Standards for EPMA-Vanadium

[crystalgrower]

I would like to see somebody with access to hydrothermal equipment to grow two V materials to be used as  standards for microanalysis  (SfM hereafter).

First of all YVO4 which  would serve as a general material and for EDS. YPO4 and other Y-P-O compounds all suffer from overlap of the Y and P.  The yellow to brown material available on ebay is not stoichiometric but it has been found to be the ideal starting material for perfect crystals as shown in detail by  A. R. Forbes et al,  Journal of Crystal Growth (2008) vol 310 pp 4472-4476
I had no luck getting a response from the corresponding author ( J Kolis) a year ago. 

Second, some AlV3O9 because analyses of metavanadates  (hydrated minerals containing the unique unit V10O28) are presently using V metal to calibrate.  So the hydrothermal synthesis has been published for LaV3O9 in sufficient detail to be a good starting point: Y. Oka et al, Journal of Solid State Chemistry  (2000) v 152 pp 486-491

I don’t know if a crucible or sealed-tube furnace synthesis of Al2O3 and V2O5 would succeed.  Sc2O3 + P2O5 gives isostructural ScP3O9 from Sc:10P mix in open Pt crucible at 500°C.  ScV3O9 is just a hair too low in V to be the ideal SfM.

I have done some searching and I would not try to make a hydrated metavanadate for SfM.  There are good discussions of the pH control of self-assembly of V-O phases in journal of structural inorganic chemistry. 

[aburnham]

YVO4 can be grown in a box furnace using V2O5 as the flux. The V2O5 can be dissolved away afterwards. I have successfully grown ScVO4  this way. Tields lots of ~ 1 mm grains, mostly lacking melt inclusions.