Related compounds Formula NH4VO3 Density 2.33 g/cm³ | Molar mass 116.98 g/mol Melting point 200 °C Appearance white | |
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Making ammonium metavanadate used to make mandelin reagent for drug testing
Ammonium metavanadate is the inorganic compound with the formula NH4VO3. It is a white solid, although samples are often yellow owing to impurities of V2O5. It is an important intermediate in the purification of vanadium.
Contents
Synthesis of ammonium metavanadate
Synthesis and structure
The compound is prepared by the addition of ammonium salts to solutions of vanadate, generated by dissolution of V2O5 in base. The compound precipitates as a colorless solid.
It adopts a polymeric structure consisting of chains of [VO3]-, formed as corner-sharing VO4 tetrahedra. These chains are interconnected via hydrogen bonds with ammonium ions.
Uses
Vanadium is often purified from aqueous extracts of slags and ore by selective precipitation of ammonium metavanadate. The material is then roasted to give vanadium pentoxide:
2 NH4VO3 → V2O5 + 2 NH3 + H2OOther
Vanadates can behave as structural mimics of phosphates, and in this way they exhibit biological activity.
Ammonium metavanadate is used to prepare Mandelin reagent, a qualitative alkaloid test.