I need the cif diffraction data file for Nb2O5. The specification for this compound are given below:
Chemical Name: Nb2O5
Crystal Structure: psudo-hexagonal
a:3.607 b :3.607 c:3.925
I cannot find the cif file from Findit or ICSD. I would be really grateful if anyone share it.
Thanks a lot.
A few things to think about:
-databases are there to help us to find our way through original literature. Further, no database completely covers all literature. So not all known crystallographic information is in the ICSD. Maybe some quite classical literature search (including forward/backwards citation may help) instead of looking only into a database.
-You ask for pseudohexagonal Nb2O5. To get it a bit philosophical: there is no such thing like pseudohexagonal Nb2O5, but there is something which somebody has called pseudohexagonal Nb2O5. So the starting point must be the source where somebody has called some material based on some experimental evidence pseudohexagonal Nb2O5. Apparently that person has not given more crystallographic details than the lattice parameters, but apparently there have been reasons to call it "pseudo"hexagonal. That usually implies pseudosymmetry, i.e. having some description of an averaged structure. In fact the unit cell is very small.
-based on a simple volumetric estimate, there should be 1/2 formula unit Nb2O5 in your hexagonal unit cell, i.e. NbO2.5. Hence the diffraction pattern will be dominated (likely) by a primitive arrangement of Nb atoms, yielding a simple diffraction pattern (if Nb itself is not disordered)
-go through the real reported structure models and try to find out whether any of these gives a diffraction pattern implying strong reflections agreeing with the diffraction pattern predicted by the simple model.
Dear Qing Ji,
the so called pseudo-hexagonal phase of Nb2O5 is related do the temperature treatment of the oxide synthesis. The synthesis obtained at 450 C/1hour give rise to a such called TT phase of Nb2O5 (JCPDS 00-028-0317). Its is followed by an endothermic event at about 425 C (TG and DSC).
Whatever it is called, that is the reference of the so called TT phase of Nb2O5.
Best regards,
WNM
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