Of all of the periodic system of elements is a large part of the group of metals.Alkali, alkaline earth, amphoteric, transient, radioactive - a lot of them.All metals play an important role not only in nature and biological life, but also in various industries.Not for nothing that the XX century has been called the "iron".
Metals: general characteristics
All metals are united by common chemical and physical properties, which are easy to distinguish from non-metallic materials.For example, the structure of the crystal lattice allows them to be:
- conductors of electric current;
- good heat conductors;
- malleable and ductile;
- strong and shiny.
Of course, there are also differences.Some metals shine silver, the other - a matte white, and others - all red and yellow.Also, there are differences in terms of thermal and electrical conductivity.However, all these parameters are equal - common to all metals, whereas the non-metals are more differences than similarities.
Chemically, all metals - reducing.Depending on the reaction conditions and the specific substance can also act as oxidizing agents, however rare.Numerous substances capable of forming.The chemical compounds of metals occur naturally in a large quantity in the composition of the ore or minerals, minerals and other species.The oxidation state of metal is always positive, it may be permanent (aluminum, sodium, calcium) or variable (chromium, iron, copper, manganese).
Many of them are widely used as building materials, are used in various branches of science and technology.
metal compound
Among these may be mentioned several main classes of substances that are products of the interaction of metals with other elements and substances.
- oxides, hydrides, nitrides, silicides, phosphides, ozonides, carbides, sulphides and others - binary compounds with non-metals, mostly belong to the class of salts (except the oxides).
- hydroxides - the general formula Me + x (OH) x.
- salts.Metal compounds with acid residues.Can be different:
- average;
- acid;
- double;
- basic;
- complex.
4. The metal compounds with organic compounds - organometallic structure.
5. The metal compounds with each other - alloys, which can be obtained in different ways.
options metal compounds
Substances which can simultaneously be two different metal and more, divided into:
- alloys;
- double salts;
- complex compounds;
- intermetallic compounds.
metal joining methods also vary among themselves.For example, to use the method of melting the alloy, mixing and curing the resultant product.
intermetallics formed due to direct chemical reactions between metals, often occurring with explosion (such as zinc and nickel).For these processes need special conditions: the temperature is very high, pressure, vacuum, lack of oxygen and others.
double salts and complex compounds can be formed when draining the raw material solution, as well as their fusion.
Manufacturing of metal also means connecting them together.For this purpose, methods such as:
- welding (gas, electric, and so on);
- brazing different types of solders;
- thread;
- riveting.
main condition - is to create a product that could be resistant to corrosion and in which there will be seams and impurities slots.
alkali metal compounds and their use
called Alkaline elements located in the first group of the main subgroup of the periodic system.There are only six, and they were discovered almost all simultaneously with a small time interval.In the form of simple substances in the nature of these elements does not occur.
Due to the high chemical activity of working with them is very difficult and dangerous.So we had to work hard to isolate them in pure form.Long before people began to use various alkali metal compounds.Some of them have been known since ancient times and have not lost importance and relevance today.They are used in engineering, construction, medicine, food industry, chemical industry, metallurgy, agriculture and many other parts of the economy.The main ones are closer look.
Types alkali metal compounds with other metals are among the groups:
- intermetallic compounds;
- complex compounds;
- double salts.
oxides
Of the alkali metals when burned in oxygen Normal oxide capable of producing only lithium.The rest of the exhibit excessive activity, so Me2O2 form peroxides.Because of the influence of peroxides simple metal oxide can be obtained Me2O normal form.Oxygen compounds of alkali metals have different colors.
- oxide of lithium, potassium and sodium - white crystalline powder.
- Rubidium - yellow coloring oxide.
