This might give you some leads:  http://vanadium.atomistry.com/metavanadates.html

Thanks, I've seen that site before. One of the issues is the possible vanadium speciation in aq. samples. Depending on concentration and exact pH, there are several possible species present. 

I imagine a procedure would call for dissolving V2O5 in KOH solution, but I need to know the concentrations used to prepare the KVO3 in solution, and the procedure for isolating it (either crashing it out by adding an alcohol, evaporation, or common ion such as KCl). Sometimes the hardest procedures to find are the ones that were done >50 years ago. 

I found a procedure from Inorganic Syntheses vol 15 using V2O5 and K2CO3. I will try it, but if anyone has any other references, I'd appreciate them!

Dear Efram:

Do you have any especial interest in synthesizing KVO3? If not, I think is better if you acquire it commercially. It is not too expensive. See for example: 431052 Aldrich Potassium metavanadate (http://www.sigmaaldrich.com/catalog/product/aldrich/431052?lang=es®ion=MX)

Best regards:

Aaron

Our funds are maxed out for this project, so relatively speaking 88$ would be considered too expensive. Thanks though. If I could source ~25 g for under 30$ I would purchase commercially. I tried the inorganic syntheses method yesterday at half scale. Link is here:

https://books.google.com/books?id=N_qYz6_O_i8C&pg=PA104&lpg=PA104&dq=potassium+metavanadate+potassium+carbonate&source=bl&ots=8LnS7mUJ33&sig=CMNL55ybERCESEbmrt0XveZ9fHk&hl=en&sa=X&ved=0ahUKEwjVkP7Gy8bOAhUEKh4KHZ7UDhEQ6AEISDAH#v=onepage&q=potassium%20metavanadate%20potassium%20carbonate&f=false

After adding 5 mL of 3% H2O2 in the above procedure, I had the dark-tanbrown mixture they describe. Something came up and I had to deviate from the above procedure, I left it stirring/evaporating at 70 C for 5 h, the procedure calls for 90C for 2.5 h. 

When I returned, I had a yellow supernatant and a pink/peach solid with the volume reduced to 75 mL. Very different than the black/brown mixture I was supposed to have with light yellow filtrate. Not sure what the peach/pink solid is. Not very soluble in water, goes into KOH solution, turns red in 1M HCl. I will try 51V NMR, but I think the reaction cant be salvaged. I might give the procedure one more shot on a day where I can definitely dedicate uninterrupted lab time towards the procedure, as I think I left it for too long. 

Dear Efram:

You must be cautious with the use of KOH/HCl or any other pair of substance which change the pH of your mixture because acid media induces the formation of decavanadate (V10O28)6- (orange to red aqueous solution). Thus, you probably will obtain crystals of potassium decavanadate.

Aaron,

The KOH/HCl I used was trying to determine the solubility of the pink solid I obtained by by heating the reaction too long by mistake. The dependence of vanadate species on pH is why I was asking for a reliable method for the synthesis of KVO3. If you know of a reliable synthesis starting from V2O5, please let me know, I am hesitant to attempt the Inorganic Syntheses method again due to their footnote stating the likely contamination of their product with decavanadate. Thanks!