Oxides are complex substances consisting of two elements, one of which is oxygen in the second oxidation state.

In the chemical literature, the following rules are followed for the nomenclature of oxides:

1. When writing formulas, oxygen is always put in second place - NO, CaO.
2. When naming oxides, the word oxide is always used first, after it in genitive case comes the name of the second element: BaO - barium oxide, K₂O - potassium oxide.
3. In the case when an element forms several oxides, after its name, this element is indicated in brackets, for example N₂O₅ - (V), Fe₂O₃ - iron oxide (II), Fe₂O₃ - iron oxide (III).
4. When naming the most common oxides, it is imperative that the ratios of atoms in a molecule be denoted by the corresponding Greek numerals: N₂O - dinitrogen oxide, NO₂ - nitrogen dioxide, N₂O₅ - dinitrogen pentoxide, NO - nitrogen monoxide.
5. Anhydrides are preferably named exactly like oxides (eg N₂O₅ - (V)).

Oxides can be obtained in several different ways:

1. Interaction with oxygen simple substances. Simple substances are oxidized when heated, often with the release of heat and light. This process is called combustion.
   C + O₂ = CO₂
2. Due to oxidation, oxides of elements are obtained, which are included in the composition of the original substance:
   2H₂S + 3O₂ = 2 H₂O + 2 SO₂
3. Decomposition of nitrates, hydroxides, carbonates:
   2Cu(NO₃)₂ = 2CuO + 4NO₂ + O₂
   CaCO₃ = CaO + CO₂
   Cu(OH)₂ = CuO + H₂O
4. As a result of the oxidation of metals by oxides of other elements. Similar reactions became the basis of metallothermy - the reduction of metals from their oxides using more active metals:
   2Al + Cr₂O₃ = 2Cr ±Al₂O₃
5. By decomposition or additional oxidation of the lower:
   4CrO₃ = 2Cr₂O₃ + 3O₃
   4FeO + O₂ = 2Fe₂O₃
   4CO + O₂ = 2CO₂

The classification of oxides based on their chemical properties implies their division into salt-forming and non-salt-forming oxides (indifferent). Salt-forming oxides, in turn, are divided into acidic, basic and amphoteric.

Basic oxides bases match. For example, Na₂O, CaO, MgO are basic oxides, since they correspond to bases - NaOH, Ca(OH)₂, Mg(OH)₂. Some oxides (K₂O and CaO) easily react with water and form the corresponding bases:

CaO + H₂O = Ca(OH)₂

K₂O + H₂O = 2KOH

Oxides Fe₂O₃, CuO, Ag₂O do not react with water, but neutralize acids, due to which they are considered basic:

Fe₂O₃, + 6HCl = 2FeCl₃ + 3H₂OCuO + H₂SO₄ + H₂O

Ag₂O + 2HNO₃ = 2AgNO₃ + H₂O

Typical Chemical properties oxides of this type - their reaction with acids, as a result of which, as a rule, water and salt are formed:

FeO + 2HCl = FeCl₂ + H₂O

Basic oxides also react with acidic oxides:

CaO + CO₂ = CaCO₃.

Acid oxides correspond to acids, For example, the oxide N₂O₃ corresponds to HNO₂, Cl₂O₇ - HClO₄, SO₃ - sulphuric acid H₂SO₄.

The main chemical property of such oxides is their reaction with bases, salt and water are formed:

2NaOH + CO₂ = NaCO₃ + H₂O

Most acidic oxides react with water to form the corresponding acids. At the same time, SiO₂ oxide is practically insoluble in water, however, it neutralizes bases, therefore, it is an acidic oxide:

2NaOH + SiO₂ = (fusion) Na₂siO₃ + H₂O

Amphoteric oxides- these are oxides, which, depending on the conditions, demonstrate acidic and basic properties, i.e. when interacting with acids, they behave like basic oxides, and when interacting with bases, they behave like acidic ones.

Not all amphoteric oxides react equally with bases and acids. Some have more pronounced basic properties, while others are acidic.

