K2o basic. What are oxides

Oxides are inorganic compounds consisting of two chemical elements, one of which is oxygen in the -2 oxidation state. The only one an element that does not form an oxide is fluorine, which combines with oxygen to form oxygen fluoride. This is due to the fact that fluorine is a more electronegative element than oxygen.

This class of compounds is very common. Every day a person encounters a variety of oxides in everyday life. Water, sand, carbon dioxide we exhale, car exhaust, rust are all examples of oxides.

Oxides classification

All oxides, according to their ability to form salts, can be divided into two groups:

Salt-forming oxides (CO 2, N 2 O 5, Na 2 O, SO 3, etc.)
Non-salt-forming oxides (CO, N 2 O, SiO, NO, etc.)

In turn, salt-forming oxides are divided into 3 groups:

Basic oxides- (Metal oxides - Na 2 O, CaO, CuO, etc.)
Acidic oxides- (Oxides of non-metals, as well as metal oxides in the oxidation state V-VII - Mn 2 O 7, CO 2, N 2 O 5, SO 2, SO 3, etc.)
(Metal oxides with oxidation state III-IV as well as ZnO, BeO, SnO, PbO)

This classification is based on the manifestation of certain chemical properties by oxides. So, basic oxides correspond to bases, and acidic oxides correspond to acids. Acidic oxides react with basic oxides to form the corresponding salt, as if the base and acid corresponding to these oxides reacted: Likewise, Amphoteric bases correspond to amphoteric oxides, which can exhibit both acidic and basic properties: Chemical elements exhibiting different degrees of oxidation can form various oxides. In order to somehow distinguish the oxides of such elements, after the name of the oxide, the valence is indicated in parentheses.

CO 2 – carbon monoxide (IV)

N 2 O 3 – nitric oxide (III)

Physical properties of oxides

Oxides are very diverse in their physical properties. They can be either liquids (H 2 O), gases (CO 2, SO 3) or solids (Al 2 O 3, Fe 2 O 3). Moreover, basic oxides are usually solids. Oxides also have a wide variety of colors - from colorless (H 2 O, CO) and white (ZnO, TiO 2) to green (Cr 2 O 3) and even black (CuO).

Basic oxides

Some oxides react with water to form the corresponding hydroxides (bases): Basic oxides react with acidic oxides to form salts: They react similarly with acids, but with the release of water: Oxides of metals less active than aluminum can be reduced to metals:

Acidic oxides

Acidic oxides react with water to form acids: Some oxides (for example, silicon oxide SiO2) do not react with water, so acids are obtained in other ways.

Acidic oxides interact with basic oxides, forming salts: In the same way, with the formation of salts, acidic oxides react with bases: If a polybasic acid corresponds to a given oxide, then an acidic salt can also form: Non-volatile acid oxides can replace volatile oxides in salts:

As mentioned earlier, amphoteric oxides, depending on conditions, can exhibit both acidic and basic properties. So they act as basic oxides in reactions with acids or acidic oxides, forming salts: And in reactions with bases or basic oxides they exhibit acidic properties:

Obtaining oxides

Oxides can be obtained in a variety of ways; we will present the main ones.

Most oxides can be obtained by direct interaction of oxygen with a chemical element: When roasting or burning various binary compounds: Thermal decomposition of salts, acids and bases: Interaction of some metals with water:

Application of oxides

Oxides are extremely common throughout the globe and are used both in everyday life and in industry. The most important oxide, hydrogen oxide, water, made life on Earth possible. Sulfur oxide SO 3 is used to produce sulfuric acid, as well as for processing food products - this increases the shelf life of, for example, fruits.

Iron oxides are used to obtain paints and produce electrodes, although most iron oxides are reduced to metallic iron in metallurgy.

Calcium oxide, also known as quicklime, is used in construction. Zinc and titanium oxides are white and insoluble in water, which is why they have become good materials for the production of paints - white.

