Author: Chemical Encyclopedia N.S. Zefirov

CHLORINE OXIDES. All CHLORINE OXIDES o. have a pungent odor, are thermally and photochemically unstable, prone to explosive decomposition, have a positive Monoxide [Cl(I) oxide, dichloroxide, hemioxide] Cl 2 O is a yellow-orange gas with a faint greenish tint, in the liquid state it is red-brown; Cl - O bond length 0.1700 nm, angle OClO 111°, 2.60 x 10 -30 Cl x m (table); equation for the temperature dependence of steam pressure logp (mm Hg) = 7.87 - 1373/T (173-288 K); soluble in water to form HNS, solubility (g in 100 g of H 2 O at 0 °C): 33.6 (2.66 kPa), 52.4 (6.65 kPa). At 60-100 °C, the thermodynamic decomposition of Cl 2 O is completed in 12-24 hours; above 110 °C, an explosion occurs after a few minutes; lighting accelerates the decomposition and increases the likelihood of an explosion. With chlorides it forms oxychlorides, for example, with T1Cl 4, TaCl 5 and AsCl 3 it gives T1OCl 2, TaOCl 3 and AsO 2 Cl, respectively. With NO 2 it forms a mixture of NO 2 Cl and NO 3 Cl, with N 2 O 5 - pure NO 3 Cl. Fluorination of Cl 2 O with AgF 2 can produce ClOF 3, and by reaction with AsF 5 or SbF 5 - chloryl salts ClO + 2 MF - 6. ClO 2 and Cl 2 O 6 react similarly with MF 5 (where M is As and Sb). With sat. organic compounds Cl 2 O behaves as a chlorinating agent, similar to chlorine. Cl 2 O is prepared by passing Cl 2 diluted with N 2 over HgO or by reacting Cl 2 with wet Na 2 CO 3 .

PROPERTIES OF CHLORINE OXIDES

Index
boiling point, °C
Density, g/cm 3				2.023 (3.5 °C)	1.805** (25 °C)
J/(mol x K)
KJ/mol
KJ/mol
J/(mol x K)

*Calculated. **2.38 g/cm 3 at -160 °C.

