Binary compounds are substances that are formed by two different chemical elements. This term is used to denote the qualitative and quantitative composition of inorganic compounds.
Binary chemical compounds are considered an important object in the study of the nature of substances. When describing them, the following concepts are used: bond polarization, oxidation state, valency. These chemical terms make it possible to understand the essence of the formation of a chemical bond, the structural features of inorganic substances.
Let's consider the main classes of binary compounds, the features of their chemical structure and properties, some areas of their industrial application.
Oxides
This class of inorganic substances is the most common in nature. Among the well-known representatives of this group of compounds, we single out:
- silicon oxide (river sand);
- hydrogen oxide (water);
- carbon dioxide;
- clay (aluminum oxide);
- iron ore (iron oxides).
Such binary compounds are complex substances, which necessarily contain oxygen, exhibiting an oxidation state of -2.
Aggregatestate of oxides
Compounds of copper, calcium, iron are crystalline solids. The same state of aggregation have oxides of some non-metals, such as hexavalent sulfur, pentavalent phosphorus, silicon. The liquid under normal conditions is water. The vast majority of oxygen compounds of non-metals are gases.
Features of education
Many binary oxygen compounds are formed in nature. For example, during the combustion of fuel, respiration, decay of organic matter, carbon dioxide (carbon monoxide 4) is formed. In air, its volume content is about 0.03 percent.
Similar binary compounds are the products of volcano activity, as well as an integral part of mineral water. Carbon dioxide does not support combustion, so this chemical compound is used to extinguish fires.
Volatile hydrogen compounds
Such binary compounds are an important group of substances containing hydrogen. Among the representatives of industrial importance, we note methane, water, hydrogen sulfide, ammonia, as well as hydrogen halides.
Part of volatile hydrogen compounds is present in soil water, living organisms, so we can talk about their geochemical and biochemical role.
To make binary compounds of this type, hydrogen, which has a valence, is put in the first place. The second element is a non-metal with a negative oxidation state.
For indexingin a binary compound between valences, the least common multiple is determined. The number of atoms of each element is determined by dividing it by the valency of each element that makes up the compound.
Hydrochloride
Consider the formulas of binary compounds: hydrogen chloride and ammonia. It is these substances that are important for the modern chemical industry. HCl under normal conditions is a gaseous compound, highly soluble in water. Dissolving hydrogen chloride gas produces hydrochloric acid, which is used in many chemical processes and production chains.
This binary compound is found in the gastric juice of humans and animals, it is a barrier to pathogenic microbes that enter the stomach with food.
Among the main areas of application of hydrochloric acid, we highlight the production of chlorides, the synthesis of chlorine-containing products, the pickling of metals, the cleaning of pipes from oxides and carbonates, leather production.
Ammonia, having the formula NH3, is a colorless gas with a specific pungent odor. Its unlimited solubility in water makes it possible to obtain ammonia, which is in demand in medicine. In nature, this binary compound is formed during the decay of organic products, which contain nitrogen.
Classification of oxides
An oxygen-containing binary compound of a metal having a valence of 1 or 2 is the mainoxide. For example, this group includes oxides of alkali and alkaline earth metals.
Oxides of non-metals, as well as metals with a valence greater than 4, are acidic compounds.
Depending on the chemical properties of the representatives of this class are divided into s alt-forming and non-s alt-forming groups.
Among the typical representatives of the second group, we note carbon monoxide (CO), nitric oxide 1 (NO).
Formation of systematic names of compounds
Among the tasks offered to graduates taking the state exam in chemistry, there is this: "Make the molecular formulas of possible binary oxygen compounds of sulfur (nitrogen, phosphorus)". In order to cope with the task, it is necessary to have an idea not only about the algorithm, but also about the features of the nomenclature of this class of inorganic substances.
When forming the name of a binary compound, initially indicate the element that is located on the right in the formula, adding the suffix "id". Next, indicate the name of the first element. For covalent compounds, prefixes are added, by which it is possible to establish a quantitative ratio between the constituent parts of a binary compound.
