Sodium decavanadate

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  Sodium decavanadate   
Names: sodium decavanadate

Formula: Na6V10O28 (anhydrous)
Na6V10O28 · 18H2O (octadecahydrate)
SMILES: [O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[Na+].[Na+].[Na+].[Na+].[Na+].[Na+].[V].[V].[V].[V].[V].[V].[V].[V].[V].[V]
Molar mass: 1095.332 g/mol (anhydrous)
1419.600 g/mol (octadecahydrate)
Density: 2.42 g/cm3 (octadecahydrate)
Crystal system: triclinic (octadecahydrate)
Shapes:
https://media.crystalls.info/w/uploads/media/Beveled_rhombic_prism.json
https://media.crystalls.info/w/uploads/media/Deformed_tetragonal_bipyramid.json

Color: bright red
Decomposition point: ~50 °C
323.15 K
122 °F
581.67 °R
(octadecahydrate)
Magnetic properties: diamagnetic
Stability: rapidly erodes (octadecahydrate)
Hardness: relatively strong
Toxicity: poisonous

Description

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

Precursors

Reaction between sodium metavanadate and diluted acetic or sulfuric acid

Chemical equation:

10NaVO3 + 4CH3COOH = Na6V10O28 + 4CH3COONa + 2H2O
10NaVO3 + 12H2SO4 = Na6V10O28 + 12Na2SO4 + 12H2O

For preparation of 100.00g of sodium decavanadate octadecahydrate а 111.27g of sodium metavanadate dihydrate and 224.07g of 37% sulfuric or 24.17g of 70% acetic acid is required.
Add hot acid to the flask, then add small parts of sodium compound with stirring until heating will stop (attention, the solution may boil!) . For purifying compound from unreacted substances 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.

Influence of pH level

It is optimal to grow crystals at 4..7 pH level. At higher levels there are such byproducts as hexavanadate or metavanadate.

Storage conditions

For crystal storing use hermetic vessel with small amount of saturated solution at the bottom or place wadding moistened with such solution. You can use such alternatives as vessel with vaseline or vegetable oil, organic non-hygroscopic solvent (kerosene, benzine or paraffin). Also you can use acrylate polymer or another kinds of solidifying plastic.

Solubility

Temperatureгр/100,00 гр water
(anhydrous)(octadecahydrate)
30°C
303.15 K
86 °F
545.67 °R
~23.2
23.2 g/100g
18.831 %
~32.33
32.33 g/100g
24.431 %
Insoluble in ethanol, methanol, acetone, toluene and isopropanol.

Gallery


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