Silicon oxide SiO 2 is the main component of glass. Chromium oxide Cr 2 O 3 is used for the production of colored green glasses and ceramics, and due to its high strength properties, for polishing products (in the form of GOI paste).

Carbon monoxide CO 2, which is released by all living organisms when breathing, is used for fire extinguishing, and also, in the form of dry ice, to cool something.

Oxides.

These are complex substances consisting of TWO elements, one of which is oxygen. For example:

CuO – copper(II) oxide

AI 2 O 3 – aluminum oxide

SO 3 – sulfur oxide (VI)

Oxides are divided (classified) into 4 groups:

Na 2 O– Sodium oxide

CaO – Calcium Oxide

Fe 2 O 3 – iron (III) oxide

2). Acidic– These are oxides non-metals. And sometimes metals if the oxidation state of the metal is > 4. For example:

CO 2 – Carbon monoxide (IV)

P 2 O 5 – Phosphorus (V) oxide

SO 3 – Sulfur oxide (VI)

3). Amphoteric– These are oxides that have the properties of both basic and acidic oxides. You need to know the five most common amphoteric oxides:

BeO–beryllium oxide

ZnO–zinc oxide

AI 2 O 3 – Aluminum oxide

Cr 2 O 3 – Chromium (III) oxide

Fe 2 O 3 – Iron (III) oxide

4). Non-salt-forming (indifferent)– These are oxides that do not exhibit the properties of either basic or acidic oxides. There are three oxides to remember:

CO – carbon monoxide (II) carbon monoxide

NO – nitric oxide (II)

N 2 O – nitric oxide (I) laughing gas, nitrous oxide

Methods for producing oxides.

1). Combustion, i.e. interaction with oxygen of a simple substance:

4Na + O 2 = 2Na 2 O

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

2). Combustion, i.e. interaction with oxygen of a complex substance (consisting of two elements) thus forming two oxides.

2ZnS + 3O 2 = 2ZnO + 2SO 2

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

3). Decomposition three weak acids. Others do not decompose. In this case, acid oxide and water are formed.

H 2 CO 3 = H 2 O + CO 2

H 2 SO 3 = H 2 O + SO 2

H 2 SiO 3 = H 2 O + SiO 2

4). Decomposition insoluble grounds. A basic oxide and water are formed.

Mg(OH) 2 = MgO + H 2 O

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

5). Decomposition insoluble salts A basic oxide and an acidic oxide are formed.

CaCO 3 = CaO + CO 2

MgSO 3 = MgO + SO 2

Chemical properties.

I. Basic oxides.

alkali.

Na 2 O + H 2 O = 2NaOH

CaO + H 2 O = Ca(OH) 2

СuO + H 2 O = the reaction does not occur, because possible base containing copper - insoluble

2). Interaction with acids, resulting in the formation of salt and water. (Base oxide and acids ALWAYS react)

K 2 O + 2HCI = 2KCl + H 2 O

CaO + 2HNO 3 = Ca(NO 3) 2 + H 2 O

3). Interaction with acidic oxides, resulting in the formation of salt.

Li 2 O + CO 2 = Li 2 CO 3

3MgO + P 2 O 5 = Mg 3 (PO 4) 2

4). Interaction with hydrogen produces metal and water.

CuO + H 2 = Cu + H 2 O

Fe 2 O 3 + 3H 2 = 2Fe + 3H 2 O

II.Acidic oxides.

1). Interaction with water should form acid.(OnlySiO 2 does not interact with water)

CO 2 + H 2 O = H 2 CO 3

P 2 O 5 + 3H 2 O = 2H 3 PO 4

2). Interaction with soluble bases (alkalis). This produces salt and water.

SO 3 + 2KOH = K 2 SO 4 + H 2 O

N 2 O 5 + 2KOH = 2KNO 3 + H 2 O

3). Interaction with basic oxides. In this case, only salt is formed.

N 2 O 5 + K 2 O = 2KNO 3

Al 2 O 3 + 3SO 3 = Al 2 (SO 4) 3

Basic exercises.