If zinc or chromium oxide reacts equally with acids and bases, then Fe₂O₃ oxide is dominated by basic properties.

The properties of amphoteric oxides are shown using ZnO as an example:

ZnO + 2HCl = ZnCl₂ + H₂O

ZnO + 2NaOH = Na₂ZnO₂ + H₂O

Non-salt-forming oxides form neither acids nor bases (eg N₂O, NO).

In addition, they do not give reactions characteristic of salt-forming oxides. Non-salt-forming oxides can react with acids or alkalis, but products characteristic of salt-forming oxides do not form, for example, at 150 ° C and 1.5 MPa, CO reacts with sodium hydroxide to form a salt - sodium formate:

CO + NaOH = HCOONa

Non-salt-forming oxides are not as widespread as other types of oxides and are formed mainly with the participation of divalent non-metals.

Basic Amphoteric Acids

Non-salt-forming oxides - these are oxides that do not interact with either bases or acids and therefore do not form salts. These include: N 2 O, NO, SiO, CO (CO with alkali melts forms salts of formic acid - formates). Such oxides do not have hydrates (water compounds).

Salt-forming oxides - These are oxides that, when reacted with acids or bases (or both), form salts. Such oxides as hydrates correspond to bases, acids or amphoteric hydroxides.

BASIC OXIDES

Basic oxides- these are oxides, to which bases correspond as hydrates (aqueous compounds), and when interacting with acids, they form salts. These include only metal oxides: Li 2 O, Na 2 O, K 2 O, Rb 2 O, Cs 2 O, Fr 2 O, MgO, CaO, SrO, BaO, RaO, Cu 2 O, Ag 2 O, In 2 O, PoO, Sc 2 O 3 , La 2 O 3 , TiO, HfO, CrO, MnO, FeO, CoO, NiO, etc.

Physical properties. Basic oxides under normal conditions crystalline solids predominantly with an ionic crystal lattice . They have different colors. Oxides of alkali and alkaline earth metals are soluble in water.

Chemical properties.

1. Oxides of alkali and alkaline earth metals interact with water to form alkalis:

Na 2 O + H 2 O \u003d 2NaOH;

CaO + H 2 O \u003d Ca (OH) 2.

2. Interact with acids to form salt and water:

FeO + H 2 SO 4 \u003d FeSO 4 + H 2 O;

3K 2 O + 2H 3 PO 4 \u003d 2K 3 PO 4 + 3H 2 O.

3. Interact with acid oxides, forming a salt:

MgO + SO 2 \u003d MgSO 3;

Sc 2 O 3 + 3CO 2 \u003d Sc 2 (CO 3) 3.

4. Interact with amphoteric oxides, forming a salt:

ZnO + Na 2 O = Na 2 ZnO 2 (in melt);

ZnO + CaO = CaZnO 2 (in melt).

ACID OXIDES

Acid oxides- These are oxides, which correspond to acids as hydrates, and when interacting with bases, they form salts. Acid oxides are divided into non-metal oxides and metal oxides.

Acid oxides of non-metals and their corresponding acids:

B 2 O 3 → H 3 BO 3 → HBO 3

orthoboric metaboric

SiO 2 → H 4 SiO 4 → H 2 SiO 3

orthosilicon metasilicon

CO 2 → H 2 CO 3

coal

As 2 O 5 → H 3 AsO 4 → HAsO 3

orthoarsenic metaarsenic

P 2 O 3 → H 3 PO 3 → HPO 2

orthophosphorous metaphosphorous

P 2 O 5 → H 3 PO 4 → HPO 3

orthophosphoric metaphosphoric

2H 3 PO 4 → H 4 P 2 O 7

diphosphoric (two-phosphoric, pyrophosphoric)