Dioxide ClO 2 is a yellow gas, in the liquid state it is bright red, in the solid state it is reddish-yellow; C - O bond length 0.1475 nm, OClO angle 117 °C; equation for the temperature dependence of steam pressure logp (mm Hg) = 7.7427 - 1275.1/T (226-312 K); solubility in water 26.1 g/l (25 °C, 20.68 kPa), soluble in CCl 4, HClO 4, CH 3 COOH. In the individual state it is explosive, at 30-50 ° C the decomposition occurs at a measurable rate, above 50 ° C it explodes after an induction period. In an alkaline environment, ClO 2 is disproportionate to and, in the presence. H 2 O 2 is formed and O 2 is released. It is reduced by iodides, arsenides, PbO, H 2 SO 3, amines to chlorite ion. CNO 2 and N 2 O 5 form NO 3 Cl, with NOCl -NO 2 Cl. Fluorinated with AgF 2, BrF 3 or diluted F 2 to ClO 2 F. ClO 2 is obtained by the action of reducing agents (SO 2, NO 2, methanol, organic peroxides) on an acidified solution of alkali metal chlorate, by heating a mixture of chlorate with wet oxalic acid, the action Cl 2 for chlorites. Unlike the rest, CHLORINE OXIDES o. ClO 2 - industrial product. production, it is used instead of Cl 2 as an environmentally safer product for bleaching wood pulp, cellulose, synthetics. fibers, for the preparation of drinking and technol. water, wastewater disinfection. Irritates mucous membranes, causes coughing, vomiting, etc.; MPC in the air of the working area 0.1 mg/m 3, LD 50 140 mg/kg (rats, intragastric).
Chlorine perchlorate (cichlorotetroxide) Cl 2 O 4, or СlOClО 3 - light yellow liquid, crystalline. state is almost colorless (see Perchlorates).
Trioxide (dichlorohexaoxide) Cl 2 O 6 is a bright red liquid, in the solid state it is orange, the color weakens when cooled. In gases and liquids, molecules have the structure O 2 Cl - O - ClO 3, in crystals they are crystals of the monoclinic system (space group, z = 4); steam pressure 39.9 Pa (0 °C), 133 Pa (19 °C). Slowly decomposes already at 0-10 ° C into ClO 2 and O 2, above 20 ° C Cl 2 appears in the decomposition products; reacts with water with a flash, the products of hydrolysis are HClO 3 and HClO 4. With chlorides, bromides, nitrates it forms perchlorates, for example with NOCl it gives NOClO 4, with N 2 O 5 - NO 2 ClO 4, with AlCl 3 - ClO 2, with FeCl 3 - ClO 2. When heated in a vacuum, such complexes split off Cl 2 O 6 and turn into unsolvated perchlorates Al(ClO 4) 3, Fe(ClO 4) 3. Cl 2 O 6 is obtained by the reaction of ozone with ClO 2 or the action of F 2 on metal chlorates. Used for the synthesis of anhydrous perchlorates in laboratory conditions.
Cl(VII) oxide (chloric anhydride, dichloroheptaoxide) Cl 2 O 7 - colorless. mobile liquid, sensitive to impact and friction. The molecule has the structure O 3 Cl - O - ClO 3, the Cl - O bond length is 0.1709 nm, in ClO 3 groups - 0.1405 nm, ClOCl angle 118.6°, OClO 115.2°, 2.40 x 10 -30 Kl x m; monoclinic crystals (space group C 2/c); equation for the temperature dependence of steam pressure lgp (mm Hg) = 7.796-1770/T. Unlimitedly soluble in CCl 4, highly soluble in HClO 4, POCl 3, etc. It does not mix with water, it reacts at the phase boundary to form HClO 4, the reaction is highly exothermic -211 kJ/mol); heating the Cl 2 O 7 layer can lead to an explosion. The decomposition of Cl 2 O 7 in gas into chlorine and oxygen occurs at a measurable rate at 100-120 ° C, but at a pressure of Cl 2 O 7 above 13.3 kPa it becomes explosive. Liquid Cl 2 O 7 is stable up to 60-70 ° C, an admixture of lower CHLORINE OXIDES o. accelerates its decay. Liquid Cl 2 O 7 is characterized by reactions with the formation of covalent compounds with the group - ClO 3. With NH 3 in CCl 4 it forms NH 4 HNClO 3 and NH 4 ClO 4, with alkylamines - RHNClO 3 and R 2 NClO 3, respectively, with SbF 5 - SbOF 3 and FClO 3, with N 2 O 5 in CCl 4 NO 2 ClO 4 . Using Cl 2 About 7, you can synthesize organic perchlorates from alcohols. Cl 2 O 7 is obtained by the action of P 2 O 5 or oleum on perchloric acid or by electrolysis of an HClO 4 solution on Pt electrodes below 0 ° C (Cl 2 O 7 accumulates in the anode space). Pure Cl 2 O 7 can also be obtained by heating some perchlorates in a vacuum, for example Nb(ClO 4) 5, MoO 2 (ClO 4) 2.
A number of chlorine-oxygen free radicals are known, obtained in various low-temperature matrices and studied mainly by the EPR method - ClO 3, ClOO, ClClO, as well as the low-stable sesquioxide Cl 2 O 3, which decomposes at -50 - 0 ° C and probably has the structure of chlorine chlorate СlOClO2. Thermally stable radical ClO (Cl - O bond length 0.1569 nm, 4.133 C x m, 101.6 kJ/mol) is an intermediate product of the oxidation of hydrocarbons with perchloric acid and CHLORINE OXIDES o., the decomposition of all CHLORINE OXIDES o. and other chlorine-oxygen compounds, as well as the reaction of ozone with atomic chlorine in the stratosphere.

Literature: Nikitin I.V., Chemistry of oxygen compounds of halogens, M., 1986.

V.Ya.Rosolovsky.

Chemical encyclopedia. Volume 5 >>

August 19, 2012

Oxides or oxides are compounds of various elements with oxygen. Almost all elements form such compounds. Chlorine, like other halogens, is characterized in such compounds by a positive oxidation state. All chlorine oxides are extremely unstable substances, which is typical for the oxides of all halogens. There are four known substances whose molecules contain chlorine and oxygen.