1). Complete the reaction equation. Determine its type.

K 2 O + P 2 O 5 =

Solution.

To write down what is formed as a result, it is necessary to determine what substances have reacted - here it is potassium oxide (basic) and phosphorus oxide (acidic) according to the properties - the result should be SALT (see property No. 3) and salt consists of atoms metals (in our case potassium) and an acidic residue which includes phosphorus (i.e. PO 4 -3 - phosphate) Therefore

3K 2 O + P 2 O 5 = 2K 3 RO 4

type of reaction - compound (since two substances react, but one is formed)

2). Carry out transformations (chain).

Ca → CaO → Ca(OH) 2 → CaCO 3 → CaO

Solution

To complete this exercise, you must remember that each arrow is one equation (one chemical reaction). Let's number each arrow. Therefore, it is necessary to write down 4 equations. The substance written to the left of the arrow (starting substance) reacts, and the substance written to the right is formed as a result of the reaction (reaction product). Let's decipher the first part of the recording:

Ca + …..→ CaO We note that a simple substance reacts and an oxide is formed. Knowing the methods for producing oxides (No. 1), we come to the conclusion that in this reaction it is necessary to add -oxygen (O 2)

2Ca + O 2 → 2CaO

Let's move on to transformation No. 2

CaO → Ca(OH) 2

CaO + ……→ Ca(OH) 2

We come to the conclusion that here it is necessary to apply the property of basic oxides - interaction with water, because only in this case a base is formed from the oxide.

CaO + H 2 O → Ca(OH) 2

Let's move on to transformation No. 3

Ca(OH) 2 → CaCO 3

Ca(OH) 2 + ….. = CaCO 3 + …….

We come to the conclusion that here we are talking about carbon dioxide CO 2 because only when interacting with alkalis it forms a salt (see property No. 2 of acid oxides)

Ca(OH) 2 + CO 2 = CaCO 3 + H 2 O

Let's move on to transformation No. 4

CaCO 3 → CaO

CaCO 3 = ….. CaO + ……

We come to the conclusion that more CO 2 is formed here, because CaCO 3 is an insoluble salt and it is during the decomposition of such substances that oxides are formed.

CaCO 3 = CaO + CO 2

3). Which of the following substances does CO 2 interact with? Write the reaction equations.

A). Hydrochloric acid B). Sodium hydroxide B). Potassium oxide d). Water

D). Hydrogen E). Sulfur(IV) oxide.

We determine that CO 2 is an acidic oxide. And acidic oxides react with water, alkalis and basic oxides... Therefore, from the list above, we select answers B, C, D And it is with them that we write down the reaction equations:

1). CO 2 + 2NaOH = Na 2 CO 3 + H 2 O

2). CO 2 + K 2 O = K 2 CO 3

If you weren't interested in chemistry at school, you're unlikely to immediately remember what oxides are and what their role is in the environment. It is actually a fairly common type of compound and is most commonly found in the environment in the form of water, rust, carbon dioxide and sand. Oxides also include minerals - a type of rock that has a crystalline structure.

Definition

Oxides are chemical compounds whose formula contains at least one oxygen atom and atoms of other chemical elements. Metal oxides typically contain oxygen anions in the -2 oxidation state. A significant part of the Earth's crust consists of solid oxides that arose during the oxidation of elements with oxygen from air or water. When a hydrocarbon is burned, two main oxides of carbon are produced: carbon monoxide (carbon monoxide, CO) and carbon dioxide (carbon dioxide, CO2).

Oxides classification

All oxides are usually divided into two large groups:

salt-forming oxides;
non-salt-forming oxides.

Salt-forming oxides are chemical substances that, in addition to oxygen, contain elements of metals and non-metals, which form acids upon contact with water, and when combined with bases - salts.