N 2 O 3 → HNO 2

nitrogenous

N 2 O 5 → HNO 3

NO 2 nitric (NO 2 - mixed oxide, anhydride of two acids)

nitrogenous

TeO 2 → H 2 TeO 3

telluric

TeO 3 → H 6 TeO 6 → H 2 TeO 4

orthotelluric metatelluric

SeO 2 → H 2 SeO 3

selenium

SeO 3 → H 2 SeO 4

selenic

SO 2 → H 2 SO 3

sulphurous

SO 3 → H 2 SO 4

Cl 2 O → HClO

hypochlorous

Cl 2 O 3 → HClO 2

chloride

Cl 2 O 5 → HClO 3

chlorine

Cl 2 O 7 → HClO 4

For all halogens (except fluorine), the forms of oxides and acids are similar to those of chlorine. Fluorine is more electronegative than oxygen, so it forms fluorides with oxygen. O 2 F 2 , OF 2 where the oxygen atoms are positively polarized.

Acidic metal oxides and their corresponding acids:

Au 2 O 3 → H 3 AuO 3 → HAuO 2

orthogold metagold

V 2 O 5 → H 3 VO 4 → HVO 3

orthovanadium metavanadium

CrO 3 → H 2 CrO 4

chrome

2H 2 CrO 4 → H 2 Cr 2 O 7

dichrome

MnO 3 → H 2 MnO 4

manganese

Mn 2 O 7 → HMnO 4

manganese

physical properties. Under normal conditions, acid oxides have a variety of properties: they can be gases (CO 2, SO 2, Cl 2 O), crystalline substances with an atomic crystal lattice (SiO 2, CrO 3) or with a molecular crystal lattice
(P 2 O 3 , P 2 O 5). They have different colors, melting and boiling points vary over a wide range. Most acidic oxides are highly soluble in water. Hardly soluble is silicon oxide (IV) SiO 2 , which is an integral part of quartz sand.

Chemical properties.

1. Interact with water to form the corresponding acids:

SO 2 + H 2 O \u003d H 2 SO 3;

P 2 O 5 + H 2 O \u003d 2HPO 3;

P 2 O 5 + 3H 2 O \u003d 2H 3 PO 4;

2H 3 PO 4 \u003d H 4 P 2 O 7 + H 2 O.

2. Interact with alkalis, forming salt and water:

SiO 2 + 2NaOH \u003d Na 2 SiO 3 + H 2 O;

P 2 O 5 + 3Ca (OH) 2 \u003d Ca 3 (PO 4) 2 + 3H 2 O.

3. Interact with basic oxides, forming a salt:

CrO 3 + CaO \u003d CaCrO 4;

CO 2 + Na 2 O \u003d Na 2 CO 3.

4. Interact with amphoteric oxides, forming a salt:

CO 2 + ZnO = ZnCO 3;

3SO 3 + Al 2 O 3 \u003d Al 2 (SO 4) 3.

5. Interact with salts if gaseous oxide is released as a result of the reaction:

SiO 2 + Na 2 CO 3 \u003d Na 2 SiO 3 + CO 2;

SO 3 + Na 2 SO 3 \u003d Na 2 SO 4 + SO 2.

AMPHOTERIC OXIDES

Amphoteric oxides are oxides, which correspond to amphoteric hydroxides as hydrates. They form salts when they react with both acids and bases. These include:

VeO, Al 2 O 3 , GeO, GeO 2 , SnO, SnO 2 , PbO, PbO 2 , Sb 2 O 3 , Sb 2 O 5 , Bi 2 O 3 , Bi 2 O 5 , ZnO, V 2 O 3 , Cr 2 O 3 , MnO 2 , Fe 2 O 3 , etc.

Physical properties. All amphoteric oxides under normal conditions solids, have different colors, are insoluble in water.

Chemical properties. Amphotericity is proved by interaction with acids and acid oxides (basic properties), with bases and basic oxides (acid properties).

1. Interact with acids, showing the main properties:

Al 2 O 3 + 3H 2 SO 4 \u003d Al 2 (SO 4) 3 + 3H 2 O

aluminum sulfate or

aluminum tetraoxosulfate (VI).