- Cesium - orange.
main applications - chemical industry.Alkali metal oxides react with water to form important compound - alkali.This property is due and the name of this group of elements.Compounds of alkali - metal oxides - only part of the total mass of significant and important substances composed of these elements.
hydroxides (lye)
alkali metal compound with gidroksogrupp called alkali or hydroxides.All of them - a very caustic substance that can easily destroy almost any material.This is especially true of animal tissues.Therefore, working with alkalis should be very cautious, to the point of contact with the skin can cause deep chemical burns.
most famous among alkaline substance is caustic soda, or sodium hydroxide.This compound is known from ancient times where it was extracted from the ashes of plants and used for soap making and washing clothes.Chemical formula - NaOH.Today, caustic soda produces an enormous amount in each country, as without him can not do almost no one branch of production.It is used:
- in the refining industry;
- in the cosmetics and perfume;
- in chemical synthesis;
- for the production of detergents and cleaning agents, abrasives;
- in the leather and textile industries and other fields.
Other metals from the group of alkaline form is not as important and common bases.More or less significant is a potassium hydroxide - KOH, which is known as caustic potash.
salts
Such compounds, alkali metal salts, are not only virtually claimed substances, but also present in the body of living creatures, maintaining their normal vitality.
most important salt is, of course, sodium chloride.This is a common table salt, which is present in every home, and which do not attach special significance due to the high prevalence.However, if we imagine that she suddenly disappears, few people would be delighted consequences.Unsalted food is a complex, besides, it does irreparable harm, since the body does not act sodium ions needed for the heart and blood vessels.
also important alkali metal compounds - is carbonate.Especially carbonate and sodium bicarbonate, which is called in common soda.Its use in the production of glass, for manufacturing detergents.Soda can safely clean the dishes.It has good disinfectant, disinfectant, cleansing and bleaching properties.Widely used in the food industry, particularly in the confectionery business and bakery.With the help of boiled soap, washing powders create.
soda, salt, caustic soda - all these alkali metal compounds in nature.They exist in a pure form, forming deposits or part of the combustion products of various substances.Sometimes they are prepared by the laboratory method.But these substances are always important and valuable as surround man and form his life.
alkali metal compounds and their use are not limited to sodium.It is also common and popular sectors of the economy salts such as:
- potassium chloride;
- potassium nitrate (potassium nitrate);
- potassium carbonate;
- sulfate.
All of them are valuable mineral fertilizers used in agriculture.
Alkaline earth metals - compounds and their use
This category includes the elements of the second group of the main group of chemical elements.Their constant oxidation state of +2.This active reducing agents, easily reacts with the majority of compounds and simple substances.Exhibit all the typical properties of metals shine, ductility, thermal and electrical conductivity.
most important and common ones are magnesium and calcium.Beryllium exhibits amphoteric, barium and radium are rare elements.All of them are able to form the following types of connections:
- intermetallic;
- oxides;
- hydrides;
- binary salt (compounds with non-metals);
- hydroxides;
- salt (double, complex, acidic, basic, intermediate).
consider the most important compound from a practical point of view and their applications.
magnesium and calcium salts
Such compounds, alkaline earth metal salts are important for living organisms.After all, it is a source of calcium salts of this element in the body.And without it is impossible the normal formation of the skeleton, teeth, horns, animal, hooves, hair and coat, and so on.
Thus, the most common alkaline earth metal salt is calcium carbonate.His other name:
- chalk;
- marble;
- limestone;
- dolomite.
used not only as a supplier of calcium ions in living organisms, but also as a building material, raw materials for chemical industry, the cosmetics industry, glass and so on.
alkaline earth metal compounds such as sulfates, are also important.For example, barium sulfate (medical name "barite porridge") is used in radiology.Calcium sulphate in the form of crystalline - a gypsum which contains in nature.It is used in medicine, construction, stamping molds.
phosphorus from alkaline earth metals
These substances are known since the Middle Ages.Previously they were called phosphors.This name is found now.By their nature, these compounds - is sulfides magnesium, strontium, barium, calcium.
At a certain treatment, they are able to show phosphorescent properties, the glow is very beautiful, bright red to purple.It is used in the manufacture of road signs, uniforms and other things.Complex compounds
Substances which include two or more different metallic elements of nature, - metal complex compounds.Most often, they are liquid, and has a beautiful multi-colored stains.They are used in analytical chemistry for the qualitative detection of ions.
Such substances are capable of forming not only alkali and alkaline earth metals, but also all the others.There hydroxocomplexes, aqua complexes and others.
