<Dd> 2 Rb + 2 RbOH → 2 Rb O + H </Dd> <P> Metallic Rb reacts with O, as indicated by its tendency to rapidly tarnish in air . The tarnishing process is relatively colorful as it proceeds via bronze - colored Rb O and copper - colored Rb O . The suboxides of rubidium that have been characterized by X-ray crystallography include Rb O and Rb O, as well as the mixed Cs - Rb suboxides Cs O Rb (n = 1, 2, 3). </P> <P> The final product of oxygenation of Rb is principally RbO, rubidium superoxide: </P> <Dl> <Dd> Rb + O → RbO </Dd> </Dl>

Predominant product when rb is allowed to react with o2