Salt-forming oxides, in turn, are divided into:

basic oxides in which, upon oxidation, the second element (1, 2 and sometimes 3-valent metal) becomes a cation (Li 2 O, Na 2 O, K 2 O, CuO, Ag 2 O, MgO, CaO, SrO, BaO, HgO , MnО, CrO, NiО, Fr 2 O, Cs 2 O, Rb 2 O, FeO);
acid oxides in which, during the formation of a salt, a second element is attached to a negatively charged oxygen atom (CO 2, SO 2, SO 3, SiO 2, P 2 O 5, CrO 3, Mn 2 O 7, NO 2, Cl 2 O 5, Cl 2 O 3);
amphoteric oxides in which a second element (3 and 4 valent metals or exceptions such as zinc oxide, beryllium oxide, tin oxide and lead oxide) can become either a cation or join an anion (ZnO, Cr 2 O 3, Al 2 O 3, SnO, SnO 2, PbO, PbO 2, TiO 2, MnO 2, Fe 2 O 3, BeO).

Non-salt-forming oxides exhibit neither acidic, basic, nor amphoteric properties and, as the name implies, do not form salts (CO, NO, NO 2, (FeFe 2)O 4).

Properties of oxides

Oxygen atoms in oxides have high chemical activity. Due to the fact that the oxygen atom is always negatively charged, it forms stable chemical bonds with almost all elements, which leads to a wide variety of oxides.
Noble metals such as gold and platinum are valued because they do not oxidize naturally. Corrosion of metals occurs as a result of hydrolysis or oxidation with oxygen. The combination of water and oxygen only speeds up the reaction rate.
In the presence of water and oxygen (or just air), the oxidation reaction of some elements, for example, sodium, occurs rapidly and can be dangerous to humans.
Oxides create a protective oxide film on the surface. An example is aluminum foil, which, due to its coating of a thin film of aluminum oxide, corrodes much more slowly.
The oxides of most metals have a polymer structure, so they are not destroyed by solvents.
Oxides dissolve under the action of acids and bases. Oxides that can react with both acids and bases are called amphoteric. Metals typically form basic oxides, nonmetals form acidic oxides, and amphoteric oxides are produced from alkali metals (metalloids).
The amount of metal oxide can be reduced by the action of certain organic compounds. These redox reactions underlie many important chemical transformations, such as the detoxification of drugs by P450 enzymes and the production of ethylene oxide, which is then used to make antifreeze.

Those who are interested in chemistry will also be interested in the following articles.

1. Metal + Non-metal. Inert gases do not enter into this interaction. The higher the electronegativity of a nonmetal, the more metals it will react with. For example, fluorine reacts with all metals, and hydrogen only with active ones. The further to the left a metal is in the metal activity series, the more nonmetals it can react with. For example, gold reacts only with fluorine, lithium - with all non-metals.

2. Non-metal + non-metal. In this case, a more electronegative nonmetal acts as an oxidizing agent, and a less electronegative nonmetal acts as a reducing agent. Nonmetals with similar electronegativity interact poorly with each other, for example, the interaction of phosphorus with hydrogen and silicon with hydrogen is practically impossible, since the equilibrium of these reactions is shifted towards the formation of simple substances. Helium, neon and argon do not react with non-metals; other inert gases can react with fluorine under harsh conditions.
Oxygen does not interact with chlorine, bromine and iodine. Oxygen can react with fluorine at low temperatures.

3. Metal + acid oxide. The metal reduces the nonmetal from the oxide. The excess metal can then react with the resulting nonmetal. For example:

2 Mg + SiO 2 = 2 MgO + Si (with magnesium deficiency)

2 Mg + SiO 2 = 2 MgO + Mg 2 Si (with excess magnesium)

4. Metal + acid. Metals located in the voltage series to the left of hydrogen react with acids to release hydrogen.

The exception is oxidizing acids (concentrated sulfur and any nitric acid), which can react with metals that are in the voltage series to the right of hydrogen; in the reactions, hydrogen is not released, but water and the acid reduction product are obtained.

It is necessary to pay attention to the fact that when a metal reacts with an excess of a polybasic acid, an acid salt can be obtained: Mg +2 H 3 PO 4 = Mg (H 2 PO 4 ) 2 + H 2 .

