Molybdic acid

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Molybdic acid
Other names
Molybdic(VI) acid
ChemSpider 74188
EC Number 231-970-5
Jmol 3D model Interactive image
PubChem 82208
Molar mass 161.95 g mol−1 [1]
Density 3.1 g cm−3 [1]
Melting point 300 °C (572 °F; 573 K)[1]
1510 mg dm−3 [2]
R-phrases R36/37/38 [1]
S-phrases S24/25, S22 [1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Molybdic acid refers to solid, hydrated forms of molybdenum trioxide and species in aqueous solution.

The simplest solid form, the monohydrate, is MoO3·H2O, though the dihydrate (MoO3·2H2O) is also known. The solid state structure of MoO3·H2O consists of layers of octahedrally coordinated MoO5·(H2O) units where 4 vertices are shared.[3] The dihydrate has the same layer structure with the extra H2O molecule intercalated between the layers.

In aqueous solutions of acidified molybdate salts low concentration molecular O3Mo·3H2O has been characterised spectroscopically.[4]

The salts of molybdic acid are called molybdates.

Molybdic acid and its salts are used to make the Froehde reagent for the presumptive identification of alkaloids.


  1. ^ a b c d e "Molybdic acid | 7782-91-4". Retrieved 2012-08-23. 
  2. ^
  3. ^ Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN 0-19-855370-6
  4. ^ Solution structure of molybdic acid from Raman spectroscopy and DFT analysis, Oyerindea O.F., Week C.L., Anbarb A.D., Spiro T.G. Inorganica Chimica Acta, 361, 4, (2008), 1000-1007, doi:10.1016/j.ica.2007.06.025