2. Interact with acid oxides, showing the main properties:

Al 2 O 3 + 3CO 2 \u003d Al 2 (CO 3) 3

aluminum carbonate or

aluminum trioxocarbonate (IV).

3. Interact with melts and alkali solutions, showing acidic properties:

Al 2 O 3 + 6NaOH \u003d 2Na 3 AlO 3 + 3H 2 O (in melt)

sodium orthoaluminate or

sodium trioxoaluminate;

Al 2 O 3 + 2NaOH = 2NaAlO 2 + H 2 O (in melt)

sodium metaaluminate or

sodium dioxoaluminate;

Al 2 O 3 + 6NaOH + 3H 2 O = 2Na 3 (in solution)

sodium hexahydroxoaluminate;

Al 2 O 3 + 2NaOH + 3H 2 O = 2Na (in solution)

sodium tetrahydroxoaluminate.

4. Interact with basic oxides, showing acidic properties:

Al 2 O 3 + 3CaO \u003d Ca 3 (AlO 3) 2

calcium orthoaluminate or calcium trioxoaluminate;

Al 2 O 3 + CaO \u003d Ca (AlO 2) 2

calcium metaaluminate or

calcium dioxoaluminate.

OBTAINING OXIDES

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

2Mg + O 2 \u003d 2MgO;

S + O 2 \u003d SO 2.

2. Decomposition of some oxygen-containing acids (hydroxy acids):

2H 3 BO 3 = B 2 O 3 + 3H 2 O;

H 2 SO 3 \u003d SO 2 + H 2 O.

3. Decomposition of insoluble bases.

Oxides - complex substances, consisting of two elements, one of which is oxygen. Oxides can be salt-forming and non-salt-forming: one type of salt-forming oxides are basic oxides. How do they differ from other species, and what are their chemical properties?

Salt-forming oxides are divided into basic, acidic and amphoteric oxides. If basic oxides correspond to bases, then acidic oxides correspond to acids, and amphoteric oxides correspond to amphoteric formations. Amphoteric oxides are compounds that, depending on the conditions, can exhibit either basic or acidic properties.

Rice. 1. Classification of oxides.

The physical properties of oxides are very diverse. They can be both gases (CO 2) and solid (Fe 2 O 3) or liquid substances (H 2 O).

However, most of the basic oxides are solids of various colors.

oxides in which the elements exhibit their highest activity are called higher oxides. Ascending order acid properties higher oxides of the corresponding elements in periods from left to right is explained by a gradual increase in the positive charge of the ions of these elements.

Chemical properties of basic oxides

Basic oxides are oxides that correspond to bases. For example, the basic oxides K 2 O, CaO correspond to the bases KOH, Ca (OH) 2.

Rice. 2. Basic oxides and their corresponding bases.

Basic oxides are formed typical metals, as well as metals of variable valence in the lowest oxidation state (for example, CaO, FeO), react with acids and acid oxides, forming salts:

CaO (basic oxide) + CO 2 (acid oxide) \u003d CaCO 3 (salt)

FeO (basic oxide) + H 2 SO 4 (acid) \u003d FeSO 4 (salt) + 2H 2 O (water)

Basic oxides also interact with amphoteric oxides, resulting in the formation of a salt, for example:

Only oxides of alkali and alkaline earth metals react with water:

BaO (basic oxide) + H 2 O (water) \u003d Ba (OH) 2 (alkaline earth metal base)

Many basic oxides tend to be reduced to substances consisting of atoms of one chemical element:

3CuO + 2NH 3 \u003d 3Cu + 3H 2 O + N 2

When heated, only oxides of mercury and precious metals decompose:

Rice. 3. Mercury oxide.