1. A gaseous compound from yellow to reddish color with a characteristic odor (reminiscent of the smell of Cl2 gas) is chlorine oxide (I). Chemical formula Cl2O. Melting point minus 116 °C, boiling point plus 2 °C. Under normal conditions, its density is 3.22 kg/m³.
2. A yellow or yellow-orange gas with a characteristic odor is chlorine oxide (IV). Chemical formula ClO2. Melting point minus 59 °C, boiling point plus 11 °C.
3. The red-brown liquid is chlorine oxide (VI). Chemical formula Cl2O6. Melting point plus 3.5 °C, boiling point plus 203 °C.
4. Colorless oily liquid - chlorine oxide (VII). Chemical formula Cl2O7. Melting point minus 91.5 °C, boiling point plus 80 °C.

Chlorine oxide with oxidation state +1 is the anhydride of weak monohydric hypochlorous acid (HClO). It is obtained using the Pelouse method by reacting mercury oxide with chlorine gas according to one of the reaction equations: 2Cl2 + 2HgO → Cl2O + Hg2OCl2 or 2Cl2 + HgO → Cl2O + HgCl2. The conditions for these reactions are different. Chlorine oxide (I) condenses at a temperature of minus 60 oC, because at higher temperatures it decomposes, exploding, and in concentrated form is explosive. An aqueous solution of Cl2O is obtained by chlorinating alkaline earth or alkali metal carbonates in water. The oxide dissolves well in water, and hypochlorous acid is formed: Cl2O + H2O ↔ 2HClO. In addition, it is also soluble in carbon tetrachloride.

Chlorine oxide with an oxidation state of +4 is otherwise called dioxide. This substance is soluble in water, sulfuric and acetic acids, acetonitrile, carbon tetrachloride, as well as in other organic solvents, with increasing polarity its solubility increases. In laboratory conditions, it is obtained by reacting potassium chlorate with oxalic acid: 2KClO3 + H2C2O4 → K2CO3 + 2ClO2 + CO2 + H2O. Since chlorine oxide (IV) is an explosive substance, it cannot be stored in solution. For these purposes, silica gel is used, on the surface of which ClO2 can be stored in adsorbed form for a long time, while at the same time it is possible to get rid of chlorine contaminants, since it is not absorbed by silica gel. Under industrial conditions, ClO2 is obtained by reduction with sulfur dioxide, in the presence of sulfuric acid, sodium chlorate: 2NaClO3 + SO2 + H2SO4 → 2NaHSO4 + 2ClO2. It is used as a bleaching agent, for example, paper or cellulose, etc., as well as for sterilization and disinfection of various materials.

Chlorine oxide with an oxidation state of +6, upon melting, decomposes according to the reaction equation: Cl2O6 → 2ClO3. Chlorine oxide (VI) is obtained by oxidizing dioxide with ozone: 2O3 + 2ClO2 → 2O2 + Cl2O6. This oxide is capable of interacting with alkali solutions and water. In this case, disproportionation reactions occur. For example, when reacting with potassium hydroxide: 2KOH + Cl2O6 → KClO3 + KClO4 + H2O, the result is potassium chlorate and perchlorate.

Higher chlorine oxide is also called chloric anhydride or dichloroheptaoxide and is a strong oxidizing agent. It can explode on impact or when heated. However, this substance is more stable than oxides with oxidation states +1 and +4. Its decomposition to chlorine and oxygen accelerates due to the presence of lower oxides and with an increase in temperature from 60 to 70 oC. Chlorine oxide (VII) is able to slowly dissolve in cold water; as a result of the reaction, perchloric acid is formed: H2O + Cl2O7 → 2HClO4. Dichloroheptaoxide is obtained by carefully heating perchloric acid with phosphoric anhydride: P4O10 + 2HClO4 → Cl2O7 + H2P4O11. Cl2O7 can also be obtained by using oleum instead of phosphoric anhydride.

The branch of inorganic chemistry, which studies halogen oxides, including chlorine oxides, has begun to develop actively in recent years, since these compounds are energy-intensive. They are capable of releasing energy instantly in the combustion chambers of jet engines, and in chemical current sources the rate of its release can be regulated. Another reason for interest is the possibility of synthesizing new groups of inorganic compounds, for example, chlorine oxide (VII) is the ancestor of perchlorates.

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Current

Chlorine forms a number of oxides with oxygen, the total number of which is as many as five types. All of them can be described by the general formula ClxOy. In them, the valence of chlorine varies from 1 to 7.

