Oxides, their classification and properties are the basis of such an important science as chemistry. They begin to study in the first year of studying chemistry. In such exact sciences as mathematics, physics and chemistry, all the material is interconnected, which is why the failure to assimilate the material entails a misunderstanding of new topics. Therefore, it is very important to understand the topic of oxides and fully navigate in it. We are with you today and will try to talk about this in more detail.

What are oxides?

Oxides, their classification and properties - this is what needs to be understood first. So what are oxides? Do you remember this from the school curriculum?

Oxides (or oxyls) are binary compounds containing atoms of an electronegative element (less electronegative than oxygen) and oxygen with an oxidation state of -2.

Oxides are incredibly widespread substances on our planet. Examples of oxide compounds: water, rust, some dyes, sand, and even carbon dioxide.

Formation of oxides

Oxides can be obtained by the most different ways... The formation of oxides is also studied by such a science as chemistry. Oxides, their classification and properties - this is what scientists need to know in order to understand how this or that oxide was formed. For example, they can be obtained by direct connection an oxygen atom (or atoms) with a chemical element is the interaction of chemical elements. However, there is also an indirect formation of oxides, this is when oxides are formed by the decomposition of acids, salts or bases.

Classification of oxides

Oxides and their classification depend on how they were formed. According to their classification, oxides are divided into only two groups, the first of which is salt-forming, and the second is non-salt. So, let's take a closer look at both groups.

Salt-forming oxides are a fairly large group that is divided into amphoteric, acidic and basic oxides. As a result of any chemical reaction, salt-forming oxides form salts. As a rule, the composition of salt-forming oxides includes elements of metals and non-metals, which form acids as a result of a chemical reaction with water, but form the corresponding acids and salts when interacting with bases.

Non-salt-forming oxides are oxides that do not form salts as a result of a chemical reaction. Examples of such oxides include carbon.

Amphoteric oxides

Oxides, their classification and properties are very important concepts in chemistry. The composition of the salt-forming includes amphoteric oxides.

Amphoteric oxides are those oxides that can exhibit basic or acidic properties, depending on the conditions of chemical reactions (exhibit amphotericity). Such oxides are formed by transition metals (copper, silver, gold, iron, ruthenium, tungsten, rutherfordium, titanium, yttrium, and many others). Amphoteric oxides react with strong acids, and as a result of a chemical reaction, they form salts of these acids.

Acidic oxides

Or anhydrides - these are oxides that in chemical reactions show and also form oxygen-containing acids. Anhydrides are always formed by typical non-metals as well as some transitional chemical elements.

Oxides, their classification and chemical properties are important concepts. For example, the chemical properties of acidic oxides are completely different from amphoteric ones. For example, when an anhydride interacts with water, the corresponding acid is formed (the exception is SiO2 - Anhydrides interact with alkalis, and as a result of such reactions, water and soda are released. When interacting with, salt is formed.

Basic oxides

Basic (from the word "base") oxides are oxides of chemical elements of metals with oxidation states +1 or +2. These include alkali, alkaline earth metals, and the chemical element magnesium. Basic oxides differ from others in that they are able to react with acids.

Basic oxides interact with acids, unlike acidic oxides, as well as with alkalis, water, and other oxides. As a result of these reactions, salts are usually formed.

Properties of oxides

If you carefully study the reactions of various oxides, you can independently draw conclusions about what chemical properties the oxyls are endowed with. The general chemical property of absolutely all oxides is the redox process.

But nevertheless, all oxides are different from each other. The classification and properties of oxides are two interrelated topics.

Non-salt-forming oxides and their chemical properties

Non-salt-forming oxides are a group of oxides that exhibit neither acidic, nor basic, nor amphoteric properties. As a result of chemical reactions with non-salt-forming oxides, no salts are formed. Previously, such oxides were called not salt-forming, but indifferent and indifferent, but such names do not correspond to the properties of non-salt-forming oxides. By their properties, these oxides are quite capable of chemical reactions. But there are very few non-salt-forming oxides; they are formed by monovalent and divalent non-metals.

Salt-forming oxides can be produced from non-salt-forming oxides by chemical reaction.

