>However, if you carefully read some of his recent papers, you may
>find the answer there (the paper on CeO2 by his group was published in Chem.
>Mater.; I don't have it handy but can find out the exact citation if
>needed).
I hope this was not exactly the same sample because a Round Robin
is supposed to be a blind test. There is one nanocrystalline CeO2 in
a recent paper from J.I. Langford, D. Louër and P. Scardi, J. Appl.
Cryst. 33 (2000) 964-974, but this is clearly not the same as the
Round Robin CeO2 sample (much broader lines). A series of 4
CeO2 samples annealed at selected temperatures between 230 and
960°C is discussed by D. Louër in the book "Defect and Microstructure
Analysis by Diffraction" edited by R.L. Snyder, J. Fiala and H.J. Bunge,
1999, 673-697 (IUCr/Oxford University Press). The <D> sizes
are between 41(1) and 859(14) Angstroms (<D>=147(1) Angstroms
for the sample annealed at 600°C). The original paper is N. Guillou,
J.P. Auffredic and D. Louër, Powder Diffraction 10 (1995) 236-240.
In my Round Robin contribution, I did not try to give <Da> (area weighted)
or <Dv> (volume weighted), I gave only the area-weighted Fourier mean
apparent size, say <M>, with the following relation if crystallites are
spheres : <Da> = 3 <M> / 2. I had no indications that the crystallites
could be spherical...
Let us hope that the Round Robin CeO2 sample was annealed at a
different temperature than in the previous studies, or had a
completely different origin.
Best,
Armel
