>
> Hi Folks,
>
> The DuPont Powder Challenge has been Won... See :
> http://www.pitt.edu/~geib/powderresults.html
>
> The formula which was given as "HAlF4" is now PyH(Al3F10).
> Never trust DuPont crystallographers (which in turn have now
> stopped to trust their chemists ;-).
>
> That job would certainly merit more than 1000 US$ !
> Congratulations to the winners, and happy new year to all.
If not too rude a question - how good were
the structures derived from the "false"
chemical information (taken on good
faith as being correct)?
Fit, bond lengths and angles? Only
a cursory comment is made about the
alternatives solutions that were submitted.
While single crystal has the reputation of being
able to correct the synthetic chemist - what does
this imply for solving structures from Powders?
---
Jumping to conclusions with near zilch hard
information. The solution/refinement sequence is
not described but the webpage mentions co-ordinates
being refined using GSAS. GSAS also
has convenient fourier electron density map
generation and viewing. What is the corellation in
the "goodness" of the "submitted" structure vs the
refinement software's ability to conveniently generate
and view fourier maps ? Especially with poor quality
XRD data. Wouldn't refining without the routine aid
of Fourier maps be like flying blind to some extent?
Or is examining electron density space considered
irrelevant in modern structure solution/refinement
from powder data?
----
Additions/corrections welcome; but out of the dozen or
more available Rietveld packages, there are only 3(?)
which allow convenient fourier contour map generation
and viewing(?):
GSAS - UNIX/DOS(Windows):
ftp://mist.lansce.lanl.gov
http://www.ccp14.ac.uk/ccp/ccp14/ftp-mirror/gsas/
LHPM/Rietica for Windows:
ftp://ftp.ansto.gov.au/pub/physics/neutron/rietveld/Rietica_LHPM95/
http://www.ccp14.ac.uk/ccp/ccp14/ftp-mirror/ansto/pub/physics/neutron/rietveld/Rietica_LHPM95/
Runthrough:
http://www.ccp14.ac.uk/tutorial/lhpm-rietica/demo.htm
EXPO - Sirware (VMS/UNIX/Windows):
http://www.ba.cnr.it/IRMEC/SirWare_main.html
http://www.ccp14.ac.uk/ccp/web-mirrors/sirware/IRMEC/SirWare_main.html
This rises to 4 if the LHPM/Riet7 software with FORDAP/CSRIET for
Windows interface software is included - which is not presently
available via the internet.
Lachlan.
--
Lachlan M. D. Cranswick
Collaborative Computational Project No 14 (CCP14)
for Single Crystal and Powder Diffraction
Daresbury Laboratory, Warrington, WA4 4AD U.K
Tel: +44-1925-603703 Fax: +44-1925-603124
E-mail: [EMAIL PROTECTED] Ext: 3703 Room C14
NEW CCP14 Web Domain (Under heavy construction):
http://www.ccp14.ac.uk
