Oxides or oxides are compoundsdifferent 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 oxides of all halogens. Four substances are known, molecules of which contain chlorine and oxygen.
- Gaseous compound from yellow toreddish color with a characteristic smell (like the smell of Cl2 gas) - chlorine oxide (I). The formula is chemical Cl2O. Melting point minus 116 ° C, boiling point plus 2 ° C. Under normal conditions, its density is 3.22 kg / m³.
- Yellow or yellow-orange gas with a characteristic odor - chlorine oxide (IV). Chemical formula ClO2. Melting point minus 59 ° C, boiling point plus 11 ° C.
- Red-brown liquid is chlorine (VI) oxide. The formula is chemical Cl2O6. The melting point is plus 3.5 ° C, the boiling point plus 203 ° C.
- Colorless oily liquid - chlorine oxide (VII). Formula Chemical Cl2O7. The melting point is minus 91.5 ° C, the boiling point is plus 80 ° C.
Chlorine oxide with an oxidation state of +1 isanhydride of a weak monoacid hypochlorous acid (HClO). It is obtained by the Peluse method by the interaction of mercury oxide with gaseous chlorine by one of the reaction equations: 2Cl2 + 2HgO → Cl2O + Hg2OCl2 or 2Cl2 + HgO → Cl2O + HgCl2. The conditions of these reactions are different. Chlorine oxide (I) is condensed at minus 60 ° C, because at higher temperatures it decomposes, explodes, and in concentrated form is explosive. An aqueous solution of Cl2O is obtained by chlorinating in water alkaline earth or alkali metal carbonates. Oxide is highly soluble in water, and hypochlorous acid is formed: Cl2O + H2O ↔ 2HClO. In addition, it also dissolves in carbon tetrachloride.
Oxide of chlorine with oxidation state +4 otherwisecalled dioxide. This substance is soluble in water, sulfuric and acetic acids, acetonitrile, carbon tetrachloride, as well as in other organic solvents, with increasing polarity of which its solubility increases. Under laboratory conditions, it is obtained by reacting potassium chlorate with oxalic acid: 2KClO3 + H2C2O4 → K2CO3 + 2ClO2 + CO2 + H2O. Since chlorine (IV) oxide is an explosive substance, it can not be stored in solution. For these purposes, silica gel is used, on the surface of which, in an adsorbed form, ClO2 can be stored for a long time, while it is possible to get rid of contaminating chlorine impurities, 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, for example, paper or cellulose, etc., as well as for sterilization and disinfection of various materials.
Chlorine oxide with an oxidation state of +6, withmelting decomposes according to the reaction equation: Cl2O6 → 2ClO3. The chlorine (VI) oxide is obtained by oxidizing with ozone dioxide: 2O3 + 2ClO2 → 2O2 + Cl2O6. This oxide is able to react with solutions of alkalis and with water. Disproportionation reactions occur. For example, when reacting with potassium hydroxide: 2KOH + Cl2O6 → KClO3 + KClO4 + H2O, chlorate and potassium perchlorate are obtained as a result.
The highest chlorine oxide is also called chlorine anhydrideor dichloroheptaoxide is a strong oxidant. It is capable of blowing up or heating up. 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 dissolve slowly in cold water, resulting in the formation of perchloric acid: H2O + Cl2O7 → 2HClO4. The dichloroheptoxide is prepared by gently heating the perchloric acid with phosphoric anhydride: P4O10 + 2HClO4 → Cl2O7 + H2P4O11. Also, Cl2O7 can be obtained using oleum instead of phosphorus anhydride.
The section of inorganic chemistry that studiesoxides of halogens, including chlorine oxides, in recent years began to develop actively, since these compounds are energy-intensive. They are able to give energy instantly to the combustion chambers of jet engines, and in chemical sources of current the rate of its recoil 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.
