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Sodium metavanadate | |
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Names: | sodium metavanadate sodium vanadate sodium trioxovanadate vanadum-sodium trioxide |
Formula: | NaVO3 (anhydrous) NaVO3 · 2H2O (dihydrate) |
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: |
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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:
100.00
g of sodium metavanadate dihydrate
а 57.57
g of vanadium pentaoxide and 25.32
g 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:
100.00
g of sodium metavanadate dihydrate
а 74.06
g of ammonium metavanadate and 25.32
g 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
Temperature | гр/100,00 гр water | |
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(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 |
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 |
Gallery
Video
Sources
Vanadates | |
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Potassium metavanadate (KVO3) • Sodium decavanadate (Na6V10O28) • Sodium metavanadate (NaVO3) |