The valency of different chlorine oxides is different: Cl2O - 1, Cl2O3 - 3, ClO2 - 4, Cl2O6 - 6, Cl2O7 - 7.

Chlorine(I) oxide is used to produce hypochlorites, which are strong bleaching and disinfecting agents.
Chlorine(II) oxide is actively used for bleaching flour, cellulose, paper and other things, as well as for sterilization and disinfection.
Chlorine(VI) oxide and chlorine(VII) oxide are used for the synthesis of organic compounds.

Obtaining Cl2O

This oxide is produced in large-scale production in two ways.
1. According to the Pelouz method. A reaction is carried out between chlorine gas and mercury oxide. Depending on the conditions, a different mercury compound may be formed, but the target product remains. After this, the chlorine oxide gas is liquefied at a temperature of - Celsius.

Reaction equations describing the Pelouse method:
2HgO + Cl2 = Hg2OCl2 + Cl2O
HgO + 2Cl2 = HgCl2 + Cl2O

2. The interaction of chlorine with the reaction:
2Cl2 + 2Na2CO3 + H2O = 2NaHCO3 + Cl2O + 2NaCl
Sodium carbonate may be replaced by other alkali or alkaline earth metal carbonates.

Obtaining ClO2

The only industrial method for producing chlorine dioxide is based on the interaction of sodium chlorate and sulfur dioxide in an acidic environment. The result of this interaction is the reaction:
2NaClO3 + SO2 + H2SO4 = 2NaHSO4 + ClO2

Obtaining Cl2O6

In industry, Cl2O6 is obtained by reacting chlorine dioxide with ozone:
2ClO2 + 2O3 = 2O2 + Cl2O6

Preparation of Cl2O7

1. Gently heating perchloric acid with phosphoric anhydride separates an oily liquid, which is chlorine(VII) oxide. The whole process is described by the reaction:
2HClO4 + P4O10 = H2P4O11 + Cl2O7

2. The second method of obtaining this oxide is associated with electricity. If you carry out a solution of perchloric acid, then Cl2O7 can be found in the anode space.

3. Heating transition metal perchlorates in vacuum leads to the formation of chlorine oxide (VII). The most commonly heated materials are perchlorate or molybdenum.

Physical properties of oxides

Cl2O: under standard conditions a brownish-yellow gas with a chlorine odor, and at temperatures below +2 degrees Celsius a golden-red liquid. Explosive in high concentrations.

ClO2: under standard conditions - a gas with a characteristic odor of red-yellow color, at temperatures below +10 degrees Celsius - a red-brown liquid. Explodes in light, in the presence of reducing agents and when heated.

Cl2O6: an unstable gas that begins to decompose at temperatures between 0 and +10 degrees Celsius to form chlorine dioxide, at 20 degrees Celsius chlorine is formed. Due to the formation of chlorine dioxide, it is explosive.

Cl2O7: A colorless oily liquid that explodes when heated above 120 degrees Celsius. May detonate on impact.

Chlorine(VII) oxide
Dichlorine-heptoxide-3D-balls.png
Are common
Systematic Name	Chlorine(VII) oxide
Chem. formula	Cl2O7
Physical properties
State	liquid
Molar mass	182.901 g/mol
Thermal properties
T. float.	−91.5 °C
T. kip.	82°C
T. dec.	120 °C
Enthalpy of formation	251.0 kJ/mol
Classification
Reg. CAS number
Data are based on standard conditions (25 °C, 100 kPa) unless otherwise stated.

Chlorine(VII) oxide(dichloroheptaoxide) Cl 2 O 7 , ( chloric anhydride) - acidic oxide. The highest oxide of chlorine, in which it exhibits an oxidation state of +7.

The Cl 2 O 7 molecule has the structure O 3 Cl-O-ClO 3 (dCl-O = 0.1709 nm, in ClO 3 groups - 0.1405 nm, angle ClOCl = 118.6°, ОClO 115.2°) c spatial symmetry C 2, the molecule is polar (μ = 2.40·10 −30 C m).

