Hydrazinium metavanadate

In a slightly different method, hydrazinium metavanadate (a brown amorphous solid) is prepared by the addition of solid ammonium metavanadate (NH4VO3) to hydrazine hydrate at 0°C using an ice-salt mixture as this reaction is highly exothermic [8]. The compound formed decomposes at room temperature and so a lower temperature is always maintained during its preparation. In addition, the vanadate ion (VO3 ) is known to oxidize hydrazine, but this is considerably suppressed if the reaction is conducted at a low temperature. Furthermore, it is extremely difficult to recrystallize hydrazinium metavanadate as it is insoluble in water. 

In the IR spectrum of hydrazinium metavanadate, apart from the z/n-n frequency of N2H5+, absorption frequencies of VO3 are seen at 8 70 and 760 cm, confirming the formation of N2H5VO3. 

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