List of main oxides:

Oxide name	Chemical formula	Properties
calcium oxide	CaO	quicklime, white crystalline substance
magnesium oxide	MgO	white matter, insoluble in water
barium oxide	BaO	colorless crystals with a cubic lattice
Copper oxide II	CuO	black substance practically insoluble in water
	HgO	red or yellow-orange solid
potassium oxide	K2O	colorless or pale yellow substance
sodium oxide	Na2O	a substance consisting of colorless crystals
lithium oxide	Li2O	a substance consisting of colorless crystals that have a cubic lattice structure

Today we begin our acquaintance with the most important classes inorganic compounds. Inorganic substances are divided by composition, as you already know, into simple and complex.

OXIDE	ACID	BASE	SALT
E x O y	HnA A - acid residue	Me(OH)b OH - hydroxyl group	Me n A b

Complex inorganic substances are divided into four classes: oxides, acids, bases, salts. We start with the oxide class.

OXIDES

oxides - these are complex substances consisting of two chemical elements, one of which is oxygen, with a valence equal to 2. Only one chemical element - fluorine, combining with oxygen, forms not an oxide, but oxygen fluoride OF 2.
They are called simply - "oxide + element name" (see table). If the valency of a chemical element is variable, then it is indicated by a Roman numeral enclosed in parentheses after the name of the chemical element.

Formula	Name	Formula	Name
	carbon monoxide (II)	Fe2O3	iron(III) oxide
	nitric oxide (II)	CrO3	chromium(VI) oxide
Al2O3	aluminium oxide		zinc oxide
N 2 O 5	nitric oxide (V)	Mn2O7	manganese(VII) oxide

Classification of oxides

All oxides can be divided into two groups: salt-forming (basic, acidic, amphoteric) and non-salt-forming or indifferent.

metal oxides Me x O y			Non-metal oxides neMe x O y
Main	Acidic	Amphoteric	Acidic	Indifferent
I, II Me	V-VII Me	ZnO, BeO, Al 2 O 3, Fe 2 O 3 , Cr 2 O 3	> II neMe	I, II neMe CO, NO, N 2 O

1). Basic oxides are oxides that correspond to bases. The main oxides are oxides metals 1 and 2 groups, as well as metals side subgroups with valence I And II (except ZnO - zinc oxide and BeO – beryllium oxide):

2). Acid oxides are oxides to which acids correspond. Acid oxides are non-metal oxides (except for non-salt-forming - indifferent), as well as metal oxides side subgroups with valence from V before VII (For example, CrO 3 is chromium (VI) oxide, Mn 2 O 7 is manganese (VII) oxide):

3). Amphoteric oxides are oxides, which correspond to bases and acids. These include metal oxides main and secondary subgroups with valence III , sometimes IV , as well as zinc and beryllium (For example, BeO, ZnO, Al 2 O 3, Cr 2 O 3).

4). Non-salt-forming oxides are oxides that are indifferent to acids and bases. These include non-metal oxides with valence I And II (For example, N 2 O, NO, CO).

Conclusion: the nature of the properties of oxides primarily depends on the valency of the element.

For example, chromium oxides:

CrO(II- main);

Cr 2 O 3 (III- amphoteric);

CrO 3 (VII- acid).

Classification of oxides

(by solubility in water)

Acid oxides	Basic oxides	Amphoteric oxides
Soluble in water. Exception - SiO 2 (not soluble in water)	Only oxides of alkali and alkaline earth metals dissolve in water. (these are metals I "A" and II "A" groups, exception Be , Mg )	They do not interact with water. Insoluble in water

Complete the tasks:

1. Write separately chemical formulas salt-forming acidic and basic oxides.

NaOH, AlCl 3 , K 2 O, H 2 SO 4 , SO 3 , P 2 O 5 , HNO 3 , CaO, CO.

2. Substances are given : CaO, NaOH, CO 2 , H 2 SO 3 , CaCl 2 , FeCl 3 , Zn(OH) 2 , N 2 O 5 , Al 2 O 3 , Ca(OH) 2 , CO 2 , N 2 O, FeO, SO 3 , Na 2 SO 4 , ZnO, CaCO 3 , Mn 2 O 7 , CuO, KOH, CO, Fe(OH) 3

Write down the oxides and classify them.

