Chlorine oxide 5 what. Chlorine oxides

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 oxides of chlorine are extremely unstable substances, which is typical for the oxides of all halogens. Four substances are known, the molecules of which contain chlorine and oxygen.

1. A gaseous compound from yellow to reddish in 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 (IV) oxide. Chemical formula ClO2. Melting point minus 59 °C, boiling point plus 11 °C.
3. Red-brown liquid - 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 an oxidation state of +1, is the anhydride of the weak monobasic hypochlorous acid (HClO). It is obtained according to the Pelouse method by the interaction of mercury oxide with gaseous chlorine according to one of the reaction equations: 2Cl2 + 2HgO → Cl2O + Hg2OCl2 or 2Cl2 + HgO → Cl2O + HgCl2. The conditions for these reactions to occur are different. Chlorine oxide (I) is condensed at a temperature of minus 60 ° C, because at a higher temperature it decomposes, exploding, and in a concentrated form it is explosive. An aqueous solution of Cl2O is obtained by chlorination of alkaline earth or alkali metal carbonates in water. The oxide is highly soluble in water, and hypochlorous acid is formed: Cl2O + H2O ↔ 2HClO. In addition, it also dissolves 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, and also in other organic solvents, with an increase in the polarity of which its solubility increases. Under laboratory conditions, it is obtained by the interaction of potassium chlorate with oxalic acid: 2KClO3 + H2C2O4 → K2CO3 + 2ClO2 + CO2 + H2O. Since chlorine (IV) oxide 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, at the same time it is possible to get rid of chlorine impurities that pollute it, 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 bleach, such as paper or cellulose, etc., as well as for sterilization and disinfection of various materials.

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

Higher chlorine oxide is also called chlorine anhydride or dichloroheptoxide is a strong oxidizing agent. It is capable of exploding on impact or when heated. However, this substance is more stable than oxides with an oxidation state of +1 and +4. Its decomposition to chlorine and oxygen is accelerated due to the presence of lower oxides and with an increase in temperature from 60 to 70 ° C. Chlorine oxide (VII) is able to slowly dissolve in cold water; as a result of the reaction, perchloric acid is formed: H2O + Cl2O7 → 2HClO4. Dichloroheptoxide 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 section of inorganic chemistry that studies halogen oxides, including chlorine oxides, has been actively developed in recent years, since these compounds are energy-intensive. They are able to give energy instantly in the combustion chambers of jet engines, and in chemical current sources, the rate of its return 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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Chlorine(I) oxide Cl2O- endothermic unstable compound can be obtained as follows: 2 Cl 2 + HgO \u003d HgCl 2 + Cl 2 O.

When heated, it decomposes: 2Cl 2 O \u003d 2Cl 2 + O 2, with water it gives hypochlorous acid (has a keel character): Cl 2 O + H 2 O \u003d 2HOCl.

The oxidation state of chlorine is +4. ClO2- chlorine oxide (IV), endothermic with a pungent odor, m-la has an angular shape, so it is polar.

ClO 2 is characterized by disproportionation reactions: 6ClO 2 + 3H 2 O \u003d 5HClO 3 + HCl,

2ClO 2 + 2KOH \u003d KClO 2 + KClO 3 + H 2 O. 2KClO 3 + H 2 C 2 O 4 + H 2 SO 4 \u003d K 2 SO 4 + 2CO 2 + 2ClO 2 + 2H 2 O,

Mainly used for bleaching or sterilizing various materials. It has been established that it can be used to dephenolize wastewater from chemical plants.

Cl2O6 gives disproportionation reactions: 2ClO 2 + 2O 3 \u003d Cl 2 O 6 + 2 O 2,

Cl 2 O 6 + 2 KOH \u003d KClO3 + KClO 4 + H 2 O.

Chlorine(VII) oxide Cl2O7- perchloric anhydride HClO 4 (m-l polar), relatively stable, when heated (above 120 degrees) decomposes with an explosion. 2 HClO 4 + P 2 O 5 \u003d Cl 2 O 7 + 2HPO 3,

Cl 2 O 7 + H 2 O \u003d 2HClO 4, 2Cl 2 O 7 \u003d 2Cl 2 + 7O 2,

Bromine (I) oxide can be obtained as follows: 2 Br 2 + HgO \u003d HgBr 2 + Br2O, at room temperature it

decomposes: 2Br 2 O \u003d 2 Br 2 + O 2.

Bromine oxide (IV) 4O 3 + 3Br 2 \u003d 6BrO 2 - light yellow TV in-in, stable only at -40 degrees. One of the products of its thermal decomposition in vacuum is brown bromine oxide.

Iodine oxide (V) is obtained by dehydration of iodic acid (with sulfuric acid when heated): 2 HIO 3 \u003d I 2 O 5 + H 2 O, above 3000 C it decomposes: 2 I 2 O 5 \u003d 2 I 2 + 5 O 2.

