Let's talk about how to determine the nature of the oxide. To begin with, it is customary to subdivide all substances into two groups: simple and complex. Simple substances are divided into metals and non-metals. Complex compounds are divided into four classes: bases, oxides, salts, acids.
Definition
Since the nature of the oxides depends on their composition, first we give a definition of this class of inorganic substances. Oxides are complex substances that consist of two elements. Their peculiarity is that oxygen is always located in the formula as the second (last) element.
The most common option is the interaction with oxygen of simple substances (metals, non-metals). For example, the interaction of magnesium with oxygen produces magnesium oxide, which exhibits basic properties.
Nomenclature
The nature of the oxides depends on their composition. There are certain rules by which such substances are called.
If the oxide is formed by metals of the main subgroups, valency is not indicated. For example, calcium oxide CaO. If the metal of the same subgroup, which has a variable valency, is the first to be located in the compound, then it is necessarily indicated by a Roman numeral. It is placed after the name of the compound in parentheses. For example, there are iron oxides (2) and (3). When compiling the formulas of oxides, it must be remembered that the sum of the degrees of oxidation in it must be equal to zero.
Classification
Let us consider how the nature of the oxides depends on the degree of oxidation. Metals having an oxidation state of +1 and +2 form basic oxides with oxygen. A specific feature of such compounds is the basic nature of the oxides. Such compounds enter into chemical interaction with salt-forming non-metal oxides, forming salts with them. In addition, basic oxides react with acids. The product of the interaction depends on the quantity in which the starting materials were taken.
Non-metals, as well as metals with oxidation states from +4 to +7, form acid oxides with oxygen. The nature of the oxides involves interaction with bases (alkalis). The result of the interaction depends on how much of the original alkali was taken. With its lack, an acid salt is formed as a reaction product. For example, in the reaction of carbon monoxide (4) with sodium hydroxide, sodium bicarbonate (acid salt) is formed.
In the case of the interaction of acid oxide with excess alkali, the reaction product will be a middle salt (sodium carbonate). The nature of acid oxides depends on the degree of oxidation.
They are divided into salt-forming oxides (in which the oxidation state of an element is equal to the group number), as well as indifferent oxides that are not able to form salts.
Amphoteric oxides
There is also an amphoteric character of the properties of oxides. Its essence lies in the interaction of these compounds with both acids and alkalis. What oxides exhibit dual (amphoteric) properties? These include binary metal compounds with an oxidation state of +3, as well as oxides of beryllium, zinc.
Production methods
There are various methods for producing oxides. The most common option is the interaction with oxygen of simple substances (metals, non-metals). For example, the interaction of magnesium with oxygen produces magnesium oxide, which exhibits basic properties.
In addition, oxides can also be obtained by the interaction of complex substances with molecular oxygen. For example, during the combustion of pyrite (iron sulfide 2), two oxides can be obtained at once: sulfur and iron.
Another option for the production of oxides is the decomposition of salts of oxygen-containing acids. For example, the decomposition of calcium carbonate can produce carbon dioxide and calcium oxide (quicklime).
Basic and amphoteric oxides are formed during the decomposition of insoluble bases. For example, upon calcination of iron hydroxide (3), iron oxide (3) is formed, as well as water vapor.
Conclusion
Oxides are a class of inorganic substances with wide industrial application. They are used in the construction industry, pharmaceutical industry, medicine.
In addition, amphoteric oxides are often used in organic synthesis as catalysts (accelerators of chemical processes).