Hydrated Palladium Sesquioxide, Pd₂O₃

Hydrated Palladium Sesquioxide, Pd₂O₃.xH₂O, is conveniently prepared by electrolytic oxidation of palladous nitrate. This is effected by cooling a concentrated solution to 8° C., and electrolysing with a current density of 0.5 amperes per sq. cm. It may also be obtained by ozonising a solution of palladous nitrate.

The hydrated sesquioxide is thrown out as a brown precipitate which may be washed quite pure with ice-cold water. It is unstable, readily soluble in hydrochloric acid, yielding an unstable solution containing palladium trichloride.