Of the entire periodic system, most of the elements are a group of metals. Alkaline, alkaline earth, amphoteric, transitional, radioactive - there are a lot of them. All metals play a huge role not only in nature and the biological life of man, but also in various industries. Not for nothing that the 20th century was called the "iron".
Metals: general characteristic
All metals are united by common chemical and physical properties, by which they are easily distinguished from non-metallic substances. So, for example, the structure of the crystal lattice allows them to be:
- conductors of electric current;
- good heat conductors;
- malleable and ductile;
- durable and shiny.
Of course, there are differences among them. Some metals shine with silver, others with more dull white, and others with red and yellow in general. There are also differences in terms of thermal and electrical conductivity. However, all the same, these parameters are common to all metals, while non-metals have more differences than similarities.
By chemical nature, all metals are reducing agents. Depending on the reaction conditions and specific substances, they can also act as oxidizing agents, but rarely. Able to form numerous substances. Chemical compounds of metals are found in nature in large quantities in the composition of ore or minerals, minerals and other rocks. The oxidation state of metals is always positive, it can be constant (aluminum, sodium, calcium) or variable (chromium, iron, copper, manganese).
Many of them are widely used as building materials and are used in a wide variety of branches of science and technology.
Chemical compounds of metals
Among these, there are 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, sulfides and others - binary compounds with non-metals, most often belong to the class of salts (except oxides).
- Hydroxides - the general formula Me + x (OH) x .
- Salt. Metal compounds with acid residues. May be different:
- medium;
- sour;
- double;
- basic;
- complex.
4. Metal compounds with organic substances - organometallic structures.
5. Compounds of metals with each other are alloys that are obtained in different ways.
Metal compounding options
Substances in which two different metals or more can simultaneously be located are divided into:
- alloys;
- double salts;
- complex compounds;
- intermetallic compounds.
Methods of joining metals with each other also vary. For example, to obtain alloys using the method of melting, mixing and solidification of the resulting product.
Intermetallics are formed as a result of direct chemical reactions between metals, often occurring with an explosion (for example, zinc and nickel). Such processes require special conditions: the temperature is very high, pressure, vacuum, lack of oxygen, and others.
Double salts and complex compounds can form when the solutions of the starting materials are merged, as well as when they are fused.
The manufacture of metal products also implies their connection with each other. To do this, use methods such as:
- welding (gas, electric and so on);
- soldering with different types of solders;
- thread;
- riveting.
The main condition is to create a product that can be resistant to corrosion and in which there will be no seams and impurities, cracks.
Alkali metal compounds and their use
Alkaline elements are those located in the first group of the main subgroup of the periodic system. There are only 6 of them, and they were open almost all at the same time with a short time interval. In the form of simple substances in nature, these elements do not occur.
Due to the high chemical activity, working with them is very difficult and dangerous. Therefore, I had to work hard to isolate them in their pure form. Much earlier, people began to use various compounds of alkali metals. Some of them have been known since antiquity and have not lost their importance and relevance today. They are used in engineering, construction, medicine, food industry, chemical industry, metallurgy, mechanical engineering, agriculture and many other sectors of the national economy. The main ones will be considered in more detail.
Types of compounds of alkali metals with other metals belong to the groups:
- intermetallic compounds;
- complex compounds;
- double salts.
Oxides
Of all alkali metals, when burned in oxygen, normal oxide is capable of producing only lithium. The rest are overly active, so they form Me 2 O 2 peroxides. From peroxides by the action of a simple metal, it is possible to obtain oxide of the normal form Me 2 O. Oxygen compounds of alkali metals have different colors.
- Lithium, potassium and sodium oxide are white crystalline powders.
- Rubidium is a yellow oxide.
- Cesium is orange.
The main field of application is the chemical industry. Alkali metal oxides react with water, forming important compounds - alkalis. This property determines the name of this group of elements. Alkali metal compounds - oxides - are only part of the total mass of significant and important substances that contain these elements.
Hydroxides (alkalis)
Hydroxy-alkali metal compounds are called alkalis, or hydroxides. All of them are very corrosive substances that can easily destroy almost any material. This is especially true for animal tissues. Therefore, it is necessary to work with alkalis with extreme caution; a deep chemical burn may occur at the site of skin contact.