If the product of the interaction between an acid and a metal is an insoluble salt, then the metal is passivated, since the surface of the metal is protected by the insoluble salt from the action of the acid. For example, the effect of dilute sulfuric acid on lead, barium or calcium.

5. Metal + salt. In solution This reaction involves metals that are in the voltage series to the right of magnesium, including magnesium itself, but to the left of the metal salt. If the metal is more active than magnesium, then it reacts not with salt, but with water to form an alkali, which subsequently reacts with salt. In this case, the original salt and the resulting salt must be soluble. The insoluble product passivates the metal.

However, there are exceptions to this rule:

2FeCl 3 + Cu = CuCl 2 + 2FeCl 2;

2FeCl 3 + Fe = 3FeCl 2. Since iron has an intermediate oxidation state, its salt in the highest oxidation state is easily reduced to a salt in the intermediate oxidation state, oxidizing even less active metals.

In meltsa number of metal stresses are not effective. Determining whether a reaction between a salt and a metal is possible can only be done using thermodynamic calculations. For example, sodium can displace potassium from a potassium chloride melt, since potassium is more volatile: Na + KCl = NaCl + K (this reaction is determined by the entropy factor). On the other hand, aluminum was obtained by displacement from sodium chloride: 3 Na + AlCl 3 = 3 NaCl + Al . This process is exothermic and is determined by the enthalpy factor.

It is possible that the salt decomposes when heated, and the products of its decomposition can react with the metal, for example, aluminum nitrate and iron. Aluminum nitrate decomposes when heated into aluminum oxide, nitric oxide ( IV ) and oxygen, oxygen and nitric oxide will oxidize iron:

10Fe + 2Al(NO 3) 3 = 5Fe 2 O 3 + Al 2 O 3 + 3N 2

6. Metal + basic oxide. Just as in molten salts, the possibility of these reactions is determined thermodynamically. Aluminum, magnesium and sodium are often used as reducing agents. For example: 8 Al + 3 Fe 3 O 4 = 4 Al 2 O 3 + 9 Fe exothermic reaction, enthalpy factor);2 Al + 3 Rb 2 O = 6 Rb + Al 2 O 3 (volatile rubidium, enthalpy factor).

8. Non-metal + base. As a rule, the reaction occurs between a non-metal and an alkali. Not all non-metals can react with alkalis: you need to remember that halogens (in different ways depending on temperature), sulfur (when heated), silicon, phosphorus enter into this interaction.

KOH + Cl 2 = KClO + KCl + H 2 O (in the cold)

6 KOH + 3 Cl 2 = KClO 3 + 5 KCl + 3 H 2 O (in hot solution)

6KOH + 3S = K 2 SO 3 + 2K 2 S + 3H 2 O

2KOH + Si + H 2 O = K 2 SiO 3 + 2H 2

3KOH + 4P + 3H 2 O = PH 3 + 3KPH 2 O 2

1) non-metal – reducing agent (hydrogen, carbon):

CO 2 + C = 2CO;

2NO 2 + 4H 2 = 4H 2 O + N 2;

SiO 2 + C = CO 2 + Si. If the resulting non-metal can react with the metal used as a reducing agent, then the reaction will go further (with an excess of carbon) SiO 2 + 2 C = CO 2 + Si C

2) non-metal – oxidizing agent (oxygen, ozone, halogens):

2С O + O 2 = 2СО 2.

C O + Cl 2 = CO Cl 2.

2 NO + O 2 = 2 N O 2.

10. Acidic oxide + basic oxide . The reaction occurs if the resulting salt exists in principle. For example, aluminum oxide can react with sulfuric anhydride to form aluminum sulfate, but cannot react with carbon dioxide because the corresponding salt does not exist.

11. Water + basic oxide . The reaction is possible if an alkali is formed, that is, a soluble base (or slightly soluble, in the case of calcium). If the base is insoluble or slightly soluble, then the reverse reaction of decomposition of the base into oxide and water occurs.

