Synthesis of metaperoxoniobates of the alkaline earth metals

1. The reaction of the metaniobates of magnesium, calcium and strontium with hydrogen peroxide at 20°, independent of the H2O2 concentration (6–25%), yields the previously unknown metaperoxoniobates of magnesium, calcium and strontium of composition (Mg, Ca, Sr) (NbO4)2·nH2O2 mH2O (n=1.3-2; m=5-7). In the air, and when heated up to 100°, they are unstable and decompose with the liberation of active oxygen from the crystallization hydrogen peroxide and change over to the stable metaperoxoniobates Me(NbO4)2·nH2O (n=3-4). 2. The thermal decomposition of the peroxo compounds of the alkaline earth metals at 400° yields the pure anhydrous meta salts, which in the ignited state react with difficulty with hydrogen peroxide solutions.