Inorganic chemistry is part of general chemistry.She studies the properties and behavior of inorganic compounds — their structure and ability to react with other substances. This direction explores all substances, with the exception of those that are built from carbon chains (the latter are the subject of a study of organic chemistry).
Description
Chemistry is a complex science.Its division into categories is purely conditional. For example, inorganic and organic chemistry bind compounds called bioinorganic. These include hemoglobin, chlorophyll, vitamin B12 and many enzymes.
Very often when studying substances or processesit is necessary to take into account various relationships with other sciences. General and inorganic chemistry covers simple and complex substances, the number of which approaches 400,000. The study of their properties often includes a wide range of physical chemistry methods, since they can combine properties characteristic of such a science as physics. The properties of substances are influenced by conductivity, magnetic and optical activity, the effects of catalysts and other "physical" factors.
As a rule, inorganic compounds are classified according to their function:
- acids;
- grounds;
- oxides;
- salt.
Oxides are often divided into metals (basic oxides or basic anhydrides) and non-metallic oxides (acidic oxides or acid anhydrides).
Origin
The history of inorganic chemistry is divided into severalperiods. At the initial stage, the accumulation of knowledge through random observations. Since ancient times, attempts have been made to transform base metals into precious ones. The alchemical idea was promoted by Aristotle through his theory of the convertibility of elements.
В первой половине пятнадцатого века raged epidemics. Especially the population suffered from smallpox and plague. The doctors suggested that diseases are caused by certain substances, and their control should be carried out with the help of other substances. This led to the beginning of the so-called medico-chemical period. At that time, chemistry became an independent science.
The formation of a new science
During the Renaissance chemistry from a purely practicalthe field of study has become "overgrown" with theoretical concepts. Scientists tried to explain the deep processes occurring with substances. In 1661, Robert Boyle introduced the concept of "chemical element". In 1675, Nicholas Lemmer separates the chemical elements of minerals from plants and animals, thereby determining the study of chemistry of inorganic compounds separately from organic.
Later, chemists tried to explain the phenomenon of burning.German scientist Georg Steel created the phlogiston theory, according to which a combustible body rejects a non-gravitational particle of phlogiston. In 1756, Mikhail Lomonosov experimentally proved that the burning of some metals is associated with air (oxygen) particles. Antoine Lavoisier also refuted the theory of phlogistons, becoming the ancestor of the modern theory of combustion. He also introduced the concept of "combining chemical elements."
Development
Следующий период начинается с работ Джона Далтона and attempts to explain chemical laws through the interaction of substances at the atomic (microscopic) level. The first chemical congress in Karlsruhe in 1860 gave definitions of the concepts of atom, valence, equivalent and molecule. Thanks to the discovery of the periodic law and the creation of the periodic system, Dmitri Mendeleev proved that the atomic-molecular theory is associated not only with chemical laws, but also with the physical properties of the elements.
The next stage in the development of inorganic chemistryassociated with the detection of radioactive decay in 1876 and the elucidation of the construction of the atom in 1913. The study of Albrecht Kessel and Hilbert Lewis in 1916 solves the problem of the nature of chemical bonds. Based on the theory of heterogeneous equilibrium of Willard Gibbs and Henrik Roszeb, Nikolay Kurnakov in 1913 created one of the main methods of modern inorganic chemistry - physical and chemical analysis.
Basics of inorganic chemistry
Inorganic compounds in nature are found inthe form of minerals. The soil may contain iron sulfide, such as pyrite, or calcium sulfate in the form of gypsum. Inorganic compounds are also found as biomolecules. They are synthesized for use as catalysts or reagents. The first important artificial inorganic compound is ammonium nitrate, used to fertilize the soil.
Salt
Many inorganic compounds areis an ionic compound consisting of cations and anions. These are the so-called salts, which are the object of research in inorganic chemistry. Examples of ionic compounds are:
- Magnesium Chloride (MgCl2), which consists of Mg cations2+ and Cl anions-.
- Sodium Oxide (Na2O), which consists of Na cations+ and anions o2-.
In each salt, the proportions of the ions are such thatelectric charges are equilibrium, that is, the compound as a whole is electrically neutral. Ions are described by the degree of oxidation and ease of formation, which follows from the ionization potential (cations) or electronic affinity (anions) of the elements from which they are formed.
Inorganic salts include oxides,carbonates, sulfates and halides. Many compounds are characterized by a high melting point. Inorganic salts are usually solid crystalline formations. Another important feature is their solubility in water and ease of crystallization. Some salts (for example, NaCl) are readily soluble in water, while others (for example, SiO2) are almost insoluble.
Metals and alloys
Metals such as iron, copper, bronze, brass,aluminum, are a group of chemical elements in the lower left part of the periodic table. This group includes 96 elements that are characterized by high thermal conductivity and electrical conductivity. They are widely used in metallurgy. Metals can be divided into ferrous and non-ferrous, heavy and light. By the way, the most used element is iron, it occupies 95% of world production among all types of metals.
Alloys are complex substancesobtained by melting and mixing two or more metals in a liquid state. They consist of a base (the dominant elements as a percentage: iron, copper, aluminum, etc.) with small additions of alloying and modifying components.
About 5000 types of alloys are used by mankind. They are the main materials in construction and industry. By the way, there are also alloys between metals and non-metals.
Classification
In the table of inorganic chemistry, metals are divided into several groups:
- 6 elements are in the alkaline group (lithium, potassium, rubidium, sodium, francium, cesium);
- 4 - in alkaline earth (radium, barium, strontium, potassium);
- 40 - in transition (titanium, gold, tungsten, copper, manganese, scandium, iron, etc.);
- 15 - lanthanides (lanthanum, cerium, erbium, etc.);
- 15 - actinides (uranium, actinium, thorium, fermium, etc.);
- 7 - semimetals (arsenic, boron, antimony, germanium, etc.);
- 7 - light metals (aluminum, tin, bismuth, lead, etc.).
Non-metals
Non-metals can be chemical elements,and chemical compounds. In the free state, they form simple substances with non-metallic properties. In inorganic chemistry, 22 elements are distinguished. These are hydrogen, boron, carbon, nitrogen, oxygen, fluorine, silicon, phosphorus, sulfur, chlorine, arsenic, selenium, etc.
Наиболее типичными неметаллами являются галогены.In reaction with metals, they form compounds whose bonds are mainly ionic, for example, KCl or CaO. When interacting with each other, non-metals can form covalently bonded compounds (Cl3N, ClF, CS2, etc.).
Bases and acids
The bases are complex substances, the most important ofwhich are water soluble hydroxides. When dissolved, they dissociate with metal cations and hydroxide anions, and their pH is greater than 7. The bases can be considered chemically opposed to acids, because water-dissociating acids increase the concentration of hydrogen ions (H3O +) until the base decreases.
Acids are substances that are involved inchemical reactions with bases, taking away electrons from them. Most practical acids are water soluble. When dissolved, they dissociate from hydrogen cations (H+) and acid anions, and their pH is less than 7.