12. Basic oxide + acid . The reaction is possible if the resulting salt exists. If the resulting salt is insoluble, the reaction may be passivated due to the blocking of acid access to the oxide surface. In case of excess polybasic acid, the formation of an acid salt is possible.

13. Acid oxide + base. Typically, the reaction occurs between an alkali and an acidic oxide. If an acid oxide corresponds to a polybasic acid, an acid salt can be obtained: CO 2 + KOH = KHCO 3.

Acidic oxides, corresponding to strong acids, can also react with insoluble bases.

Sometimes oxides corresponding to weak acids react with insoluble bases, which can result in a medium or basic salt (as a rule, a less soluble substance is obtained): 2 Mg (OH) 2 + CO 2 = (MgOH) 2 CO 3 + H 2 O.

14. Acid oxide + salt. The reaction can occur in a melt or in solution. In the melt, the less volatile oxide displaces the more volatile oxide from the salt. In solution, the oxide corresponding to the stronger acid displaces the oxide corresponding to the weaker acid. For example, Na 2 CO 3 + SiO 2 = Na 2 SiO 3 + CO 2 , in the forward direction, this reaction occurs in the melt, carbon dioxide is more volatile than silicon oxide; in the opposite direction, the reaction occurs in solution, carbonic acid is stronger than silicic acid, and silicon oxide precipitates.

It is possible to combine an acidic oxide with its own salt, for example, dichromate can be obtained from chromate, and disulfate from sulfate, and disulfite from sulfite:

Na 2 SO 3 + SO 2 = Na 2 S 2 O 5

To do this, you need to take a crystalline salt and pure oxide, or a saturated salt solution and an excess of acidic oxide.

In solution, salts can react with their own acid oxides to form acid salts: Na 2 SO 3 + H 2 O + SO 2 = 2 NaHSO 3

15. Water + acid oxide . The reaction is possible if a soluble or slightly soluble acid is formed. If the acid is insoluble or slightly soluble, then a reverse reaction occurs, the decomposition of the acid into oxide and water. For example, sulfuric acid is characterized by a reaction of production from oxide and water, the decomposition reaction practically does not occur, silicic acid cannot be obtained from water and oxide, but it easily decomposes into these components, but carbonic and sulfurous acids can participate in both direct and reverse reactions.

16. Base + acid. A reaction occurs if at least one of the reactants is soluble. Depending on the ratio of the reagents, medium, acidic and basic salts can be obtained.

17. Base + salt. The reaction occurs if both starting substances are soluble, and at least one non-electrolyte or weak electrolyte (precipitate, gas, water) is obtained as a product.

18. Salt + acid. As a rule, a reaction occurs if both starting substances are soluble, and at least one non-electrolyte or weak electrolyte (precipitate, gas, water) is obtained as a product.

A strong acid can react with insoluble salts of weak acids (carbonates, sulfides, sulfites, nitrites), and a gaseous product is released.

Reactions between concentrated acids and crystalline salts are possible if a more volatile acid is obtained: for example, hydrogen chloride can be obtained by the action of concentrated sulfuric acid on crystalline sodium chloride, hydrogen bromide and hydrogen iodide - by the action of orthophosphoric acid on the corresponding salts. You can act with an acid on your own salt to produce an acid salt, for example: BaSO 4 + H 2 SO 4 = Ba (HSO 4 ) 2 .

19. Salt + salt.As a rule, a reaction occurs if both starting substances are soluble, and at least one non-electrolyte or weak electrolyte is obtained as a product.

1) salt does not exist because irreversibly hydrolyzes . These are most carbonates, sulfites, sulfides, silicates of trivalent metals, as well as some salts of divalent metals and ammonium. Trivalent metal salts are hydrolyzed to the corresponding base and acid, and divalent metal salts are hydrolyzed to less soluble basic salts.