Nomenclature

Almost all oxides are usually called like this: the word "oxide", followed by the name chemical element in the genitive case. For example, Al2O3 is aluminum oxide. In chemical language, this oxide reads like this: aluminum 2 about 3. Some chemical elements, such as copper, can have several degrees of oxidation, respectively, the oxides will also be different. Then CuO oxide is copper oxide (two), that is, with an oxidation degree of 2, and Cu2O oxide is a copper oxide (three), which has an oxidation degree of 3.

But there are other names for oxides, which are distinguished by the number of oxygen atoms in the compound. Monoxide or monoxide refers to such oxides, which contain only one oxygen atom. Dioxides are oxyls that contain two oxygen atoms, as indicated by the prefix "di". Trioxides are those oxides that already contain three oxygen atoms. Names such as monoxide, dioxide and trioxide are outdated, but are often found in textbooks, books, and other manuals.

There are also so-called trivial names for oxides, that is, those that have developed historically. For example, CO is carbon monoxide or carbon monoxide, but even chemists most often call this substance carbon monoxide.

So, oxide is a combination of oxygen with a chemical element. The main science that studies their formation and interactions is chemistry. Oxides, their classification and properties are several important topics in the science of chemistry, without understanding which it is impossible to understand everything else. Oxides are gases, minerals and powders. Some oxides are worth knowing in detail not only for scientists, but also ordinary people, because they can even be dangerous to life on this earth. Oxides is a very interesting and fairly easy topic. Oxide compounds are very common in everyday life.

Non-salt-forming (indifferent, indifferent) oxides CO, SiO, N 2 0, NO.

Salt-forming oxides:

Basic. Oxides, hydrates of which are bases. Metal oxides with oxidation states +1 and +2 (rarely +3). Examples: Na 2 O - sodium oxide, CaO - calcium oxide, CuO - copper (II) oxide, CoO - cobalt (II) oxide, Bi 2 O 3 - bismuth (III) oxide, Mn 2 O 3 - manganese oxide (III ).

Amphoteric. Oxides whose hydrates are amphoteric hydroxides. Metal oxides with oxidation states +3 and +4 (rarely +2). Examples: Al 2 O 3 - aluminum oxide, Cr 2 O 3 - chromium (III) oxide, SnO 2 - tin (IV) oxide, MnO 2 - manganese (IV) oxide, ZnO - zinc oxide, BeO - beryllium oxide.

Acidic. Oxides, hydrates of which are oxygen-containing acids. Nonmetal oxides. Examples: P 2 O 3 - phosphorus (III) oxide, CO 2 - carbon monoxide (IV), N 2 O 5 - nitrogen oxide (V), SO 3 - sulfur oxide (VI), Cl 2 O 7 - chlorine oxide ( VII). Metal oxides with oxidation states +5, +6 and +7. Examples: Sb 2 O 5 - antimony (V) oxide. CrOz - chromium (VI) oxide, MnOz - manganese (VI) oxide, Mn 2 O 7 - manganese (VII) oxide.

Change in the nature of oxides with an increase in the oxidation state of the metal

Physical properties

Oxides are solid, liquid and gaseous, of various colors. For example: copper (II) oxide CuO black, calcium oxide CaO white- solids. Sulfur oxide (VI) SO 3 is a colorless volatile liquid, and carbon monoxide (IV) CO 2 is a colorless gas under normal conditions.

State of aggregation

CaO, CuO, Li 2 O and other basic oxides; ZnO, Al 2 O 3, Cr 2 O 3 and other amphoteric oxides; SiO 2, P 2 O 5, CrO 3 and other acidic oxides.

SO 3, Cl 2 O 7, Mn 2 O 7, etc.

Gaseous:

CO 2, SO 2, N 2 O, NO, NO 2, etc.

Water solubility

Soluble:

a) basic oxides of alkali and alkaline earth metals;

b) almost all acidic oxides (exception: SiO 2).

Insoluble:

a) all other basic oxides;

b) all amphoteric oxides

Chemical properties

1. Acid-base properties

The general properties of basic, acidic and amphoteric oxides are acid-base interactions, which are illustrated by the following scheme:

(only for oxides of alkali and alkaline earth metals) (except for SiO 2).

