BaSiF6 or CaSiF6 structures
Did someone know the structure for one of these phases. I didn't find them on the ICSD but I notice that at http://fact.jst.go.jp/cr-vrml.html there is the BaSiF6 included. So it should be that someone has found the structure at least for this one. Thanks in advance, Luca Lutterotti ---Luca Lutterotti Dipartimento di Ingegneria dei Materiali, Universita' di Trento, via Mesiano 77, 38050 Trento, Italy e-mail address : [EMAIL PROTECTED] Home page : http://www.ing.unitn.it/~luttero Mirror: http://www.ccp14.ac.uk/ccp/web-mirrors/lutterotti/~luttero/ Phone number :+39-0461-88-2414 -Fax : +39-0461-88-1977-
weight fractions in GSAS .LST file
Hello, Firstly, thanks to those who answered my question about exchanging files between the UNIX & DOS versions of GSAS. Now I have more questions: How do I get GSAS to report weight fractions & their uncertainties in a .LST file? Having just completed some work on 4 samples I find that the wt fractions have been calculated from the scale factors for some samples but not others. Also, how can I get GSAS to provide estimated uncertainties in the wt fractions? (I am aware that a microabsorption correction is not included in GSAS). Thanks, Roger Mason
Re: BaSiF6 or CaSiF6 structures
Dear Luca: I checked the PDF and found entries cross-linked to the ICSD: 201510, 061273 for BaSiF6 Perhaps these will help. John At 07:50 PM 11/18/99 +0100, you wrote: >Did someone know the structure for one of these phases. >I didn't find them on the ICSD but I notice that at >http://fact.jst.go.jp/cr-vrml.html >there is the BaSiF6 included. >So it should be that someone has found the structure at least for this one. > > Thanks in advance, > > Luca Lutterotti > > > >---Luca Lutterotti > Dipartimento di Ingegneria dei Materiali, Universita' di Trento, > via Mesiano 77, 38050 Trento, Italy > > e-mail address : [EMAIL PROTECTED] > Home page : http://www.ing.unitn.it/~luttero > Mirror: http://www.ccp14.ac.uk/ccp/web-mirrors/lutterotti/~luttero/ > > Phone number :+39-0461-88-2414 >-Fax : +39-0461-88-1977- _ Dr. John Faber Principal Scientist ICDD 12 Campus Boulevard Newtown Square, PA, 19073 ph : (610)325-9814 fax: (610)325-9823 e-mail: [EMAIL PROTECTED] also see: http:\\www.icdd.com
New member of the rietveld e-list
Dear Rietveld-mailing list users, As I just subscribed this e-list, let me present myself: My name is Edouard RENY, and I'm a fresh doctor is material Science (I obtained my Doctor degree in France this february). Now I'm a post-doc in Japan working on silicon clathrate structures. the Rietveld refinement program I use is Fullprof (with a DBWD viewer), And I have a problem in refining the X-ray peak profiles of one of my samples: Whatever I do, the refinement leads always to Gaussian type profiles which we can see on the .prf file, at high 2 teta, don't match at all with the experimental profile. This sample contains some silicon, and there, no problem to refine the peak profiles (even if intensities are not perfect). However at low two tetas (for 2tetas < 50deg) , calculated peak shapes match quite well with experimental data. (see fig1.gif. At higher 2tetas, it's even worse) I use a PseudoVoigt, it leads usually to eta=0.35 (mixing parameter) approximatively. If I fix it to more lorentzienne values (0.6 or 0.8 for instance), residuals become too high. U,V, W combination refining converges but if we free eta, I always finish by having Gaussians peaks mixing the Ka1 and Ka2 contributions as one peak. What is strange is that there is no problem for the impurity silicon phase (peak shapes are well defined). The profile parameters of the two phases are not commonly refined. Has anyone been through this problem? has anyone have an idea of refinement procedures which would lead to a better peak profile refinement and avoid this false minimum where the program always seem to converge? Thanks in advance for your help Sincerely Edouard RENY
Re: BaSiF6 or CaSiF6 structures
At 19:50 18/11/1999 +0100, you wrote: >Did someone know the structure for one of these phases. >I didn't find them on the ICSD BaSiF6 is on ICSD-for-WWW at least. I couldn't draw the Svensson structure (low temperature data), but the Hoskins ambient structure looks OK. If you are looking at these materials, please measure at low temperatures (5K) - there may be a phase transition. +++ Svensson,G. Albertsson,J. Svensson,C. Elding,LI. (1986) Acta Chem.Scand.Ser.A 40 631-633 Crystal structure of BaSiF6 at 180K Hoskins,BF. Linden,A. Mulvaney,PC. O'Donnell,TA. (1984) Inorg.Chim.Acta 88 217-222 The structures of barium hexafluorosilicate and cesium hexafluororhenate(V) Babel,D. (1967) Journal of Inorganic and Nuclear Chemistry 3 1-87 Structural chemistry of octahedral fluorocomplexes of the transition elements Hoard,JL. Vincent,WB. (1940) J.Am.Chem.Soc. 62 3126-3129 Structures of Complex Fluorides. Barium Fluorosilicate and Barium Fluorogermanate +++ Alan Hewat, ILL Grenoble, FRANCE <[EMAIL PROTECTED]> tel (33) 4.76.20.72.13 ftp://ftp.ill.fr/pub/dif fax (33) 4.76.20.76.48 http://www.ill.fr/dif/
