I am planning on making cerium nanoparticles and currently at the resource acquisition phase of the endeavor. I am seeing that there is anhydrous, hydrate, dihydrate, and tetrahydrate salts available. I was thinking that what I should be getting is the anhydrous, in order to maintain a proper stoichiometry with the stabilizer I am using to carry out the oxide formation at a raised pH--however, I'm realizing now that it would be easy to account for the hydrates in the salt and thus not a real problem.
What that leaves me with is a question of what the best one to go with would be--I would assume I should go for the one that is most easily purified, as I am trying to make this a food-grade synthesis and I want to minimize the trace metals in the final product. Are the hydrates more easily purified than the anhydrous? Trying to also conserve funds, which I assume would accord with the most easily purified form of the compound.