Caesium superoxide

A 20 g sample, prepared and stored in a dry box for several months, developed a thin crust of oxidation/hydrolysis products. When the crust was disturbed, a violent explosion occurred, later estimated as equivalent to 230 g TNT. A weaker explosion was observed with potassium tetrahydroaluminate. The effect was attributed to superoxidation of traces of metallic potassium, and subsequent interaction of the hexahydroaluminate and superoxide after frictional initiation. Precautions advised include use of freshly prepared material, minimal storage in a dry diluent under an inert atmosphere and destruction of solid residues. Potassium hydrides and caesium hexahydroaluminate may behave similarly, as caesium also superoxidises in air. 

The metals burn in oxygen to yield (i) lithium monoxide, (ii) sodium peroxide and (hi) pota.ssium, rubidium and caesium superoxidcs (p. 384). Successive additions of oxygen giv e the oxide (O ), peroxide (02 ) and superoxide (Og") anions ... 

Potassium, rubidium and caesium also form oxides of the composition M2O3. When white KgOg is heated in oxygen at very low pressure red K2O3 is produced. The magnetic susceptibilities of RbgOg and CsgOg are consistent with the presence of superoxide ions, Og , and peroxide ions, Og , in the proportion 2 1. 

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