Preparation
Cesium peroxides have been prepared by carefully controlled oxidation of the metals with the exact amount of air or nitric oxide, but it is difficult to prepare the pure peroxides in this manner because of the ease with which the peroxides are oxidized to the superoxide. They can also be prepared by careful oxidation of liquid ammonia solutions of the metals, using the stoichiometric quantity of oxygen for peroxide formation. They can also be prepared by the thermal decomposition of the superoxides in vacuum.