Properties

Chloric anhydride is a colorless oily liquid. Cl 2 O 7 explodes when heated above 120 °C and on impact, but it is more stable than chlorine oxide and dioxide. Liquid Cl 2 O 7 is stable up to 60-70 °C, but the admixture of lower chlorine oxides significantly accelerates its decomposition:

$\backslash mathsf(2Cl\_2O\_7\; \backslash rightarrow\; 2Cl\_2\; +\; 7O\_2)$ΔH = 135 kJ/mol

Dissolves slowly in cold water, forming perchloric acid:

$\backslash mathsf(Cl\_2O\_7\; +\; H\_2O\; \backslash rightarrow\; 2HClO\_4)$

Chloric anhydride is a strong oxidizing agent.

Receipt

Cl 2 O 7 is obtained by carefully heating perchloric acid with phosphoric anhydride or oleum:

$\backslash mathsf(2HClO\_4\; +\; P\_4O\_(10)\; \backslash rightarrow\; Cl\_2O\_7\; +\; H\_2P\_4O\_(11))$

Chlorine(VII) oxide is also obtained by electrolysis of HClO 4 solution on platinum electrodes below 0 °C (Cl 2 O 7 accumulates in the anode space). Pure Cl 2 O 7 can also be synthesized by heating in vacuum some perchlorates, for example, Nb(ClO 4) 5 or MoO 2 (ClO 4) 2.

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Literature

• Remi G. “Course in Inorganic Chemistry” M.: Foreign Literature, 1963

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Excerpt characterizing Chlorine(VII) oxide

– Courte et energique! [Short and energetic!] - said Napoleon when he read the written proclamation immediately without amendments. The order was:
“Warriors! This is the battle you have longed for. Victory depends on you. It is necessary for us; she will provide us with everything we need: comfortable apartments and a quick return to our homeland. Act as you acted at Austerlitz, Friedland, Vitebsk and Smolensk. May later posterity proudly remember your exploits to this day. Let it be said about each of you: he was in the great battle near Moscow!”
– De la Moscow! [Near Moscow!] - Napoleon repeated, and, inviting Mr. Bosset, who loved to travel, to join him in his walk, he left the tent to the saddled horses.
“Votre Majeste a trop de bonte, [You are too kind, Your Majesty," Bosse said when asked to accompany the emperor: he was sleepy and did not know how and was afraid to ride a horse.
But Napoleon nodded to the traveler, and Bosse had to go. When Napoleon left the tent, the screams of the guards in front of the portrait of his son intensified even more. Napoleon frowned.
“Take it off,” he said, pointing to the portrait with a graceful, majestic gesture. “It’s too early for him to see the battlefield.”
Bosse, closing his eyes and bowing his head, took a deep breath, with this gesture showing how he knew how to appreciate and understand the words of the emperor.

Napoleon spent the entire day of August 25, as his historians say, on horseback, inspecting the area, discussing the plans presented to him by his marshals, and personally giving orders to his generals.
The original line of Russian troops along Kolocha was broken, and part of this line, namely the Russian left flank, was driven back as a result of the capture of the Shevardinsky redoubt on the 24th. This part of the line was not fortified, no longer protected by the river, and in front of it there was only a more open and level place. It was obvious to every military and non-military person that the French were supposed to attack this part of the line. It seemed that this did not require many considerations, there was no need for such care and troubles of the emperor and his marshals, and there was no need at all for that special highest ability called genius, which they so like to attribute to Napoleon; but the historians who subsequently described this event, and the people then surrounding Napoleon, and he himself, thought differently.

Properties of oxides

Oxides- these are complex chemical substances, which are chemical compounds of simple elements with oxygen. They are salt-forming And non-salt forming. In this case, there are 3 types of salt-forming agents: main(from the word "foundation"), acidic And amphoteric. An example of oxides that do not form salts are: NO (nitric oxide) - is a colorless, odorless gas. It is formed during a thunderstorm in the atmosphere. CO (carbon monoxide) is an odorless gas produced by the combustion of coal. It is commonly called carbon monoxide. There are other oxides that do not form salts. Now let's take a closer look at each type of salt-forming oxides.

Basic oxides- These are complex chemical substances related to oxides that form salts upon chemical reaction with acids or acidic oxides and do not react with bases or basic oxides. For example, the main ones include the following: K 2 O (potassium oxide), CaO (calcium oxide), FeO (ferrous oxide).

