Niobium peroxyfluorides

Niobium Peroxyfluorides or Fluoroxyperniobates.—Like niobic acid, the alkali niobium oxyfluorides have the property of taking up active oxygen by reaction with hydrogen peroxide. 

Rubidium Niobium Peroxyfluoride or rubidium fluoroxypemiobate, RbgNbOjFsHgO or 2RbF.NbOaFs.HaO, is obtained similarly, as thin, yellow plates, from rubidium niobium oxyfluoride, 2RbF.NbOFs.8... 

The pentoxides of vanadium, niobium, and tantalum react with hydrogen peroxide to produce per-acids of the general formula HR04. H20. These per-acids increase in stability with increase in atomic weight. Pertantalic acid is a white solid which can be heated to 100° C. without undergoing decomposition. The oxyfluorides of these metals also take up active oxygen to yield peroxyfluorides, which are much better defined in the case of niobium and tantalum than with vanadium. 

Vanadium oxyfluorides also react with hydrogen peroxide to yield complex compounds.2 These are not so well defined as in the case of the peroxyfluorides of niobium and tantalum. 

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