Amphoteric oxides, possessing the properties of both basic and acidic oxides, interact with strong acids and alkalis:

2. Oxidizing - reducing properties

If the item has variable degree oxidation (s. o.), then its oxides with low s. O. can exhibit reducing properties, and oxides with high c. O. - oxidative.

Examples of reactions in which oxides act as reducing agents:

Oxidation of oxides with low c. O. to oxides with high c. O. elements.

2C +2 O + O 2 = 2C +4 O 2

2S +4 O 2 + O 2 = 2S +6 O 3

2N +2 O + O 2 = 2N +4 O 2

Carbon monoxide (II) reduces metals from their oxides and hydrogen from water.

C +2 O + FeO = Fe + 2C +4 O 2

C +2 O + H 2 O = H 2 + 2C +4 O 2

Examples of reactions in which oxides act as oxidizing agents:

Reduction of oxides with high o. elements to oxides with low c. O. or to simple substances.

C +4 O 2 + C = 2C +2 O

2S +6 O 3 + H 2 S = 4S +4 O 2 + H 2 O

C +4 O 2 + Mg = C 0 + 2MgO

Cr +3 2 O 3 + 2Al = 2Cr 0 + 2Al 2 O 3

Cu +2 O + H 2 = Cu 0 + H 2 O

The use of oxides of low-activity metals for the oxidation of organic substances.

Some oxides in which the element has an intermediate c. o., capable of disproportionation;

for example:

2NO 2 + 2NaOH = NaNO 2 + NaNO 3 + H 2 O

Methods of obtaining

1. Interaction of simple substances - metals and non-metals - with oxygen:

4Li + O 2 = 2Li 2 O;

2Cu + O 2 = 2CuO;

4P + 5O 2 = 2P 2 O 5

2. Dehydration of insoluble bases, amphoteric hydroxides and some acids:

Cu (OH) 2 = CuO + H 2 O

2Al (OH) 3 = Al 2 O 3 + 3H 2 O

H 2 SO 3 = SO 2 + H 2 O

H 2 SiO 3 = SiO 2 + H 2 O

3. Decomposition of some salts:

2Cu (NO 3) 2 = 2CuO + 4NO 2 + O 2

CaCO 3 = CaO + CO 2

(CuOH) 2 CO 3 = 2CuO + CO 2 + H 2 O

4. Oxidation of complex substances with oxygen:

CH 4 + 2O 2 = CO 2 + H 2 O

4FeS 2 + 11O 2 = 2Fe 2 O 3 + 8SO 2

4NH 3 + 5O 2 = 4NO + 6H 2 O

5.Reduction of oxidizing acids with metals and non-metals:

Cu + H 2 SO 4 (conc) = CuSO 4 + SO 2 + 2H 2 O

10HNO 3 (conc) + 4Ca = 4Ca (NO 3) 2 + N 2 O + 5H 2 O

2HNO 3 (decomp) + S = H 2 SO 4 + 2NO

6. Interconversions of oxides in the course of redox reactions (see redox properties of oxides).

Acidic oxides Is a fairly large group of complex substances that react with alkalis. In this case, the formation of salts occurs. But they do not interact with acids.

Acidic oxides are formed predominantly by non-metals. For example, this group includes sulfur, phosphorus and chlorine. In addition, substances with the same properties can be formed from the so-called transition elements with a valence of five to seven.

Acidic oxides can form acids when interacting with water. Each has a corresponding oxide. For example, sulfur oxides form sulfate and sulfite acids, and phosphorus - ortho- and metaphosphate acids.

Acidic oxides and methods for their preparation

There are several basic methods with

The most common method is the oxidation of nonmetal atoms with oxygen. For example, when phosphorus interacts with oxygen, phosphorus oxide is obtained. Of course, this method is not always possible.

Another fairly common reaction is the so-called oxygen sulfide roasting. In addition, oxides are obtained by the reaction of certain salts with acids.

Sometimes a slightly different technique is used in laboratories. During the reaction, water is taken away from the corresponding acid - a dehydration process takes place. By the way, this is why acidic oxides are also known under another name - acid anhydrides.

Chemical properties of acidic oxides

As already mentioned, anhydrides can interact with basic oxides or alkalis. As a result of this reaction, a salt of the corresponding acid is formed, and in the reaction with a base, water is also formed. It is this process that characterizes the basic acidic properties of oxides. In addition, anhydrides do not interact with acids.

