Ammonium metavanadate

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.[1]

Ammonium vanadate
Names
IUPAC name
Ammonium trioxovanadate(V)
Other names
Ammonium vanadate
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.029.329
RTECS number
  • YWD875000
UNII
Properties
NH4VO3
Molar mass 116.98 g/mol
Appearance white
Density 2.326 g/cm3
Melting point decomposes > 70 °C (158 °F; 343 K)
Boiling point decomposes
Solubility diethanolamine, ethanolamine
Hazards
Main hazards possible mutagen, dangerous for the environment
GHS pictograms
GHS Signal word Danger
H301, H332, H340, H361, H370, H372, H402, H412
P201, P202, P260, P261, P264, P270, P271, P273, P281, P301+310, P304+312, P304+340, P307+311, P308+313, P312, P314, P321, P330, P405, P501
NFPA 704 (fire diamond)
Flammability code 0: Will not burn. E.g. waterHealth code 4: Very short exposure could cause death or major residual injury. E.g. VX gasReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
0
4
0
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
58.1 mg/kg, oral (rat)
Related compounds
Other anions
 Ammonium orthovanadate
Ammonium hexavanadate
Other cations
 Sodium metavanadate
Potassium metavanadate
Related compounds
 Vanadium pentoxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

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.[2][3] This precipitation step can be slow.

The compound 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.[4]

ball-and-stick model
polyhedral model
[(VO3)n]n− chains

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:[1]

2 NH4VO3 → V2O5 + 2 NH3 + H2O

Other

Vanadates can behave as structural mimics of phosphates, and in this way they exhibit biological activity.[5][6]

Ammonium metavanadate is used to prepare Mandelin reagent, a qualitative test for alkaloids.

References
  1. 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. doi:10.1002/14356007.a27_367
  2. G. Brauer "Ammonium Metavanadate" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 1272.
  3. Robert H. Baker, Harry Zimmerman, R. N. Maxson "Ammonium Metavanadate" Inorganic Syntheses, 1950, Vol. 3, 117-118. doi:10.1002/9780470132340.ch30
  4. Vladimír Syneček and František Hanic (1954). "The crystal structure of ammonium metavanadate". Czechoslovak Journal of Physics. 4 (2): 120–129. Bibcode:1954CzJPh...4..120S. doi:10.1007/BF01687750.
  5. Korbecki, Jan; Baranowska-Bosiacka, Irena; Gutowska, Izabela; Chlubek, Dariusz "Biochemical and medical importance of vanadium compounds" Acta Biochimica Polonica 2012, vol. 59, pp. 195-200.
  6. Crans, D. C.; Chatterjee, P. B. "Vanadium Biochemistry" Reedijk, Jan; Poeppelmeier, Kenneth, Eds. Comprehensive Inorganic Chemistry II (2013), 3, 323-342. doi:10.1016/B978-0-08-097774-4.00324-7
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