[sdpd] Li3RuO4

[Armel Le Bail <armel... @fluo.univ-lemans.fr>]

So, in fact, the Li3RuO4 structure was predicted in the P1
space group (programs GASPP + GULP), once TREOR gave 
a monoclinic cell proposition. The final space group (P2/a)
was deduced from the structure proposition, and the structure
refinement was done by GSAS.

Thus, the prediction (genetic algorithm) was not made by using
a cost function involving the powder pattern.

It may be considered as strange that Li3RuO4 with 6 
independent atoms in P2/a is qualified of "complex"
in 1995, just after the structure of La3Ti5Al15O37 with
60 independent atoms is determined by classical powder 
methodology (structure factors extraction, direct method).
See :   J. Solid State Chem. 111 (1994) 52-57.

But of course, for a purely predictive attemp, it was
really complex. Moreover, it is still probably out
of the current true prediction possibilities (without
the cell knowledge).

IMHO, Li3RuO4 would not have resisted more than 30 sec.
to such a classical analysis. Even a Patterson would have
revealed instantly the Ru position.

Anyway, is ENDEAVOUR able to guess the Li3RuO4 
structure ?

I tested ESPOIR on that problem with 100% success
rate whatever the space group (P1 with 16 atoms, P-1
with 8 atoms, or P2/a with 6 atoms).

Best,


Armel Le Bail - Universite du Maine, Laboratoire des Fluorures,
CNRS ESA 6010, Av. O. Messiaen, 72085 Le Mans Cedex 9, France
http://www.cristal.org/