Let's look at examples:

2 FeCl 3 + 3 Na 2 CO 3 = Fe 2 ( CO 3 ) 3 + 6 NaCl (1)

Fe 2 (CO 3) 3+ 6H 2 O = 2Fe(OH) 3 + 3 H2CO3

H 2 CO 3 decomposes into water and carbon dioxide, the water in the left and right parts is reduced and the result is: Fe 2 ( CO 3 ) 3 + 3 H 2 O = 2 Fe (OH) 3 + 3 CO 2 (2)

If we now combine (1) and (2) equations and reduce iron carbonate, we obtain a total equation reflecting the interaction of ferric chloride ( III ) and sodium carbonate: 2 FeCl 3 + 3 Na 2 CO 3 + 3 H 2 O = 2 Fe (OH) 3 + 3 CO 2 + 6 NaCl

CuSO 4 + Na 2 CO 3 = CuCO 3 + Na 2 SO 4 (1)

The underlined salt does not exist due to irreversible hydrolysis:

2CuCO3+ H 2 O = (CuOH) 2 CO 3 +CO 2 (2)

If we now combine (1) and (2) equations and reduce copper carbonate, we obtain a total equation reflecting the interaction of sulfate ( II ) and sodium carbonate:

2CuSO 4 + 2Na 2 CO 3 + H 2 O = (CuOH) 2 CO 3 + CO 2 + 2Na 2 SO 4

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

What are oxides?

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

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

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

Formation of oxides

Oxides can be obtained in a variety of 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 directly combining an oxygen atom (or atoms) with a chemical element - this is the interaction of chemical elements. However, there is also indirect formation of oxides, this is when oxides are formed by the decomposition of acids, salts or bases.

Oxides classification

Oxides and their classification depend on how they are 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-forming. So, let's take a closer look at both groups.

Salt-forming oxides are a fairly large group, which 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 when interacting with bases they form the corresponding acids and salts.

Non-salt-forming oxides are those 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 salt-forming compounds includes amphoteric oxides.

Amphoteric oxides are oxides that can exhibit basic or acidic properties, depending on the conditions of chemical reactions (they 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 are oxides that exhibit and also form oxygen-containing acids in chemical reactions. Anhydrides are always formed by typical nonmetals, as well as by some transition chemical elements.

Oxides, their classification and chemical properties are important concepts. For example, acidic oxides have completely different chemical properties from amphoteric oxides. For example, when an anhydride reacts with water, a corresponding acid is formed (the exception is SiO2 - Anhydrides react with alkalis, and as a result of such reactions water and soda are released. When reacting with, a 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 and alkaline earth metals, as well as the chemical element magnesium. Basic oxides differ from others in that they are the ones that 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 oxides are endowed with. A common 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, basic, nor amphoteric properties. As a result of chemical reactions with non-salt-forming oxides, no salts are formed. Previously, such oxides were not called non-salt-forming, but indifferent and indifferent, but such names do not correspond to the properties of non-salt-forming oxides. According to 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 nonmetals.

From non-salt-forming oxides, salt-forming oxides can be obtained as a result of a chemical reaction.

Nomenclature

Almost all oxides are usually called this way: the word “oxide”, followed by the name of the chemical element in the genitive case. For example, Al2O3 is aluminum oxide. In chemical language, this oxide reads like this: aluminum 2 o 3. Some chemical elements, such as copper, can have several degrees of oxidation; accordingly, the oxides will also be different. Then CuO oxide is copper (two) oxide, that is, with an oxidation degree of 2, and Cu2O oxide is copper (three) oxide, 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. Monoxides or monoxides are those oxides that contain only one oxygen atom. Dioxides are those oxides that contain two oxygen atoms, which are indicated by the prefix “di”. Trioxides are those oxides that already contain three oxygen atoms. Names such as monoxide, dioxide and trioxide are already outdated, but are often found in textbooks, books and other aids.

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

So, an oxide is a compound 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 for ordinary people, because they can even be dangerous to life on this earth. Oxides are a very interesting and quite easy topic. Oxide compounds are very common in everyday life.