Oxides, peroxides, superoxides, suboxides and ozonides

When the group 1 metals are heated in an excess of air or in O2, the principal products obtained depend on the metal lithium oxide, Li20 (eq. 11.8), sodium peroxide, Na202 (eq. 11.9), and the superoxides KO2, Rb02 and CSO2 (eq. 11.10). 

The alkali metal oxides, peroxides and superoxides react with water according to eqs. 11.11-11.13. One use ofK02 is in breathing masks where it absorbs H2O producing O2 for respiration and KOH, which absorbs exhaled CO2 (reaction 11.14). 

Sodium peroxide reacts with CO2 to give Na2C03, making it suitable for use in air purification in confined spaces (e.g. in submarines) KO2 acts similarly but more effectively. 

Although all the group 1 peroxides decompose on heating according to equation 11.15, their thermal stabilities depend on cation size. Li202 is the least stable peroxide, while CS2O2 is the most stable. The stabilities of the superoxides with respect to decomposition to M2O2 and O2 follow a similar trend. 

An ion-exchange resin consists of a solid phase (e.g. a zeolite) which contains acidic or basic groups which may exchange with cations or anions, respectively, from solutions washed through the resin an important application is in water pmification (see Box 16.3). 

VA Fig. 11.4 The structure of the suboxide CS11O3 consists of three oxygen-centred, face-sharing octahedral units. Colour code Cs, blue O, red. 

---