Obtaining oxides

Simulator "Interaction of oxygen with simple substances"

1. Combustion of substances (Oxidation by oxygen)	a) simple substances Training apparatus	2Mg + O 2 \u003d 2MgO
	b) complex substances	2H 2 S + 3O 2 \u003d 2H 2 O + 2SO 2
2. Decomposition of complex substances (use table of acids, see appendices)	a) salt SALTt= BASIC OXIDE + ACID OXIDE	CaCO 3 \u003d CaO + CO 2
	b) Insoluble bases Me(OH)bt= Me x O y+ H 2 O	Cu (OH) 2 t \u003d CuO + H 2 O
	c) oxygen-containing acids HnA=ACID OXIDE + H 2 O	H 2 SO 3 \u003d H 2 O + SO 2

Physical properties of oxides

At room temperature, most oxides are solids (CaO, Fe 2 O 3, etc.), some are liquids (H 2 O, Cl 2 O 7, etc.) and gases (NO, SO 2, etc.).

Chemical properties of oxides

CHEMICAL PROPERTIES OF BASIC OXIDES 1. Basic oxide + Acid oxide \u003d Salt (r. compounds) CaO + SO 2 \u003d CaSO 3 2. Basic oxide + Acid \u003d Salt + H 2 O (r. exchange) 3 K 2 O + 2 H 3 PO 4 = 2 K 3 PO 4 + 3 H 2 O 3. Basic oxide + Water \u003d Alkali (r. compounds) Na 2 O + H 2 O \u003d 2 NaOH

CHEMICAL PROPERTIES OF ACID OXIDES 1. Acid oxide + Water \u003d Acid (p. Compounds) With O 2 + H 2 O \u003d H 2 CO 3, SiO 2 - does not react 2. Acid oxide + Base \u003d Salt + H 2 O (r. exchange) P 2 O 5 + 6 KOH \u003d 2 K 3 PO 4 + 3 H 2 O 3. Basic oxide + Acid oxide \u003d Salt (p. Compound) CaO + SO 2 \u003d CaSO 3 4. Less volatiles displace more volatiles from their salts CaCO 3 + SiO 2 \u003d CaSiO 3 + CO 2

CHEMICAL PROPERTIES OF AMPHOTERIC OXIDES They interact with both acids and alkalis. ZnO + 2 HCl = ZnCl 2 + H 2 O ZnO + 2 NaOH + H 2 O \u003d Na 2 [Zn (OH) 4] (in solution) ZnO + 2 NaOH = Na 2 ZnO 2 + H 2 O (when fused)

Application of oxides

Some oxides do not dissolve in water, but many react with water to combine:

SO 3 + H 2 O \u003d H 2 SO 4

CaO + H 2 O = Ca( Oh) 2

The result is often very desirable and useful compounds. For example, H 2 SO 4 is sulfuric acid, Ca (OH) 2 is slaked lime, etc.

If oxides are insoluble in water, then people skillfully use this property as well. For example, zinc oxide ZnO is a white substance, therefore it is used to prepare white oil paint (zinc white). Since ZnO is practically insoluble in water, any surface can be painted with zinc white, including those that are exposed to atmospheric precipitation. Insolubility and non-toxicity make it possible to use this oxide in the manufacture of cosmetic creams and powders. Pharmacists make it an astringent and drying powder for external use.

Titanium oxide (IV) - TiO 2 has the same valuable properties. He also has a handsome White color and is used for the manufacture of titanium white. TiO 2 is insoluble not only in water, but also in acids; therefore, coatings made of this oxide are particularly stable. This oxide is added to plastic to give it a white color. It is part of the enamels for metal and ceramic utensils.

Chromium oxide (III) - Cr 2 O 3 - very strong crystals of dark green color, insoluble in water. Cr 2 O 3 is used as a pigment (paint) in the manufacture of decorative green glass and ceramics. The well-known GOI paste (short for the name “State Optical Institute”) is used for grinding and polishing optics, metal products in jewelry.

