Sodium molybdate
2845369
221109664
2008-06-23T02:28:57Z
Steviedpeele
1322814
replaced image of the structure with one that was more clearer and of higher quality
{{Chembox new
| Name = Sodium molybdate
| ImageFile = Sodium molybdate.jpg
| ImageFile1 = Sodiummolybdate.png
| ImageName = Sodium molybdate
| IUPACName = Sodium molybdate(VI)
| OtherNames = Disodium molybdate.
| Section1 = {{Chembox Identifiers
| CASNo = 7631-95-0
}}
| Section2 = {{Chembox Properties
| Formula = Na<sub>2</sub>MoO<sub>4</sub>
| MolarMass = Anhydrous 206 g/mol
Dihydrate 241.95 g/mol
| Appearance = White powder.
| Density = 3.78 g/cm<sup>3</sup>, solid
| Solubility = 65.5 g/100 g Water
| MeltingPt = 687°C
| BoilingPt = }}
| Section7 = {{Chembox Hazards
| ExternalMSDS = [http://ptcl.chem.ox.ac.uk/MSDS/SO/sodium_molybdate.html External MSDS]
| EUClass = Irritant ('''I''')
| RPhrases = {{R36}}, {{R37}}, {{R38}}.
| SPhrases = None listed.
| FlashPt = Non-flammable.
}}
| Section8 = {{Chembox Other
| OtherAnions = None listed.
| OtherCations = None listed.
| Function = [[base (chemistry)|base]]s }}
}}
'''Sodium molybdate''', Na<sub>2</sub>MoO<sub>4</sub>, is useful as a source of [[molybdenum]].{{Fact|date=March 2008}} It is often found as the dihydrate, Na<sub>2</sub>MoO<sub>4</sub>·2H<sub>2</sub>O.
The molybdate(VI) anion is tetrahedral. Two sodium cations coordinate with every one anion.<ref name = Braithwaite>Braithwaite, E.R.; Haber, J. ''Molybdenum: An outline of its Chemistry and Uses.'' 1994. Elsevier Science B.V. Amsterdam, The Netherlands.</ref>
==History==
Sodium molybdate was first synthesized by the method of hydration.<ref>Spitsyn, Vikt. I.; Kuleshov, I. M. ''Zhurnal Obshchei Khimii'' 1951. 21. 1701-15. </ref>; A more convenient synthesis is done by dissolving [[Molybdenum(VI) oxide|MoO<sub>3</sub>]] in [[sodium hydroxide]] at 50-70 °C and crystallizing the filtered product.<ref name = Braithwaite/> The anhydrous salt is prepared by heating to 100 °C.
:MoO<sub>3</sub> + 2NaOH → Na<sub>2</sub>MoO<sub>4</sub>·2H<sub>2</sub>O
==Uses==
Sodium molybdate is used in biochemistry and medicinal chemistry to track various organic chemicals that are colorless after a chromatographical procedure, which it always stains blue. The blue color is also called [[molybdenum blue]].
The agriculture industry uses 1 million pounds per year as a fertilizer. However, care must be taken because at a level of 0.3 ppm sodium molybdate can cause copper deficiencies in animals, particularly cattle.<ref name = Braithwaite/>
It is used for water treatment.{{Fact|date=March 2008}}
It is used in industry for corrosion inhibition, as it is a non-oxidizing anodic inhibitor.<ref name = Braithwaite/> The addition of sodium molybdate significantly reduces the nitrite requirement of fluids inhibited with nitrite-amine, and improves the corrosion protection of carboxylate salt fluids.<ref>Vukasovich, Mark S. ''Lubrication Engineering'' 1980. 36(12). 708-12. </ref>
According to an article from 1950 that was published in Nature, sodium molybdate is useful for curing a broccoli disease known as ‘whiptail’.{{Fact|date=March 2008}}
==Reactions==
When reacted with [[sodium borohydride]], molybdenum is reduced to a lower valent oxide:<ref>Chi Fo Tsang and Arumugam Manthiram. ''Journal of Materials Chemistry'' 1997. 7(6). 1003–1006.</ref>
:Na<sub>2</sub>MoO<sub>4</sub> + NaBH<sub>4</sub> + 2H<sub>2</sub>O→ NaBO<sub>2</sub> + MoO<sub>2</sub>+2NaOH+ 3 H<sub>2</sub>
Sodium molybdate reacts with the acids of dithiophosphates:<ref name = Braithwaite/>
:Na<sub>2</sub>MoO<sub>4</sub> + (RO)<sub>2</sub>PS<sub>2</sub>H (R = Me, Et) → [MoO<sub>2</sub>(S<sub>2</sub>P(OR)<sub>2</sub>)<sub>2</sub>]
which further reacts to form [MoO<sub>3</sub>(S<sub>2</sub>P(OR)<sub>2</sub>)<sub>4</sub>].
==Precautions==
Sodium molybdate is incompatible with alkali metals, most common metals and oxidizing agents. It will explode on contact with molten magnesium. It will violently react with interhalogens (e.g., bromine pentafluoride; chlorine trifluoride). Its reaction with hot sodium, potassium or lithium is incandescent.{{Fact|date=March 2008}}
==References==
{{reflist}}
==See also==
* [[xanthine oxidase]]
==External links==
* [http://lpi.oregonstate.edu/infocenter/minerals/molybdenum/ Linus Pauling Institute page on molybdenum].
[[Category:Molybdates]]
[[Category:Sodium compounds]]
[[Category:Dietary minerals]]
[[Category:Inorganic compounds]]
[[ar:موليبدات صوديوم]]