Question No. 20. Oxygen-containing acids of halogens of the HCO type and their salts. Nomenclature. The structure of m-l. Sustainability. Oxidizing and acidic properties. Bleaching powder. Receipt and application.

Hypochlorous acid partly formed by the interaction of a slow current of fluorine under reduced pressure with chilled water. Selected only in very small quantities, it is a colorless substance with a high vapor pressure, under normal conditions it decomposes quite quickly into HF and O 2. M-la HOF has an angle = 97 degrees. It is, apparently, a strong one, but it is rapidly hydrolyzed by water, mainly according to the equation: HOF + HOH = HF + H 2 O 2. Its salts have not been obtained, but substances are known, which can be considered as products of substitution of its hydrogen for metalloid radicals.

Hypochlorous acid very weak, easily decomposes in the light with the release of atomic oxygen, which determines its very strong oxidizing properties.

HClO and hypochlorites can be obtained as follows: Cl 2 + H 2 O \u003d HCl + HClO, Cl 2 + 2KOH \u003d KCl + KClO + H 2 O javelin water, Cl 2 + Ca (OH) 2 \u003d CaOCl 2 + H 2 O - chlorine lime Cl 2 O + 2 KOH = 2KClO + H 2 O,

2 HI + HClO \u003d I 2 + HCl + H 2 O. Cl 2 O + H 2 O \u003d 2HOCl.

Hypochlorous acid and hypochlorites are ok. Comparison of standard redox potentials shows that hypochlorous acid is a stronger oxidizing agent than free chlorine and hypochlorites. The large oxidizing power of to-you is explained by the strong polarizable effect of the proton on the chlorine-oxygen bond, in the p-those of which the bond is deformed Þ to-that is an unstable formation compared to hypochlorites.

Javel water is used for bleaching fabrics, while bleach is used for disinfection.

M-la has an angular structure angle = 103° d(OH)=0.97, d(ОCl) = 1.69А°.

hypobromous acid Br 2 + H 2 O \u003d HBr + HBrO, Br 2 + KOH \u003d KBr + KBrO + H 2 O, potassium hypobromite Br 2 + 5 Cl 2 + 6 H 2 O \u003d 2 HBrO + 10 HCl. Potassium hypobromite decomposes easily: 3 KBrO = 2 KBr + KBrO 3 potassium bromate.

Iodous acid: 2I 2 + HgO + H 2 O \u003d HgI 2 + 2HIO, Salts can be obtained by reacting acids with alkalis or by reactions:

The last 2 to-you are not isolated in an individual state, and salts - hypobromides and hypoiodides - are quite stable in the absence of vzagisil. In this series, the strength of k-t falls.

Question No. 21 Nomenclature. The structure of m-l. Sustainability. Oxidizing and acidic properties. Receipt and application. Bertolet's salt. The concept of oscillatory p-tions.

Perchloric acid HClO 3 is stable only in aqueous solutions - it is a strong acid and an energetic oxidizing agent: Ba (ClO 3) 2 + H 2 SO 4 \u003d 2 HClO 3 + BaSO 4, 6P + 5HClO 3 \u003d 3 P 2 O 5 + 5 HCl,

HClO 3 + NaOH = NaClO 3 + H 2 O (sodium chlorate).

As the temperature rises, the reaction proceeds: 3 Cl 2 + 6 KOH \u003d 5 KCl + KClO 3 + 3 H 2 O, where KClO 3 is a salt (potassium chlorate), also called Berthollet salt in honor of its discoverer, the French chemist C. Berthollet. It is used as an oxidizing agent in pyrotechnics, in the production of matches, to obtain oxygen in the laboratory. When heated, it decomposes: 4 KClO 3 \u003d KCl + 3 KClO 4, and in the presence of a MnO 2 catalyst, the following occurs: 2 KClO 3 \u003d 2 KCl + 3 O 2.

HBrO 3 - bromic acid (it exists only in solution) can be obtained as follows: Ba (BrO 3) 2 + H 2 SO 4 \u003d 2 HBrO 3 + BaSO 4.