Another property of these substances is the ability to react with amphoteric bases and oxides. Salts are also formed as a result of this process.

In addition, some anhydrides react with water. As a result of this process, the formation of the corresponding acid is observed. In this way, in laboratory conditions, for example, sulfuric acid is obtained.

The most common anhydrides are: a brief description of

The most common and well-known acidic oxide is carbon dioxide. This substance under normal conditions is a colorless, odorless gas, but with a slight sour taste.

By the way, at atmospheric pressure, carbon dioxide can exist either in a gaseous or in a solid state. In order to convert carbon anhydride into a liquid, it is necessary to increase the pressure. It is this property that is used to store a substance.

Carbon dioxide belongs to the group of greenhouse gases, because it actively absorbs those emitted by the earth while retaining heat in the atmosphere. However, this substance is very important for the life of organisms. Carbon dioxide is found in the atmosphere of our planet. In addition, it is used by plants in the processes of photosynthesis.

Sulfuric anhydride, or sulfur trioxide, is another representative of this group of substances. Under normal conditions, it is a colorless, highly volatile liquid with an unpleasant, suffocating odor. This oxide is very important in chemical industry, since the bulk of sulfuric acid is produced from it.

Silicon oxide is another fairly well-known substance, which in its normal state is crystals. By the way, sand consists of this compound. when heated, it can melt and solidify. This property is used in the production of glass. In addition, the substance practically does not conduct electricity, so I use it as a dielectric.

Modern encyclopedia

Oxides- OXIDES, compounds of chemical elements (except fluorine) with oxygen. When interacting with water, they form bases (basic oxides) or acids (acidic oxides), many oxides are amphoteric. Most oxides are solids under normal conditions, ... ... Illustrated Encyclopedic Dictionary

Oxide (oxide, oxide) is a binary compound of a chemical element with oxygen in the oxidation state −2, in which oxygen itself is bound only to a less electronegative element. The chemical element oxygen is second in electronegativity ... ... Wikipedia

Metal oxides are compounds of metals with oxygen. Many of them can combine with one or more water molecules to form hydroxides. Most oxides are basic because their hydroxides behave like bases. However, some ... ... Official terminology

oxides- The combination of a chemical element with oxygen. According to their chemical properties, all oxides are divided into salt-forming (for example, Na2O, MgO, Al2O3, SiO2, P2O5, SO3, Cl2O7) and non-salt-forming (for example, CO, N2O, NO, H2O). Salt-forming oxides are divided into ... ... Technical translator's guide

OXIDES- chem. compounds of elements with oxygen (the old name is oxides); one of the most important classes of chem. substances. O. are formed most often during the direct oxidation of simple and complex substances. Ex. during the oxidation of hydrocarbons, O. are formed ... ... Big Polytechnic Encyclopedia

Key facts

Key facts- Oil is flammable liquid, which is a complex mixture of hydrocarbons. Various types oils differ significantly in chemical and physical properties: in nature it is presented both in the form of black bituminous asphalt, and in the form of ... ... Oil and gas microencyclopedia

Key facts- Oil is a flammable liquid, which is a complex mixture of hydrocarbons. Different types of oil differ significantly in chemical and physical properties: in nature, it is presented in the form of black bituminous asphalt, and in the form ... ... Oil and gas microencyclopedia

Oxides- the combination of a chemical element with oxygen. According to their chemical properties, all oxides are divided into salt-forming (for example, Na2O, MgO, Al2O3, SiO2, P2O5, SO3, Cl2O7) and non-salt-forming (for example, CO, N2O, NO, H2O). Salt-forming oxides ... ... encyclopedic Dictionary for metallurgy

Books

• , Gusev Alexander Ivanovich. Nonstoichiometry due to the presence of structural vacancies is widespread in solid-phase compounds and creates the preconditions for a disordered or ordered distribution ...
• Nonstoichiometry, disorder, short-range and long-range order in a solid, Gusev AI .. Nonstoichiometry due to the presence of structural vacancies is widespread in solid-phase compounds and creates preconditions for a disordered or ordered distribution ...

