Sciencemadness Discussion Board

Strange Vanadium Compound?

elementcollector1 - 4-7-2015 at 10:49

I recently prepared for a vanadium thermite by drying and calcining some vanadium oxide I had (I'd attempted to dissolve it in acid, with mixed results, and wanted to save the undissolved solid). However, to my surprise, the vanadium pentoxide melted on contact with a blowtorch to a silicon-esque, dark metallic blue substance. I don't think this is a different oxide of vanadium, given that all the oxides I've looked up have melting points close to 2000 C, but what else could it be?

deltaH - 4-7-2015 at 11:06

I'd hazard a guess a hydrate of an oxide? A little more info would be helpful...

elementcollector1 - 4-7-2015 at 11:44

Not sure what else I can give you. The crucible was stainless steel, the torch ran on propane, and the strange new compound remained liquid at red heat whenever the torch was on it. It also fluxed to the walls, melting off the sides of the crucible.

Apparently, vanadium oxide hydrate does exist - but nobody seems to tell me what color it is.

deltaH - 4-7-2015 at 21:22

The extra info request was for your source of the vanadium pentoxide ;)

kecskesajt - 5-7-2015 at 00:21

IIRC the vanadium pentoxide has a melting point of 700 C° and decomposes at 1600 C°.It could be a lower oxide of Vanadium.

chornedsnorkack - 6-7-2015 at 13:17

Yes, the simple oxides are high-melting:
V2O5 690 degrees, yellow
VO2 1967 degrees, deep blue

But there are also phases between VO2 and V2O5, like V3O7, V4O9 and V6O13. Plus there is possibility for eutectic liquids.

Which colour dominates in molten solutions of VO2 in V2O5 - the yellow of V2O5 or the blue of VO2?

SimpleChemist-238 - 7-7-2015 at 11:22

I would like to do some vanadium chemistry some time in the future but I just got some oxalic acid and iron oxide to play with along with a half kilo of sulfur! My fourth of July was the best in the all of Florida! I made smoke bombs with KMnO4 and used M-80s to set them off.