Let's consider chemical properties of oxides with examples

1. Interaction with water: - interaction with water to form a base (or alkali) CaO+H 2 O = Ca(OH) 2 (a known lime slaking reaction, which releases a large amount of heat!)

2. Interaction with acids: - interaction with acid to form salt and water (salt solution in water) CaO + H 2 SO 4 = CaSO 4 + H 2 O (Crystals of this substance CaSO 4 are known to everyone under the name “gypsum”).

3. Interaction with acid oxides: formation of salt CaO + CO 2 = CaCO 3 (Everyone knows this substance - ordinary chalk!)

Acidic oxides- these are complex chemical substances related to oxides that form salts upon chemical interaction with bases or basic oxides and do not interact with acidic oxides. Examples of acidic oxides can be: CO 2 (well-known carbon dioxide), P 2 O 5 - phosphorus oxide(formed by combustion in air white phosphorus), SO 3 - sulfur trioxide - this substance is used to obtain sulfuric acid.

Chemical reaction with water CO 2 +H 2 O=H 2 CO 3 - this substance is carbonic acid - one of the weak acids, it is added to carbonated water to create gas “bubbles”. With increasing temperature, the solubility of gas in water decreases, and its excess comes out in the form of bubbles. - reaction with alkalis (bases): CO 2 +NaOH=Na 2 CO 3 - the resulting substance (salt) is widely used in the household. Its name - soda ash or washing soda - is an excellent detergent for burnt pots, grease, and burnt marks. I do not recommend working with bare hands! - reaction with basic oxides: CO 2 +MgO=MgCO 3 - the resulting salt is magnesium carbonate - also called “bitter salt”.

Amphoteric oxides- these are complex chemical substances, also related to oxides, which form salts during chemical interaction with acids (or acid oxides) and grounds (or basic oxides). The most common use of the word "amphoteric" in our case refers to metal oxides. Example amphoteric oxides can be: ZnO - zinc oxide (white powder, often used in medicine for making masks and creams), Al 2 O 3 - aluminum oxide (also called “alumina”).

The chemical properties of amphoteric oxides are unique in that they can enter into chemical reactions with both bases and acids. For example: - reaction with an acidic oxide: ZnO + H 2 CO 3 = ZnCO 3 + H 2 O - The resulting substance is a solution of “zinc carbonate” salt in water. - reaction with bases: ZnO+2NaOH=Na 2 ZnO 2 +H 2 O - the resulting substance is a double salt of sodium and zinc.

Obtaining oxides produced in various ways. This can happen through physical and chemical means. The simplest way is the chemical interaction of simple elements with oxygen. For example, the result of the combustion process or one of the products of this chemical reaction are oxides. For example, if a hot iron rod, and not only iron (you can take zinc Zn, tin Sn, lead Pb, copper Cu - basically whatever is at hand) is placed in a flask with oxygen, then a chemical reaction of iron oxidation will occur, which accompanied by a bright flash and sparks. The product of the reaction will be black powder of iron oxide FeO: 2Fe+O 2 =2FeO Chemical reactions with other metals and non-metals are completely analogous, For example: Zinc burns in oxygen to form zinc oxide 2Zn+O 2 =2ZnO The combustion of coal is accompanied by the formation of two oxides at once: carbon monoxide gas and carbon dioxide 2C+O 2 =2CO - formation of carbon monoxide. C+O 2 =CO 2 - formation of carbon dioxide. This gas is formed if there is more than enough oxygen, that is, in any case, the reaction first occurs with the formation of carbon monoxide, and then the carbon monoxide is oxidized, turning into carbon dioxide. Obtaining oxides can be done in another way - by chemical decomposition reaction. For example, to obtain iron oxide or aluminum oxide, it is necessary to calcinate the corresponding bases of these metals: Fe(OH) 2 =FeO+H 2 O 2Al(OH) 3 =Al 2 O 3 +3H 2 O, as well as during the decomposition of individual acids: H 2 CO 3 =H 2 O+CO 2 - decomposition of carbonic acid H 2 SO 3 =H 2 O+SO 2 - decomposition of sulfurous acid Obtaining oxides can be carried out from metal salts with strong heating, for example: CaCO 3 = CaO + CO 2 - calcium oxide (or quicklime) and carbon dioxide are obtained by calcining chalk. Cu(NO 3) 2 = 2CuO + 4NO 2 + O 2 - in this decomposition reaction two oxides are obtained at once: copper CuO (black) and nitrogen NO 2 (it is also called brown gas because of its really brown color). Another way in which oxides can be obtained is redox reactions, for example Cu + 4HNO 3 (conc.) = Cu(NO 3) 2 + 2NO 2 + 2H 2 O S + H 2 SO 4 (conc.) = 3SO 2 + 2H 2 O

