Inorganic chemistry is part of general chemistry. It deals with the study of 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 study of organic chemistry).
Description
Chemistry is a complex science. Its division into categories is purely arbitrary. For example, inorganic and organic chemistry are linked by compounds called bioinorganic. These include hemoglobin, chlorophyll, vitamin B12 and many enzymes.
Very often, when studying substances or processes, one has 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 involves a wide range of physical chemistry methods, since they can combine properties characteristic of a science such asphysics. The quality of substances is affected by conductivity, magnetic and optical activity, the effect of catalysts and other "physical" factors.
Generally, inorganic compounds are classified according to their function:
- acids;
- grounds;
- oxides;
- s alt.
Oxides are often divided into metals (basic oxides or basic anhydrides) and non-metal oxides (acidic oxides or acid anhydrides).
Origination
The history of inorganic chemistry is divided into several periods. At the initial stage, knowledge was accumulated 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 doctrine of the convertibility of elements.
In the first half of the fifteenth century, epidemics raged. Especially the population suffered from smallpox and plague. Aesculapius assumed that diseases are caused by certain substances, and the fight against them 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 emergence of a new science
During the Renaissance, chemistry from a purely practical field of study began to "acquire" theoretical concepts. Scientists tried to explain the deep processes that occur with substances. In 1661, Robert Boyle introduces the concept of "chemical element". In 1675 Nicholas Lemmer separates the chemical elementsminerals from plants and animals, thereby stipulating the study of chemistry of inorganic compounds separately from organic ones.
Later, chemists tried to explain the phenomenon of combustion. The German scientist Georg Stahl created the phlogiston theory, according to which a combustible body rejects a non-gravitational phlogiston particle. In 1756, Mikhail Lomonosov experimentally proved that the combustion of certain metals is associated with particles of air (oxygen). Antoine Lavoisier also refuted the theory of phlogistons, becoming the founder of the modern theory of combustion. He also introduced the concept of "compound of chemical elements".
Development
The next period begins with the work of John D alton and attempts to explain chemical laws through the interaction of substances at the atomic (microscopic) level. The first chemical congress in Karlsruhe in 1860 defined the concepts of atom, valency, equivalent, and molecule. Thanks to the discovery of the periodic law and the creation of the periodic system, Dmitry Mendeleev proved that the atomic-molecular theory is connected not only with chemical laws, but also with the physical properties of elements.
The next stage in the development of inorganic chemistry is associated with the discovery of radioactive decay in 1876 and the elucidation of the design of the atom in 1913. A study by Albrecht Kessel and Gilbert Lewis in 1916 solves the problem of the nature of chemical bonds. Based on the theory of heterogeneous equilibrium by Willard Gibbs and Henrik Roszeb, in 1913 Nikolai Kurnakov created one of the main methods of modern inorganic chemistry -physical and chemical analysis.
Fundamentals of inorganic chemistry
Inorganic compounds occur naturally in the form of minerals. The soil may contain iron sulfide such as pyrite or calcium sulfate in the form of gypsum. Inorganic compounds also occur 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.
S alts
Many inorganic compounds are ionic compounds composed of cations and anions. These are the so-called s alts, which are the object of research in inorganic chemistry. Examples of ionic compounds are:
- Magnesium chloride (MgCl2), which contains Mg2+ cations and Cl- anions .
- Sodium oxide (Na2O), which consists of cations Na+ and anions O2- .
In each s alt, the proportions of ions are such that the electric charges are in equilibrium, that is, the compound as a whole is electrically neutral. Ions are described by their oxidation state and the ease of formation that follows from the ionization potential (cations) or electron affinity (anions) of the elements from which they are formed.
Inorganic s alts include oxides, carbonates, sulfates and halides. Many compounds are characterized by high melting points. Inorganic s alts are usually solid crystalline formations. Another important feature is theirsolubility in water and ease of crystallization. Some s alts (eg NaCl) are very soluble in water, while others (eg SiO2) are almost insoluble.
Metals and alloys
Metals such as iron, copper, bronze, brass, aluminum are a group of chemical elements at the bottom left of the periodic table. This group includes 96 elements that are characterized by high thermal and electrical conductivity. They are widely used in metallurgy. Metals can be conditionally 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 substances obtained by melting and mixing two or more metals in a liquid state. They consist of a base (dominant elements in percentage terms: iron, copper, aluminum, etc.) with small additions of alloying and modifying components.
Mankind uses about 5000 types of alloys. 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, calcium);
- 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.).
Nonmetals
Non-metals can be both 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.
The most typical non-metals are halogens. In reaction with metals, they form compounds whose bond is mainly ionic, such as KCl or CaO. When interacting with each other, non-metals can form covalently bonded compounds (Cl3N, ClF, CS2, etc.).
Bases and acids
Bases are complex substances, the most important of which are water-soluble hydroxides. When dissolved, they dissociate with metal cations and hydroxide anions, and their pH is greater than 7. Bases can be considered chemically opposite to acids because water-dissociating acids increase the concentration of hydrogen ions (H3O+) until the base is reduced.
Acids are substances that participate in chemical reactions with bases, taking electrons from them. Most acids of practical importance are water-soluble. When dissolved, they dissociate from hydrogen cations(Н+) and acidic anions, and their pH is less than 7.
