 119.3 ° C.Upon melting
sulfur increases in volume and becomes yellow liquid which turns brown at 160 ° C and becomes a viscous dark brown mass upon reaching about 190 ° C.At temperatures above this value, the viscosity of sulfur decreases.At about 300 ° C, it again becomes liquid flow condition.This is because during heating the sulfur polymerizes, increasing temperature increases chain length.And when the temperature values over 190 ° C there is the destruction of polymer units.
On cooling the molten sulfur naturally cylindrical crucibles in a so-called lump sulfur - rhombic crystals of large dimensions, which have distorted octahedra form a partially "cut" edges or corners.
If the molten material subjected to sudden cooling (for example, using cold water), you can get plastic sulfur is an elastic rubbery mass of brown or dark red in color with a density of 2.046 g / cm3.This modification, unlike the orthorhombic and monoclinic is unstable.Gradually (over several hours), it changes color to yellow, becomes brittle and turns into a rhombic.
Freezing sulfur vapor (very hot) liquid nitrogen formed her purple modification, which is stable at temperatures below minus 80 ° C.
in the aquatic environment is practically insoluble sulfur.However it characterized by good solubility in organic solvents.Poor conductor of electricity and heat.
boiling point of sulfur equal to 444,6 ° C.Boiling process accompanied by the release of yellow-orange fumes consisting primarily of S8 molecules, which upon subsequent heating dissociate, resulting in formation of equilibrium forms S6, S4 and S2.Further, when heated decomposes large molecules, and at a temperature above 900 degrees pairs consist almost exclusively of molecules S2, dissociate into atoms at 1500 ° C.
What are the chemical properties of sulfur has?
Sulfur is a typical non-metal.Chemical activity.Oxidation - sulfur reduction properties appear in relation to the plurality of elements.When heated, easily connected with almost all the elements, which explains its mandatory presence of metallic ores.The exception is Pt, Au, I2, N2 and inert gases.The degree of oxidation, which manifests in the compounds of sulfur, 2, 4, 6.
Properties sulfur and oxygen cause the combustion to air.The result of this interaction is the formation of sulfur dioxide (SO2) and sulfur (SO3) anhydrides used to produce sulfurous and sulfuric acids.
At room temperature, the sulfur reduction properties are manifested only in respect of the fluorine in the reaction which forms sulfur hexafluoride:
- S + 3F2 = SF6.
Upon heating (in a melt) is reacted with chlorine, phosphorus, silicon, and carbon.The reactions with hydrogen sulfide except hydrogen forms sulfane combined H2SH general formula.
oxidative properties observed in the interaction of sulfur with metals.In some cases, one can observe a rather strong reaction.The interaction with the metal sulfides are formed (sulfur compounds) and polysulfides (mnogosernistye metals).
Prolonged heating reacts with strong acids, oxidants, oxidized at the same time.
Next, consider the basic properties of sulfur compounds.
sulfur dioxide
sulfur oxide (IV), also referred to as sulfur dioxide and sulphurous anhydride, is a gas (colorless) with a sharp suffocating odor.It tends to be liquefied under pressure at room temperature.SO2 is an acidic oxide.It is characterized by good solubility in water.This forms a weak, unstable sulfurous acid, which exists only in aqueous solution.The reaction of sulfur dioxide to form alkali sulfites.
has a rather high chemical activity.The most pronounced reduction is the chemical properties of sulfur oxide (IV).Such reactions are accompanied by an increase in the degree of oxidation of sulfur.
Oxidative chemical properties manifested sulfur oxide in the presence of strong reducing agents (e.g., carbon monoxide).
sulfur trioxide
sulfur trioxide (sulfuric anhydride) - the highest sulfur oxide (VI).Under normal conditions is a colorless volatile liquid with a suffocating odor.It tends to freeze when the temperature values below 16.9 degrees.At the same time, a mixture of different crystalline modifications of solid sulfur trioxide.The high hygroscopic properties of sulfur dioxide cause its "dymlenie" in humid air.This produces droplets of sulfuric acid.Hydrogen sulfide
Hydrogen sulfide is a binary chemical compound of hydrogen and sulfur.H2S - is a poisonous, colorless gas, the characteristic features of which are the sweet taste and the smell of rotten eggs.It melts at a temperature of minus 86 ° C and boils at -60 ° C.Thermally unstable.When the temperature values above 400 ° C the decomposition of hydrogen sulfide on the S and H2.It is characterized by good solubility in ethanol.The water dissolves poorly.As a result, dissolved in water forms a weak acid hydrogen sulfide.Hydrogen sulphide is a strong reducing agent.
Flammable.In its combustion air can observe blue flame.In high concentrations it can react with many metals.
Sulfuric Acid Sulfuric acid (H2SO4) may be of various concentrations and purity.The anhydrous state is a colorless oily liquid, odorless.
The temperature at which the melted substance is 10 ° C.Boiling point is 296 ° C.The water dissolves well.When dissolving sulfuric acid hydrates are formed, with a large amount of heat.The boiling point of aqueous solutions at a pressure of 760 mm Hg.Art.greater than 100 ° C.Boiling point rise occurs with increasing acid concentration.
acidic properties of the material appear in the interaction with the basic oxides and bases.H2SO4 is diacid thereby may form as sulfates (salts medium) and hydrosulfates (acidic salt), most of which are soluble in water.
most clearly manifest the properties of sulfuric acid in the oxidation-reduction reactions.This is due to the fact that the composition of H2SO4 at the highest degree of sulfur oxidation (6).As examples of the oxidizing properties of sulfuric acid can result in reaction with copper:
- Cu + 2H2SO4 = CuSO4 + 2H2O + SO2.
Sera: useful properties
Sulphur is a trace element necessary for living organisms.It is part of the amino acid (methionine and cysteine), enzymes, and vitamins.This element is involved in the formation of the tertiary structure of the protein.The amount of chemically bound sulfur in the proteins is by weight from 0.8 to 2.4%.The content of the element in the human body is about 2 grams per 1 kg of body weight (i.e. about 0.2% of sulfur).
Useful properties of trace elements can not be overestimated.Defending the protoplasm of the blood, sulfur is an active helper of the body to fight harmful bacteria.From it depends on the number of blood clotting, that is an element helps to maintain its adequate level.Sulfur also plays a role in maintaining normal levels of concentration of bile produced by the body.
often called the "beauty mineral" because it is absolutely necessary to preserve the health of skin, hair and nails.Sulphur inherent ability to protect the body from various types of negative environmental impact.It helps to slow down the aging process.Sulphur cleanses the body of toxins and protects from radiation, which is especially important now, given the current environmental situation.
Insufficient trace element in the body can lead to poor removal of toxins, low immunity and vitality.
Sulphur - participant of bacterial photosynthesis.It is a component of the bacteriochlorophyll, and hydrogen sulfide - a source of hydrogen.
Sera: properties and applications in the industry
most widely used sulfur for sulfuric acid production.Also, the properties of the material allow its use for the vulcanization of rubber, as a fungicide in agriculture and even drug (colloidal sulfur).Moreover, sulfur is used for the production of matches and pyrotechnic compositions, it is a part for making the compositions serobitumnyh seroasfalta.
