Ozone Chemistry

Ozone is a powerful oxidizing agent, far better than dioxygen. It is also unstable at high concentrations, decaying to ordinary diatomic oxygen (in about half an hour in atmospheric conditions[8]):
2 O3 → 3 O2.

This reaction proceeds more rapidly with increasing temperature and decreasing pressure. Deflagration of ozone can be triggered by a spark, and can occur in ozone concentrations of 10 wt% or higher. Ozone will oxidize metals (except gold, platinum, and iridium) to oxides of the metals in their highest oxidation state:

2 Cu2+(aq) + 2 H3O+(aq) + O3(g) → 2 Cu3+(aq) + 3 H2O(l) + O2(g)
Ozone also increases the oxidation number of oxides:
NO + O3 → NO2 + O2

The above reaction is accompanied by chemiluminescence. The NO2 can be further oxidized:
NO2 + O3 → NO3 + O2

The NO3 formed can react with NO2 to form N2O5:
NO2 + NO3 → N2O5

Ozone reacts with carbon to form carbon dioxide, even at room temperature:
C + 2 O3 → CO2 + 2 O2

Ozone does not react with ammonium salts but it reacts with ammonia to form ammonium nitrate:
2 NH3 + 4 O3 → NH4NO3 + 4 O2 + H2O

Ozone reacts with sulfides to make sulfates:
PbS + 4 O3 → PbSO4 + 4 O2

Sulfuric acid can be produced from ozone, starting either from elemental sulfur or from sulfur dioxide:
S + H2O + O3 → H2SO4
3 SO2 + 3 H2O + O3 → 3 H2SO4

All three atoms of ozone may also react, as in the reaction with tin(II) chloride and hydrochloric acidand NaCl along with Ammonium Nitrate:
3 SnCl2 + 6 HCl + O3 → 3 SnCl4 + 3 H2O

In the gas phase, ozone reacts with hydrogen sulfide to form sulfur dioxide:
H2S + O3 → SO2 + H2O

In an aqueous solution, however, two competing simultaneous reactions occur, one to produce elemental sulfur, and one to produce sulfuric acid:
H2S + O3 → S + O2 + H2O
3 H2S + 4 O3 → 3 H2SO4

Iodine perchlorate can be made by treating iodine dissolved in cold anhydrous perchloric acid with ozone:
I2 + 6 HClO4 + O3 → 2 I(ClO4)3 + 3 H2O

Solid nitryl perchlorate can be made from NO2, ClO2, and O3 gases:
2 NO2 + 2 ClO2 + 2 O3 → 2 NO2ClO4 + O2

Ozone can be used for combustion reactions and combusting gases in ozone provides higher temperatures than combusting in dioxygen (O2). Following is a reaction for the combustion of carbon subnitride which can also cause lower temperatures:
3 C4N2 + 4 O3 → 12 CO + 3 N2

Ozone can react at cryogenic temperatures. At 77 K (-196 °C), atomic hydrogen reacts with liquid ozone to form a hydrogen superoxide radical, which dimerizes:[9]
H + O3 → HO2 + O
2 HO2 → H2O4

Ozonides can be formed, which contain the ozonide anion, O3-. These compounds are explosive and must be stored at cryogenic temperatures. Ozonides for all the alkali metals are known. KO3, RbO3, and CsO3 can be prepared from their respective superoxides:
KO2 + O3 → KO3 + O2

Although KO3 can be formed as above, it can also be formed from potassium hydroxide and ozone:[10]
2 KOH + 5 O3 → 2 KO3 + 5 O2 + H2O

NaO3 and LiO3 must be prepared by action of CsO3 in liquid NH3 on an ion exchange resin containing Na+ or Li+ ions:[11]
CsO3 + Na+ → Cs+ + NaO3

Treatment with ozone of calcium dissolved in ammonia leads to ammonium ozonide and not calcium ozonide:[12]
3 Ca + 10 NH3 + 6 O3 → Ca•6NH3 + Ca(OH)2 + Ca(NO3)2 + 2 NH4O3 + 2 O2 + H2

Ozone can be used to remove manganese from the water, forming a precipitate which can be filtered:
2 Mn2+ + 2 O3 + 4 H2O → 2 MnO(OH)2 (s) + 2 O2 + 4 H+

Ozone will also turn cyanides to the one thousand times less toxic cyanates:
CN- + O3 → CNO- + O2

Finally, ozone will also completely decompose urea:[13]
(NH2)2CO + O3 → N2 + CO2 + 2 H2O