Good work Armel. Yes, sharing of open databases is encouraged :-) But please don't attach files.
Alan _____________________________________________________ From my mobile telephone Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE <alan.he...@neutronoptics.com> +33.476.98.41.68 http://www.NeutronOptics.com/hewat _____________________________________________________ On 15 Jun 2016 15:57, "xtal" <x...@noos.fr> wrote: > At 17:21 14/06/2016 +0200, you wrote: > > 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. > > > Hi Alan, > > If I understand well, sharing or promoting open databases is permitted on > the Rietveld list... > > About Ba2TeO5, it is said that it is isomorphous with Ba2WO5 and Sr2WO5. > Ba2WO5 belongs to the K2VO2F3 structure type which is described in an > Acta Cryst B issue and available as an entry in the Crystallography Open > Database : > http://www.crystallography.net/cod/2020524.html > > It is orthorhombic pseudo-tetragonal with 2b~c > Ba2TeO5 was originally indexed as tetragonal or possibly orthorhombic. > > So, here are very probably starting atomic positions for Ba2TeO5 ;-) > > Best, > Armel > -- ______________________________________________ * Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE * <alan.he...@neutronoptics.com> +33.476.98.41.68 http://www.NeutronOptics.com/hewat ______________________________________________
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