Potassium metavanadate

Potassium metavanadate
Names:	potassium metavanadate potassium vanadate potassium trioxovanadate vanadum-potassium trioxide
Formula:	KVO3 (anhydrous) KVO3 · H2O (monohydrate)
Molar mass:	138.037 g/mol (anhydrous) 156.052 g/mol (monohydrate)
Density:	2.84 g/cm3 (anhydrous)
Crystal system:	orthorhombic (anhydrous) a=5.78 Å, b=10.794 Å, c=5.176 Åα=90°, β=90°, γ=90° orthorhombic (monohydrate) a=8.15 Å, b=13.58 Å, c=3.96 Åα=90°, β=90°, γ=90°
Shapes:	https://en.crystalls.info/w/uploads/media/f/fc/Spherolit.json Spherolit https://en.crystalls.info/w/uploads/media/5/52/Needle.json Needle
Color:	colorless pale yellow surface
Melting point:	528 °C801.15 K <br />982.4 °F <br />1,442.07 °R <br /> (anhydrous)
Magnetic properties:	diamagnetic
Stability:	stable (monohydrate) slightly hygroscopic (anhydrous)
Hardness:	fragile
Toxicity:	highly toxic LD50~100mg/kg

Description

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

Precursors

Reaction between potassium hydroxide and vanadium pentaoxide

Chemical equation:

2KOH + V₂O₅ = 2KVO₃ + H₂O

For preparation of 100.00g of potassium metavanadate monohydrate

monohydrate

anhydrous

а 58.28g of vanadium pentaoxide and 35.95g of potassium hydroxide is required.

Add to flask with hot concentrated solution of hydroxide potassium 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 potassium hydroxide and ammonium metavanadate

Chemical equation:

KOH + NH₄VO₃ = KVO₃ + H₂O + NH₃↑

For preparation of 100.00g of potassium metavanadate monohydrate

monohydrate

anhydrous

а 74.96g of ammonium metavanadate and 35.95g of potassium hydroxide is required.

Add to the flask saturated solution of potassium 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

Keep in its original form or under several layers of varnish at average humidity and room temperature. Do not keep crystals near heaters.

Solubility

TableGraph

Temperature	g/100,00 g water
	(anhydrous)	(monohydrate)
0°C273.15 K <br />32 °F <br />491.67 °R <br />	1.4	~1.6
25°C298.15 K <br />77 °F <br />536.67 °R <br />	10.7	~12.3

Insoluble in ethanol, methanol, acetone, toluene and isopropanol.

Gallery

• 

  Potassium metavanadateVladimir Semikin, VKontakteVladimir SemikinVKontakte

Sources

• R.A.Kiper Properties of compounds. Handbook
• C.Christ, The crystal structure of potassium metavanadate monohydrate

Navigation

Potassium compounds
Salts	Potassium bromate (KBrO3) • Potassium bromide (KBr) • Potassium chlorate (KClO3) • Potassium chloride (KCl) • Potassium chromate (K2CrO4) • Potassium dihydrophosphate (KH2PO4) • Potassium dichromate (K2Cr2O7) • Potassium iodide (KI) • Potassium hydrofluoride (KHF2) • Potassium hydrophosphate (K2HPO4) • Potassium hydrophthalate (KC8H6O4) • Potassium metavanadate (KVO3) • Potassium nitrate (KNO3) • Potassium sulfate (K2SO4) • Potassium thiocyanate (KNCS)
Double salts	Aluminum-potassium sulfate (KAl(SO4)2) • Antimony(III)-potassium tartrate (K2Sb2(C4H2O6)2) • Chromium(III)-potassium sulfate (KCr(SO4)2) • Cobalt(II)-potassium sulfate (K2Co(SO4)2) • Copper(II)-potassium sulfate (K2Cu(SO4)2) • Indium(III)-potassium sulfate (KIn(SO4)2) • Iron(II)-potassium sulfate (K2Fe(SO4)2) • Iron(III)-potassium sulfate (KFe(SO4)2) • Lithium-potassium sulfate (KLiSO4) • Magnesium-potassium sulfate (K2Mg(SO4)2) • Magnesium-potassium sulfate-chromate (K2CrO4 · MgSO4) • Manganese(II)-potassium sulfate (K2Mn(SO4)2) • Nickel-potassium sulfate (K2Ni(SO4)2) • Potassium-sodium tartrate (KNaC4H4O6) • Vanadium(III)-ammonium sulfate (NH4V(SO4)2) • Zinc-potassium sulfate (K2Zn(SO4)2)
Complexes	Potassium dioxalatocuprate(II) (K2[Cu(C2O4)2]) • Potassium hexanitrocobaltate(III) (K3[Co(NO2)6]) • Potassium hexachlororhodiate(III) (K3[RhCl6]) • Potassium hexacyanocobaltate(III) (K3[Co(CN)6]) • Potassium hexacyanoferrate(II) (K4[Fe(CN)6]) • Tripotassium-sodium hexacyanoferrate(II) (K3Na[Fe(CN)6]) • Potassium hexacyanoferrate(III) (K3[Fe(CN)6]) • Potassium hexacyanochromate(III) (K3[Co(CN)6]) • Potassium tetraiodobismuthate (К[BiI4]) • Potassium tetraiodomercurate(II) (K2[HgI4]) • Potassium trioxalatoaluminate (K3[Al(C2O4)3]) • Potassium trioxalatocobaltate(III) (K3[Co(C2O4)3]) Potassium trioxalatoferrate(III) (K3[Fe(C2O4)3]) • Potassium-sodium trioxalatoferrate(III) (K5Na[Fe(C2O4)3]2) • Dipotassium-sodium trioxalatoferrate(III) (K2Na[Fe(C2O4)3]) • Potassium trioxalatochromate(III) (K3[Cr(C2O4)3])