Sodium metavanadate

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   Sodium metavanadate   
Names: sodium metavanadate
sodium vanadate
sodium trioxovanadate

Formula: NaVO3 (anhydrous)
NaVO3 · 2H2O (dihydrate)
SMILES: [O-][V](=O)=O.[Na+]
Molar mass: 121.929 g/mol (anhydrous)
157.959 g/mol (dihydrate)
Density: 2.85 g/cm3 (anhydrous)
2.79 g/cm3 (dihydrate)
Crystal system: monoclinic (anhydrous)
a=10.552 Å, b=9.468 Å, c=5.879 Åα=90°, β=108.47°, γ=90°
orthorhombic (dihydrate)
a=14.147 Å, b=3.6496 Å, c=5.364 Åα=90°, β=90°, γ=90°
Shapes:
https://en.crystalls.info/w/uploads/media/Spherolit.json
https://en.crystalls.info/w/uploads/media/Needle.json

Color: colorless
pale yellow surface
shimmers in the light
Melting point: 632 °C905.15 K <br />1,169.6 °F <br />1,629.27 °R <br /> (anhydrous)
Magnetic properties: diamagnetic
Stability: stable (monohydrate)
slightly hygroscopic (anhydrous)
Hardness: fragile
Toxicity: highly toxic
LD50=98mg/kg

Description

Inorganic compound, salt of alkaline metal sodium and inorganic metavanadic acid. From water solutions crystallizes as dihydrate.

Minerals

Occurs in nature as munirite and metamunirite minerals.

Precursors

Reaction between sodium hydroxide and vanadium pentaoxide

Chemical equation:

2NaOH + V2O5 = 2NaVO3 + H2O


For preparation of 100.00g of sodium metavanadate dihydrate а 57.57g of vanadium pentaoxide and 25.32g of sodium hydroxide is required.

Add to flask with hot concentrated solution of hydroxide sodium small amount of vanadium pentaoxide with intense stirring. Heat it to 100°C for few minutes for reaction completion and then filter out. For purifying compound from hydroxide add large amount of cold ethanol, acetone or toluene to solution, salt will settle to the bottom in the form of fine crystals or powder. Filter precipitate and wash it with small amount of the same solvent, then filter the solution and use it for crystal growing.

Reaction between sodium hydroxide and ammonium metavanadate

Chemical equation:

NaOH + NH4VO3 = NaVO3 + H2O + NH3


For preparation of 100.00g of sodium metavanadate dihydrate а 74.06g of ammonium metavanadate and 25.32g of sodium hydroxide is required.

Add to the flask saturated solution of sodium hydroxide and then add small parts of hot ammonium metavanadate solution with heating and stirring. Emission of large amount of ammonia will begin.Attention, exuding ammonia irritates eyes and lungs! The synthesis should be carried out only in a fume hood or outdoors!

Notes

There are some redox processes occurring in solution, because of them the crystal surface could be slightly yellow.

Storage conditions

Store in its original form or under several layers of varnish at average humidity and room temperature. Do not store in matchboxes or cotton wool and do not heat.

Solubility

Temperatureгр/100,00 гр water
(anhydrous)(dihydrate)
20°C293.15 K <br />68 °F <br />527.67 °R <br />19.3~26.5
25°C298.15 K <br />77 °F <br />536.67 °R <br />21.1~29.2
30°C303.15 K <br />86 °F <br />545.67 °R <br />~23.1~32.3
40°C313.15 K <br />104 °F <br />563.67 °R <br />~27.0~38.4
50°C323.15 K <br />122 °F <br />581.67 °R <br />~30.9~44.5
60°C333.15 K <br />140 °F <br />599.67 °R <br />~34.9~50.7
70°C343.15 K <br />158 °F <br />617.67 °R <br />38.8~56.8
80°C353.15 K <br />176 °F <br />635.67 °R <br />40.8~60.1
Insoluble in ethanol, methanol, acetone, toluene and isopropanol.


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