Halogen Oxides and Oxyacids

Oxides and Oxyacids of Halogens . The halogens are not combined directly with oxygen , but it is possible to obtain their oxides by indirect methods. Fluorine and bromine oxides have recently been incorporated into this group of compounds. The most important are the oxides of fluorine, chlorine, bromine and iodine .


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  • 1 General characteristics
  • 2 Nomenclature
  • 3 Structures
  • 4 Oxides of halogens
  • 5 Sources

General characteristics

Halogen oxides are not very stable. The opposite occurs in them than in the hydrogenated compounds, since the stability increases here from fluorine to iodine, with the exception of that of bromine oxides. Furthermore, as the oxygen content in the series of compounds of each halogen increases, the stability increases; thus ClO4H is more stable than ClO3H.

No fluorine oxacids are known although the preparation under special conditions of fluorine saline compounds of an oxidizing nature has been indicated. The other halogens form various oxacids in which the halogen exists in various states of [[oxidation] +. As the proportion of oxygen increases, the covalence of the halogen increases, that is, its oxidation or valence number.


Prefixes and suffixes are used to distinguish between the various oxacids of an element. In halogen hydracids, the suffix of binary acid (two elements) is hydric, meaning that there is no oxygen in the acid molecule . When an element forms two oxacids, such as SO3H2 and SO4H2, the derivative of the upper oxide has the suffix ico, and the lower one the bear, and therefore SO4H2, coming from SO3 (SO3 + H2O = SO4H2), is the acid sulfuric; and SO3H2, derived from SO2 (SO2 + H2O = SO3H2), is sulfurous acid. The suffixes ico and bear are also used, as indicated, to designate the upper and lower valence of an element in a saline compound, such as ferric chloride, Cl3Fe, and ferrous chloride, Cl2Fe, and its use first, later spread to acids.


Chloride and perchlorate ions have complete electronic structures, which explains the greater stability of these ions in relation to the anions of the other chlorine acids.

Halogen oxides

  • The oxide fluorine. It is an unstable gas that is formed by bubbling fluorine under special conditions through a dilute solution of sodium hydroxide.
  • Chlorine monoxide. It is an unstable yellow gas, obtained by distilling hypochlorous acid under reduced pressure, or by passing chlorine over mercuric oxide .
  • Chlorine dioxide. It is a reddish yellow gas that is formed when the chlorite acid decomposes. It is very explosive, and breaks down into chlorine and oxygen when heated slightly. Due to the violence of this reaction it is very dangerous to add sulfuric acid or another strong acid to a chlorate or to a mixture that contains it in a dry state.


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