Lesson 32 “ Chemical properties of oxides"From the course" Chemistry for dummies»Learn about all the chemical properties of acidic and basic oxides, consider what they react with and what is formed in this case.

Because chemical composition acidic and basic oxides are different, they differ in their chemical properties.

1. Chemical properties of acid oxides

a) Interaction with water
You already know that the products of the interaction of oxides with water are called "hydroxides":

Since the oxides that enter into this reaction are divided into acidic and basic, the hydroxides formed from them are also divided into acidic and basic. Thus, acidic oxides (other than SiO 2) react with water to form acidic hydroxides, which are oxygen-containing acids:

Each acidic oxide corresponds to an oxygen-containing acid related to acidic hydroxides. Despite the fact that silicon oxide SiO 2 does not react with water, it also corresponds to the acid H 2 SiO 3, but it is obtained by other methods.

b) Interaction with alkalis
All acidic oxides react with alkalis according to the general scheme:

In the resulting salt, the valence of the metal atoms is the same as in the initial alkali. Besides, the composition of the salt contains the remainder of the acid that corresponds to the given acidic oxide.

For example, if an acidic oxide CO 2 enters into the reaction, which corresponds to an acid H 2 CO 3 CO 3, the valency of which, as you already know, is equal to II:

If the acidic oxide N 2 O 5 enters into the reaction, to which the acid H NO 3(indicated in square brackets), then the resulting salt will contain the remainder of this acid - NO 3 with valency equal to I:

Since all acidic oxides react with alkalis to form salts and water, these oxides can be defined differently.

Acidic are called oxides that react with alkalis to form salts and water.

c) Reactions with basic oxides

Acidic oxides react with basic oxides to form salts in accordance with the general scheme:

In the resulting salt, the valence of the metal atoms is the same as in the initial basic oxide. It should be remembered that the composition of the salt contains the remainder of the acid that corresponds to the acidic oxide that reacts. For example, if an acidic oxide SO 3 enters into the reaction, which corresponds to an acid H 2 SO 4(indicated in square brackets), then the composition of the salt will include the remainder of this acid - SO 4, whose valency is II:

If acidic oxide Р 2 О 5 enters into the reaction, which corresponds to acid Н 3 RO 4, then the resulting salt will contain the remainder of this acid - PO 4 with a valency equal to III.

2. Chemical properties of basic oxides

a) Interaction with water

You already know that as a result of the interaction of basic oxides with water, basic hydroxides are formed, which are otherwise called bases:

These basic oxides include oxides: Li 2 O, Na 2 O, K 2 O, CaO, BaO.

When writing the equations of the corresponding reactions, it should be remembered that the valence of the metal atoms in the resulting base is equal to its valence in the initial oxide.

Basic oxides formed by metals such as Cu, Fe, Cr do not react with water. The corresponding grounds are obtained in other ways.

b) Interaction with acids

Almost all basic oxides react with acids to form salts according to the general scheme:

It should be remembered that in the resulting salt, the valence of the metal atoms is the same as in the initial oxide, and the valence of the acid residue is the same as in the initial acid.

Since all basic oxides react with acids to form salts and water, these oxides can be defined differently.

The main are called oxides that react with acids to form salts and water.

c) Interaction with acid oxides

Basic oxides react with acidic oxides to form salts in accordance with the general scheme:

In the resulting salt, the valence of the metal atoms is the same as in the initial basic oxide. Also, you should remember that the composition of the salt contains the remainder of the acid that corresponds to the acidic oxide that reacts... For example, if an acidic oxide N 2 O 5 enters into the reaction, to which the acid H NO 3, then the composition of the salt will include the remainder of this acid - NO 3, whose valency, as you already know, is I.

Since the acidic and basic oxides considered by us form salts as a result of various reactions, they are called salt-forming... There is, however, a small group of oxides that do not form salts in similar reactions, which is why they are called non-salt-forming.

Lesson summary:

1. All acidic oxides react with alkalis to form salts and water.
2. All basic oxides react with acids to form salts and water.
3. Acidic and basic oxides are salt-forming. Non-salt-forming oxides - CO, N 2 O, NO.
4. Bases and oxygenated acids are hydroxides.

Hopefully lesson 32 " Chemical properties of oxides”Was understandable and informative. If you have any questions, write them in the comments.