For example, SO3 is sulfur trioxide, N2O4 is dinitrogen tetroxide, I2CL6 – diode hexachloride.
If a binary compound contains a chemical element capable of exhibiting different oxidation states, the oxidation state is indicated in parentheses after the name of the compound.
For example, two iron compoundsdiffer in name: FeCL3 - iron oxide (3), FeCL2 - iron oxide (2).
For hydrides, in particular non-metallic elements, use trivial names. So, H2O is water, HCL is hydrogen chloride, HI is hydrogen iodide, HF is hydrofluoric acid.
Cations
Positive ions of those elements that are capable of forming only one stable ion are given the same names as the symbols themselves. These include all representatives of the first and second groups of the periodic system of Mendeleev.
For example, sodium and magnesium cations look like: Na+, Mg2+. Transition elements are capable of forming several types of cations, so the name must indicate the valency that appears in each individual case.
Anions
Simple (monatomic) and complex (polyatomic) anions use the suffix -id.
The suffix -am is a common oxoanion of a certain element. For the oxoanion of an element that is in the formula with a lower oxidation state, the suffix -it is used. The prefix hypo- is used for the minimum oxidation state, and per- is used for the maximum value. For example, the ion O2- is an oxide ion, and O- is a peroxide.
There are various trivial names for hydrides. For example, N2H4 is called hydrazine, and PH3 is called phosphine.
Sulfur-containing oxoanions have the following names:
- SO42- - sulfate;
- S2O32- - thiosulfate;
- NCS- - thiocyanate.
S alts
Many final tests in chemistry offer the following task: "Make formulas for binary compounds of metals." If such compounds contain anions of chlorine, bromine, iodine, such compounds are called halides and belong to the class of s alts. When formulating these binary compounds, the metal is placed first, followed by the corresponding halide ion.
To determine the number of atoms of each element, find the smallest multiple between the valences, when dividing, get indices.
Such compounds have high melting and boiling points, good solubility in water, under normal conditions they are solids. For example, sodium and potassium chlorides are part of sea water.
Table s alt has been used by people since ancient times. Currently, the use of this binary compound is not limited to eating. Electrolysis of an aqueous solution of sodium chloride produces sodium metal and chlorine gas. These products are used in various manufacturing processes such as sodium hydroxide, hydrogen chloride.
Meaning of binary compounds
This group includes a huge number of substances, so we can say with confidence about the scale of their use in various fields of human activity. Ammonia is used in the chemical industry as aprecursor in the manufacture of nitric acid, the production of mineral fertilizers. It is this binary compound that is used in fine organic synthesis and has been used in refrigeration for a long time.
Due to the unique hardness of tungsten carbide, this compound has found application in the manufacture of a variety of cutting tools. The chemical inertness of this binary compound allows it to be used in aggressive environments: laboratory equipment, ovens.
"Laughing gas" (nitric oxide 1) mixed with oxygen is used in medicine for general anesthesia.
All binary compounds have a covalent or ionic nature of the chemical bond, a molecular, ionic or atomic crystal lattice.
Conclusion
When drawing up formulas for binary compounds, it is necessary to follow a certain algorithm of actions. The element that exhibits a positive oxidation state (has a lower electrical negativity value) is written first. When determining the value of the oxidation state of the second element, the number of the group in which it is located is subtracted from eight. If the numbers obtained differ from each other, the least common multiple is determined, then the indices are calculated.
In addition to oxides, these compounds include carbides, silicides, peroxides, hydrides. Aluminum and calcium carbides are used for laboratory production of methane and acetylene, peroxides are used in the chemical industry as strong oxidizers.
A halide like hydrogen fluoride(hydrofluoric acid), used in electrical engineering for soldering. Among the most important binary compounds, without which it is difficult to imagine the existence of living organisms, water is in the lead. The structural features of this inorganic compound are studied in detail in the school chemistry course. It is on her example that the guys get an idea of the sequence of actions when compiling formulas for binary compounds.
In conclusion, we note that it is difficult to find such a sphere of modern industry, an area of human life, wherever various binary compounds are used.
