Much less than triclinic..aperiodic! Norberto Inviata dal mio Windows Phone ________________________________ Da: Davide Levy<mailto:[email protected]> Inviato: 10/05/2015 11.13 A: 'Alan Hewat'<mailto:[email protected]>; 'Leonid Solovyov'<mailto:[email protected]> Cc: 'Lista Rietveld'<mailto:[email protected]> Oggetto: RE: On the “crystallographic good practices”
I am glad not to be the only one who think that all crystal are triclinic :) . Are you interested for a Rietveld Method group on Facebook ? Davide From: [email protected] [mailto:[email protected]] On Behalf Of Alan Hewat Sent: 10 May, 2015 11:33 AM To: Leonid Solovyov Cc: Lista Rietveld Subject: Re: On the “crystallographic good practices” Dear Leonid. You have a point, but they also have other evidence for lower symmetry. (Personally I have for long believed, secretly, that all structures were at best triclinic, and that everything else was just an average :-) I know you like to be provocative, but let's not start a little war over this. Normally the referees and journals, together with the authors, are responsible for what they publish. Best wishes, Alan. On 9 May 2015 at 19:02, Leonid Solovyov <[email protected]<mailto:[email protected]>> wrote: Regarding the query of Leopoldo Suescun: ”Shouldn´t the IUCr take action and try to influence the journals that frequently publish x-ray data (as a complementary characterization technique but that determines the validity of other results) to have well-trained crystallographers review any article that contains x-ray diffraction data?” Unfortunately, the issue of crystallographic review is problematic even in the IUCr journals, especially for powder data. A fresh instance from Acta B: http://dx.doi.org/10.1107/S205252061500342X where the crystal structures of alpha-Fe2O3 and alpha-Cr2O3 are “re-refined” to be monoclinic. The monoclinic symmetry is “substantiated” by the observation of a “complex” peak broadening that, in fact, is well described by the anisotropic strain model available in all popular Rietveld programs. With such structure validation, all crystal structures may be re-refined, potentially, to lower symmetry, as the anisotropic strain broadening is a common powder pattern feature. If this practice is accepted in an IUCr journal, what can we expect from non-crystallographic literature? ******************************************************* Leonid A. Solovyov Institute of Chemistry and Chemical Technology 660036, Akademgorodok 50/24, Krasnoyarsk, Russia http://sites.google.com/site/solovyovleonid ******************************************************* ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Please do NOT attach files to the whole list <[email protected]<mailto:[email protected]>> Send commands to <[email protected]<mailto:[email protected]>> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/[email protected]/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -- ______________________________________________ Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE <[email protected]<mailto:[email protected]>> +33.476.98.41.68 http://www.NeutronOptics.com/hewat ______________________________________________
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Please do NOT attach files to the whole list <[email protected]> Send commands to <[email protected]> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/[email protected]/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
