Sodium molybdate

From Sciencemadness Wiki
Jump to: navigation, search
Sodium molybdate
Sodium molybdate dihydrate sample bag.jpg
Sodium molybdate crystals and original package
IUPAC name
Sodium molybdate
Other names
Disodium molybdate
Disodium tetraoxomolybdate
Sodium molybdate(VI)
Sodium orthomolybdate
Na2MoO4·2H2O (dihydrate)
Molar mass 205.92 g/mol (anhydrous)
241.95 g/mol (dihydrate)
Appearance White solid
Odor Odorless
Density 3.78 g/cm3
Melting point 687 °C (1,269 °F; 960 K)
Boiling point Decomposes
84 g/100 ml (100 °C)
Solubility Insoluble in hydrocarbons
Vapor pressure ~0 mmHg
Safety data sheet Sigma-Aldrich
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
4,000 mg/kg (rat, oral)
>2,080 mg/m3 (rat, 4 hr)
Related compounds
Related compounds
Ammonium heptamolybdate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Sodium molybdate (Na2MoO4) is chemical compound, useful as a readily source of molybdenum. It is often encountered as the dihydrate form Na2MoO4·2H2O.



Sodium molybdate will react energetically with interhalogens (bromine pentafluoride, chlorine trifluoride, etc.).

Its reaction with hot sodium, potassium or lithium is incandescent and violent.

When reacted with sodium borohydride, molybdenum is reduced to a lower valent oxide:[1]

Na2MoO4 + NaBH4 + 2 H2O → NaBO2 + MoO2 + 2 NaOH + 3 H2


Sodium molybdate is a white crystalline solid, soluble in water, but insoluble in most organic solvents.


Sodium molybdate is sold as fertilizer for plants, and is available at many gardening stores, though it's a bit more expensive than most common fertilizers.

It can also be purchased from lab suppliers, online.


Sodium molybdate can be prepared by dissolving MoO3 in an aq. solution of sodium hydroxide, at 50–70 °C and crystallizing the filtered product from the solution.

MoO3 + 2 NaOH + H2O → Na2MoO4·2H2O

The anhydrous salt is prepared by heating the dihydrate to 100 °C.


  • Source of molybdenum
  • Fertilizer



Sodium molybdate has low toxicity. Inhalation may cause irritation of nose and lungs.

Sodium molybdate will react extremely violent and may even explode with many molten metals, like magnesium, alkali metals.


In closed bottles


No special disposal is required.


  1. Chi Fo Tsang and Arumugam Manthiram. Journal of Materials Chemistry 1997. 7(6). 1003–1006.

Relevant Sciencemadness threads