So far as I know (I may be wrong :-) ordered atomic positions for the two requested compounds, with supposed formulae *Ba2TeO4 *and *Ba2TeO5*, have not been determined. The closest I found were as I wrote: *"Sr Te O6 and Ba Te O6 <https://www.researchgate.net/publication/244748863_Sr3TeO6_and_Ba3TeO6_Double_perovskites_with_pronounced_superstructures>" *and *"Sr Te O4 <http://scripts.iucr.org/cgi-bin/getarticleid?issn=0108-2701&volume=41&fpage=1558&details=yes>". *I understand that unit cells and space groups have been assigned, but that is not sufficient.
If I am wrong, and ordered structures with this stoichiometry have indeed been determined, I hope people who have access to the databases will confirm that these structures actually exist, to save Rachid time and money. Otherwise it is not permitted to share or promote commercial databases on the Rietveld list. Alan. On 14 June 2016 at 16:42, Miguel Delgado <migu...@ula.ve> wrote: > Dear All, > > For more information about the PDF-4+, feel free to visit the following > page: http://www.icdd.com/products/pdf4.htm > > Kind Regards, > > Miguel Delgado > > On 6/14/2016 4:16 AM, Matteo Leoni wrote: > > dear everybody, > > I think there is some misconception here. > > It is true that the PDF-4+ is a commercial database: this means that > sharing the information taken from the database (as recently done here) is > an explicit violation of copyrights of ICDD and the violator might be > legally prosecuted. When you use the database you save the time needed to > look through the literature for the same information, paying the rights to > the original owner and checking for errors in transcription and, sometimes, > interpretation. That's why (at least) you pay for it. > > However, please update your records. The PDF-4+ is not the PDF-2. The > PDF-4+ is a materials database that contains the "old" PDF-2 information, > but it contains also structural data for a large quantity of compounds as > well as properties and experimental patterns for several compounds. It > contains also most of the ICSD coordinates that have been however > thoroughly checked in house, quality marked, cross referenced and corrected > when needed. > > So if the material is inorganic and the structure is not in PDF-4+, it > usually means the structure is either very doubtful, too new or not yet > extracted from the literature. > In this particular case, as the chemistry and the space group are known, > it is also likely that the compounds are isostructural to others already > described in the literature > > Just notice that there are free alternatives to the commercial databases > (e.g. COD, RRUFF) that in some cases can provide useful information, but in > all cases the copyright warning exists > > Matteo (Chair of the BoD of the ICDD) > > > ----------------------------------------------------------------- > > Prof. Matteo Leoni, PhD > > DICAM - University of Trento > via Mesiano, 77 > 38123 Trento - Italy > > Tel +39 0461 282416 Fax +39 0461 282672 > > e-mail: matteo.le...@unitn.it > > ---------------------------------------------------------------- > > 2016-06-14 9:04 GMT+02:00 Alan Hewat <alan.he...@neutronoptics.com>: > >> maybe they are in PDF4. >>> >> >> PDF4 is a commercial database of d-spacings and unit cells derived from >> them. It does not normally contain atomic positions, and not all structures >> in PDF4 have been determined. ICSD does contain atomic positions if they >> have been determined. >> >> Both PDF4 and ICSD are copyright and must not be posted to this mailing >> list. As well, there is an explicit warning not to attach files to the >> mailing list. Anyone who does so risks exclusion. >> >> There are other free databases that may contain the information you >> require, but I doubt it. Try using Google Scholar to first determine if the >> structures have been published. If not, you will have to determine them >> yourself. It is not so difficult if you have good data and know the space >> group and lattice dimensions. >> >> Alan >> ______________________________________________ >> * Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE * >> <alan.he...@neutronoptics.com> <alan.he...@neutronoptics.com> >> +33.476.98.41.68 >> http://www.NeutronOptics.com/hewat >> ______________________________________________ >> >> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> Please do NOT attach files to the whole list >> <alan.he...@neutronoptics.com> <alan.he...@neutronoptics.com> >> Send commands to <lists...@ill.fr> eg: HELP as the subject with no body >> text >> The Rietveld_L list archive is on >> http://www.mail-archive.com/rietveld_l@ill.fr/ >> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> >> >> > > > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > Please do NOT attach files to the whole list <alan.he...@neutronoptics.com> > <alan.he...@neutronoptics.com> > Send commands to <lists...@ill.fr> <lists...@ill.fr> eg: HELP as the subject > with no body text > The Rietveld_L list archive is on > http://www.mail-archive.com/rietveld_l@ill.fr/ > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > > > > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > Please do NOT attach files to the whole list <alan.he...@neutronoptics.com > > > Send commands to <lists...@ill.fr> eg: HELP as the subject with no body > text > The Rietveld_L list archive is on > http://www.mail-archive.com/rietveld_l@ill.fr/ > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > > -- ______________________________________________ * Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE * <alan.he...@neutronoptics.com> +33.476.98.41.68 http://www.NeutronOptics.com/hewat ______________________________________________
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