Ozonide


Ozonide is the unstable, reactive polyatomic anion analog of ozone or any of several classes of organic peroxide compounds similarly formed by the reaction of ozone with an unsaturated compound.

Ionic ozonides

Inorganic ozonides are dark red ionic compounds containing the reactive anion. The anion has the bent shape of the ozone molecule.
Inorganic ozonides are formed by burning potassium, rubidium, or caesium in ozone, or by treating the alkali metal hydroxide with ozone; if potassium is left undisturbed in air for years it accumulates a covering of superoxide and ozonide. They are very sensitive explosives that have to be handled at low temperatures in an atmosphere consisting of an inert gas. Lithium and sodium ozonide are extremely unstable and must be prepared by low-temperature ion exchange starting from CsO3. Sodium ozonide,, which is prone to decomposition into NaOH and sodium superoxide|, was previously thought to be impossible to obtain in pure form. However, with the help of cryptands and methylamine, pure may be obtained as red crystals isostructural to sodium nitrite|.
Ionic ozonides are being investigated as sources of oxygen in chemical oxygen generators. Tetramethylammonium ozonide, which can be made by a metathesis reaction with caesium ozonide in liquid ammonia, is stable up to 348K:

Covalent singly bonded structures

Phosphite ozonides, 3PO3, are used in the production of singlet oxygen. They are made by ozonizing a phosphite ester in dichloromethane at low temperatures, and decompose to yield singlet oxygen and a phosphate ester:
  1. 3P + O3 → 3PO3
  2. 3PO3 → 3PO + 1O2

    Molozonides

Organic ozonides are called molozonides and are typically formed by the addition reaction between ozone and alkenes. They are more explosive cousins of the organic peroxides and as such are rarely isolated during the course of the ozonolysis reaction sequence. Molozonides are unstable and rapidly convert to the trioxolane ring structure with a five-membered C–O–O–C–O ring. They usually appear in the form of foul-smelling oily liquids, and rapidly decompose in the presence of water to carbonyl compounds: aldehydes, ketones, peroxides.
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