ICDD PDF-4+ 2012 Instructions

CuOx–TiO2–Nb2O5 pseudoternary phase diagram”, Journal of Solid State Chemistry, 2011 for
further details of this study).
The rutile peaks are also present in the other two histograms, for x = 0.242 and 0.286;
however, they are no longer shifting with composition. In addition, we also see extra
reflections – most notably at around 24 and 30 º2θ. In combination, these data show that
the limit for solid solution formation (in samples prepared at 935 ºC as these were, at least)
lies between x = 0.20 and x = 0.242; in this example, I will work on the data for x = 0.286, to
make the presence of the secondary phases obvious.
The indexing of these Bragg reflections from secondary phases was initially informed by the
pseudoternary phase diagram, on which I was working. Previously reported phases with
compositions closest to those of my two rogue samples were obvious candidates to check
first – there were a number of copper niobate and titanium niobate phases listed in the
Powder Diffraction File.
Loading my data file in to SIeve+, I based my initial search filter on what I suspected from
where the composition lay in the pseudoternary phase diagram; I was expecting to see
phases that definitely contained Cu, Nb and O, and might also contain Ti. This returned 24
cards. The software immediately identified a monoclinic CuNb2O6 phase, which gave a good
match for many of my observed reflections. After accepting this card (04-­‐014-­‐9621), the
software pulled up a second, orthorhombic polymorph of CuNb2O6 – this was anticipated,
from literature reviews, as these two phases always co-­‐exist. I accepted this card by again
clicking the handshake button.
No further results were returned. However, there were still additional unindexed
reflections in my data. From my other studies, I knew from the pattern that this was my
doped rutile phase – only one such phase was listed in the database, ‘Cu0.5Ti0.5NbO4’ (x =
0.20) in PDF card number 00-­‐046-­‐0524. In the SIeve+ window, I went into the ‘Matches’
menu, and chose ‘Add PDF #...’, and entered this card manually. The peaks appeared, and
are a little way off mine – this is to be expected, since the rutile phase in my specimen has a