Due to the insolubility and strength of chromium (III) oxide, it is also used in printing inks (for example, for coloring banknotes). In general, oxides of many metals are used as pigments for a wide variety of paints, although this is by no means their only application.

Tasks for fixing

1. Write down separately the chemical formulas of salt-forming acidic and basic oxides.

NaOH, AlCl 3 , K 2 O, H 2 SO 4 , SO 3 , P 2 O 5 , HNO 3 , CaO, CO.

2. Substances are given : CaO, NaOH, CO 2 , H 2 SO 3 , CaCl 2 , FeCl 3 , Zn(OH) 2 , N 2 O 5 , Al 2 O 3 , Ca(OH) 2 , CO 2 , N 2 O, FeO, SO 3 , Na 2 SO 4 , ZnO, CaCO 3 , Mn 2 O 7 , CuO, KOH, CO, Fe(OH) 3

Select from the list: basic oxides, acidic oxides, indifferent oxides, amphoteric oxides and name them.

3. Finish UCR, indicate the type of reaction, name the reaction products

Na 2 O + H 2 O =

N 2 O 5 + H 2 O =

CaO + HNO 3 =

NaOH + P 2 O 5 \u003d

K 2 O + CO 2 \u003d

Cu (OH) 2 \u003d? +?

4. Carry out the transformations according to the scheme:

1) K → K 2 O → KOH → K 2 SO 4

2) S → SO 2 → H 2 SO 3 → Na 2 SO 3

3) P → P 2 O 5 → H 3 PO 4 → K 3 PO 4

oxides - complex substances consisting of two elements, one of which is an oxygen atom in the oxidation state -2.
According to the ability to form salts, oxides are divided into salt-forming And non-salt-forming(CO, SiO, NO, N 2 O). Salt-forming oxides, in turn, are classified into basic, acidic and amphoteric.
Basic oxides are called oxides, which correspond to bases, acidic - oxides, to which acids correspond. Amphoteric oxides include oxides that exhibit the chemical properties of both basic and acidic oxides.
Basic oxides form only metal elements: alkaline (Li 2 O, Na 2 O, K 2 O, Cs 2 O, Rb 2 O), alkaline earth (CaO, SrO, BaO, RaO) and magnesium (MgO), as well as metals d-families in the oxidation state +1, +2, less often +3 (Cu 2 O, CuO, Ag 2 O, CrO, FeO, MnO, CoO, NiO).

Acid oxides form both non-metal elements (CO 2, SO 2, NO 2, P 2 O 5, Cl 2 O 7) and metal elements, the oxidation state of the metal atom must be +5 and higher (V 2 O 5, CrO 3 , Mn 2 O 7 , MnO 3). Amphoteric oxides form only metal elements (ZnO, AI 2 O 3, Fe 2 O 3, BeO, Cr 2 O 3, PbO, SnO, MnO 2).

Under normal conditions, oxides can be found in three states of aggregation: all basic and amphoteric oxides are solids, acid oxides can be liquid (SO 3, Cl 2 O7, Mn 2 O7), gaseous (CO 2, SO 2, NO 2) and solid (P 2 O 5 , SiO 2). Some have an odor (NO 2 , SO 2), but most oxides are odorless. Some oxides are colored: brown gas NO 2, cherry red CrO 3, black CuO and Ag 2 O, red Cu 2 O and HgO, brown Fe 2 O 3, white SiO 2, Al 2 O 3 and ZnO, others are colorless (H 2 O, CO 2 , SO2).

Most oxides are stable when heated; oxides of mercury and silver easily decompose when heated. Basic and amphoteric oxides have, they are characterized by crystal cell ion type. Most acidic oxides of matter (one of the few exceptions is silicon (IV) oxide, which has an atomic crystal lattice).

Al 2 O 3 +6KOH+3H 2 O=2K 3 - potassium hexahydroxoaluminate;
ZnO+2NaOH+H 2 O=Na 2 - sodium tetrahydroxozincate;