Ammonium metavanadate is the
inorganic compound
An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bondsthat is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''.
Inorgan ...
with the formula NH
4VO
3. It is a white salt, although samples are often yellow owing to impurities of V
2O
5. It is an important intermediate in the purification of vanadium.
[Günter Bauer, Volker Güther, Hans Hess, Andreas Otto, Oskar Roidl, Heinz Roller, Siegfried Sattelberger "Vanadium and Vanadium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. ]
Synthesis and structure
The compound is prepared by the addition of ammonium salts to solutions of vanadate ions, generated by dissolution of
V2O5 in basic aqueous solutions, such as hot sodium carbonate. The compound precipitates as a colourless solid. This precipitation step can be slow.
The compound adopts a polymeric structure consisting of chains of
3">O3sup>−, formed as corner-sharing VO
4 tetrahedra. These chains are interconnected via
hydrogen bond
In chemistry, a hydrogen bond (H-bond) is a specific type of molecular interaction that exhibits partial covalent character and cannot be described as a purely electrostatic force. It occurs when a hydrogen (H) atom, Covalent bond, covalently b ...
s with
ammonium
Ammonium is a modified form of ammonia that has an extra hydrogen atom. It is a positively charged (cationic) polyatomic ion, molecular ion with the chemical formula or . It is formed by the protonation, addition of a proton (a hydrogen nucleu ...
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 + H2O
]
Other
Vanadates can behave as structural mimics of phosphates, and in this way they exhibit biological activity.[Crans, D. C.; Chatterjee, P. B. "Vanadium Biochemistry" Reedijk, Jan; Poeppelmeier, Kenneth, Eds. Comprehensive Inorganic Chemistry II (2013), 3, 323-342. ]
Ammonium metavanadate is used to prepare Mandelin reagent, a qualitative test for alkaloid
Alkaloids are a broad class of natural product, naturally occurring organic compounds that contain at least one nitrogen atom. Some synthetic compounds of similar structure may also be termed alkaloids.
Alkaloids are produced by a large varie ...
s.
References
{{Vanadium compounds
Vanadates
Ammonium compounds
Inorganic compounds