The most famous substance among alkalis is caustic soda, or sodium hydroxide. This compound has been known since ancient times, where it was extracted from plant ash and used for soap making and washing. The chemical formula is NaOH. Today, caustic soda is produced in huge quantities in each country, since practically no industry is dispensed with without its participation. It is used:
- in the oil refining industry;
- in cosmetic and perfumery;
- in chemical synthesis;
- for the production of cleaning and detergents, abrasive materials;
- in the leather and textile industries and other areas.
Other metals from the alkaline group form less important and common alkalis. More or less significant is only potassium hydroxide - KOH, which is known as potassium hydroxide.
Salt
Such compounds of alkali metals, such as salts, are not only practically in demand substances, but are also present in the body of living creatures, maintaining their normal viability.
The most important salt is, of course, sodium chloride. This is ordinary table salt, which is in every home and which does not attach much importance due to its high prevalence. However, if you imagine that it will suddenly disappear, few will be happy with the consequences. It is difficult to eat unsalted food, and besides, it causes irreparable harm to health, since sodium ions necessary for the work of the heart and blood vessels do not enter the body.
Also important alkali metal compounds are carbonates. Especially sodium carbonate and bicarbonate, which in common people is called soda. It is used in the manufacture of glass, for the manufacture of detergents. You can safely clean the dishes with soda. It has good disinfecting, disinfecting, cleansing and whitening properties. It is widely used in the food industry, especially in the confectionery business and bakery. With its help, soap is brewed, washing powders are created.
Soda, salt, caustic - all these are compounds of alkali metals in nature. They exist in their pure form, forming deposits, or are part of the products of combustion of certain substances. Sometimes they are obtained in a laboratory way. But always these substances are important and valuable, as they surround a person and form his life.
Alkali metal compounds and their use are not limited only to sodium. Also common and popular in industries are 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 application
This category includes elements of the second group of the main subgroup of the system of chemical elements. Their constant oxidation state is +2. These are active reducing agents that easily enter into chemical reactions with most compounds and simple substances. They exhibit all the typical properties of metals: gloss, ductility, heat and electrical conductivity.
The most important and common of these are magnesium and calcium. Beryllium is amphoteric, barium and radium are rare elements. All of them are capable of forming the following types of compounds:
- intermetallic;
- oxides;
- hydrides;
- binary salts (compounds with non-metals);
- hydroxides;
- salts (double, complex, acidic, basic, medium).
Consider the most important compounds from a practical point of view and their scope.
Magnesium and Calcium Salts
Alkaline earth metal compounds such as salts are important for living organisms. After all, it is calcium salts that are the source of this element in the body. And without it, the normal formation of the skeleton, teeth, horns in animals, hooves, hair and coat and so on is impossible.
So, the most common salt of an alkaline earth metal of calcium is carbonate. Its other names:
- a piece of chalk;
- marble;
- limestone;
- dolomite.
It is used not only as a supplier of calcium ions to a living organism, but also as building material, raw materials for chemical industries, in the cosmetics industry, glass and so on.
Alkaline earth metal compounds such as sulfates are also important. For example, barium sulfate (the medical name is "barite porridge") is used in X-ray diagnostics. Calcium sulfate in the form of crystalline hydrate is gypsum found in nature. It is used in medicine, construction, stamping molds.
Alkaline earth metal phosphors
These substances have been known since the Middle Ages. They used to be called phosphors. This name is found now. By their nature, these compounds are sulfides of magnesium, strontium, barium, calcium.
With a certain treatment, they are able to exhibit phosphorescent properties, and the glow is very beautiful, from red to bright purple. This is used in the manufacture of road signs, workwear and other things.
Complex compounds
Substances that include two or more different elements of a metallic nature are complex compounds of metals. Most often they are liquids that have beautiful and colorful colors. They are used in analytical chemistry for the qualitative determination of ions.
Such substances are able to form not only alkaline and alkaline earth metals, but all the rest. There are hydroxocomplexes, aquacomplexes and others.