Chlorine oxides

The following are known chlorine oxides: Cl 2 O, ClO 2, Cl 2 O 6, Cl 2 O 7. All of them, with the exception of Cl 2 O 7, are yellow or orange in color and are not stable, especially ClO 2, Cl 2 O 6. All chlorine oxides are explosive and are very strong oxidizing agents. Reacting with water, they form the corresponding oxygen-containing And chlorine-containing acids: So, Cl 2 O - acid chlorine oxide hypochlorous acid. Cl 2 O + H 2 O = 2HClO - Hypochlorous acid ClO2 - acid chlorine oxide hypochlorous and hypochlorous acid, since during a chemical reaction with water it forms two of these acids at once: ClO 2 + H 2 O = HClO 2 + HClO 3 Cl 2 O 6 - also acid chlorine oxide perchloric and perchloric acids: Cl 2 O 6 + H 2 O = HClO 3 + HClO 4 And finally, Cl 2 O 7 - colorless liquid - acid chlorine oxide perchloric acid: Cl 2 O 7 + H 2 O = HClO 4

Nitrogen oxides

Nitrogen is a gas that forms 5 different compounds with oxygen - 5 nitrogen oxides. Namely: - N 2 O - nitric oxide. Its other name is known in medicine as laughing gas or nitrous oxide- It is colorless, sweetish and pleasant to the taste of gas. - NO - nitrogen monoxide- a colorless, odorless, tasteless gas. - N 2 O 3 - nitrous anhydride- colorless crystalline substance - NO 2 - nitrogen dioxide. Its other name is brown gas- the gas really has a brown-brown color - N 2 O 5 - nitric anhydride- blue liquid, boiling at a temperature of 3.5 0 C

Of all these listed nitrogen compounds, NO - nitrogen monoxide and NO 2 - nitrogen dioxide are of greatest interest in industry. Nitrogen monoxide(NO) and nitrous oxide N 2 O does not react with water or alkalis. Nitrous anhydride(N 2 O 3) when reacting with water forms a weak and unstable nitrous acid HNO 2, which in air gradually turns into a more stable chemical substance nitric acid. Let's look at some chemical properties of nitrogen oxides: Reaction with water: 2NO 2 + H 2 O = HNO 3 + HNO 2 - 2 acids are formed at once: nitric acid HNO 3 and nitrous acid. Reaction with alkali: 2NO 2 + 2NaOH = NaNO 3 + NaNO 2 + H 2 O - two salts are formed: sodium nitrate NaNO 3 (or sodium nitrate) and sodium nitrite (a salt of nitrous acid). Reaction with salts: 2NO 2 + Na 2 CO 3 = NaNO 3 + NaNO 2 + CO 2 - two salts are formed: sodium nitrate and sodium nitrite, and carbon dioxide is released.

Nitrogen dioxide (NO 2) is produced from nitrogen monoxide (NO) using the chemical reaction of compound c oxygen: 2NO + O 2 = 2NO 2

Iron oxides

Iron forms two oxide: FeO - iron oxide(2-valent) - black powder, which is obtained by reduction iron oxide(3-valent) carbon monoxide according to the following chemical reaction: Fe 2 O 3 +CO --> 2FeO+CO 2 This is a basic oxide that easily reacts with acids. It has reducing properties and quickly oxidizes into iron oxide(3-valent). FeO +O 2 --> 2Fe 2 O 3 Iron oxide(3-valent) - red-brown powder (hematite), which has amphoteric properties (can interact with both acids and alkalis). But the acidic properties of this oxide are so weakly expressed that it is most often used as basic oxide. There are also so-called mixed iron oxide Fe 3 O 4 . It is formed when iron burns, conducts electricity well and has magnetic properties (it is called magnetic iron ore or magnetite). If iron burns, then as a result of the combustion reaction, scale is formed, consisting of two oxides: iron oxide(III) and (II) valence.