It is interesting to note that iodine can displace bromine from potassium bromate 2 KBrO 3 + I 2 = 2 KIO 3 + Br 2

HIO 3 - iodine (iodates) d (IO) \u003d 1.8 A (two bonds) and 1.9 (one bond) and angle OIO \u003d 98 °

I 2 + 5Cl 2 + 6H 2 O \u003d 2HIO 3 + 10HCl, 3I 2 + 10HNO 3 \u003d 6HIO 3 + 10NO + 2H 2 O,

I 2 + 2HClO 3 = 2HIO 3 + Cl 2 (iodine displaces chlorine), IF 5 + 3 H 2 O = 5 HF + HIO 3

Salts can be obtained by the interaction of acids with alkalis or by the reactions:

3 I 2 + 6 NaOH = 5 NaI + NaIO 3 + 3 H 2 O,

Solubility and acid properties of acids decrease, and stability increases

Author Chemical Encyclopedia b.b. N.S.Zefirov

CHLORINE OXIDES. All CHLORINE OXIDES about. have a pungent odor, are thermally and photochemically unstable, prone to explosive decay, have positive Monoxide [oxide Cl (I), dichloroxide, hemioxide] Cl 2 O - yellow-orange gas with a slight greenish tint, in a liquid state - red-brown; bond length Cl - O 0.1700 nm, angle OSlO 111 °, 2.60 x 10 -30 C x m (table); the equation for the temperature dependence of vapor pressure lgp (mm Hg) \u003d 7.87 - 1373 / T (173-288 K); soluble in water to form NSO, solubility (g in 100 g H 2 O at 0 ° C): 33.6 (2.66 kPa), 52.4 (6.65 kPa). At 60-100 °C thermodynamically, the 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 gives respectively T1OCl 2 , TaOCl 3 and AsO 2 Cl. With NO 2 it forms a mixture of NO 2 Cl and NO 3 Cl, with N 2 O 5 - pure NO 3 Cl. By fluorination of Cl 2 O with AgF 2 one can obtain ClOF 3 , and by reaction with AsF 5 or SbF 5 one can obtain chloryl salts ClO + 2 MF - 6 . They react similarly with MF 5 (where M is As and Sb) ClO 2 and Cl 2 O 6. 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)

*Estimated. **2.38 g/cm3 at -160°C.

ClO 2 dioxide 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, OSlO angle 117 °C; the equation for the temperature dependence of vapor pressure lgp (mm Hg) \u003d 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 an individual state, it is explosive, at 30-50 ° C the decay proceeds at a measurable rate, above 50 C it explodes after an induction period. In an alkaline environment, ClO 2 disproportionates 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 forms NO 3 Cl, with NOCl -NO 2 Cl. Fluorinated with AgF 2 , BrF 3 or dilute 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, by the action Cl 2 for chlorites. Unlike the rest of the CHLORINE OXIDES Fr. ClО 2 is a product of prom. production, it is used instead of Cl 2 as an environmentally safer product for bleaching wood pulp, cellulose, synthetic. fibers, for the preparation of drinking and technol. water, disinfection of sewage. Irritates mucous membranes, causes coughing, vomiting, etc.; MPC in the air of the working area 0.1 mg/m3, LD 50 140 mg/kg (rats, intragastrically).
Chlorine perchlorate (cychlorotetraoxide) Cl 2 O 4, or СlOClО 3 - light yellow liquid, crystalline. almost colorless state (see Perchlorates).
Trioxide (dichlorohexaxide) Cl 2 O 6 is a bright red liquid, orange in the solid state, the color weakens when cooled. In a gas and liquid, the molecules have the structure of O 2 Cl - O - ClO 3, in crystals - crystals of the monoclinic system (space group, z \u003d 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, hydrolysis products - 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 vacuum, such complexes split off Cl 2 O 6 and turn into non-solvated perchlorates Al(ClO 4) 3 , Fe(ClO 4) 3 . Cl 2 O 6 is obtained by the reaction of ozone with ClO 2 or by the action of F 2 on metal chlorates. Used for the synthesis of anhydrous perchlorates in the laboratory.
Cl(VII) oxide (chloric anhydride, dichloroheptoxide) Cl 2 O 7 - colorless. mobile fluid, sensitive to impact and friction. The molecule has the structure of O 3 Cl - O - ClO 3, the bond length Cl - O is 0.1709 nm, in the groups ClO 3 - 0.1405 nm, the angle СlOCl is 118.6 °, OSlO 115.2 °, 2.40 x 10 -30 C x m; monoclinic crystals (space group C 2/c); the equation for the temperature dependence of vapor pressure lgp (mm Hg) = 7.796-1770/T. Unlimitedly soluble in CCl 4, readily soluble in HClO 4, POCl 3, etc. It does not mix with water, reacts at the phase boundary with the formation of HClO 4, the reaction is highly exothermic to the reaction -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 proceeds 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, respectively, RHNClO 3 and R 2 NClO 3, with SbF 5 - SbOF 3 and FClO 3, with N 2 O 5 in CCl 4 NO 2 ClO 4 . Using Cl 2 O 7, organic perchlorates can be synthesized 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 a solution of HClO 4 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 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, - СlО 3 , СlОО, СlСlО, as well as the low-stable sesquioxide Сl 2 О 3 , which decomposes at -50 - 0 ° С and probably has the structure of chlorine chlorate СloClO 2 . The thermally stable ClO radical (bond length Cl - O 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.

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