Thank you very much all of you.
From: Theodora Leventouri <[EMAIL PROTECTED]>
Reply-To: [email protected]
To: [email protected]
Subject: Re: Hydroxiapatite, carboapatite and fluorapatite - Request of
Date: Wed, 23 May 2007 11:59:12 -0400
Dear all,
Here are some papers on Rietveld refinement of neutron powder diffraction
patterns of natural, synthetic and substituted apatites:
1. "Neutron powder diffraction studies of silicon substituted
hydroxyapatite", Th. Leventouri, C. E. Bunaciu, V. Perdikatsis, J. Biomat.
24, 4205-11 (2003).
2. "A Comparison of Crystal Structure Parameters of Natural and Synthetic
Apatites from Neutron Powder Diffraction", Th. Leventouri, B. C.
Chakoumakos, N. Papanearchou, V. Perdikatsis, J. Mat. Res. 16, 2600-06
(2001).
3. "Powder neutron diffraction studies of a carbonate fluorapatite", Th.
Leventouri, B. C. Chakoumakos, H. Y. Moghaddam, V. Perdikatsis, J. Mat.
Res. 15, 511-7 (2000).
and a relevant:
Synthetic and Biological Hydroxyapatites: Crystal Structure Questions ",
Th. Leventouri, J. Biomat. 27, 3339-3342, (2006).
Try searching PubMed for materials such as apatites with
biological/medical interest eg
"Rietveld structure refinement of precipitated carbonate apatite using
neutron diffraction data".
Wilson RM, Elliott JC, Dowker SE, Smith RI. (2004) Biomaterials. 25(11),
2205-13.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&list_uids=14741636&dopt=Citation
According to the above, carbonate replaces some of the phosphate resulting
in average shrinking of these tetrahedra. They also located what might be
the water from their neutron refinement, which you won't see if you are
using X-rays :-)
Alan.
At 03:57 23/05/2007, Leandro Bravo wrote:
I´m refining a sample which contains a hydroxycarbofluorapatite (solid
solution). I´m refining it using CIF files from the ICSD, but it´s not
working so well, because they don´t have the file for the
hydroxycarbofluorapatite. So I´m using in the TOPAS the following files:
fluorapatite, carbofluorapatite, hydroxyfluorapatite and hydroxyapatite.
When using them the rwp is about 16 but when using only the
hydroxyapatite the rwp is 30. I´d would like to know if any of you have
very good quality STR files of hydroxyapatite, fluorapatite and
carboapatite, or only one file of hydroxycarbofluorapatite?!
_____________________________________________________________
Dr Alan Hewat, ILL Grenoble, FRANCE<[EMAIL PROTECTED]>fax+33.476.20.76.48
+33.476.20.72.13 (.26 Mme Guillermet) http://www.ill.fr/dif/people/hewat/
_____________________________________________________________
--
Dr. Theodora Leventouri
Professor of Physics
Physics Department, FAU
Boca Raton, FL 33431
Phone: 561-297-2695
Fax: 561-297-2662
_________________________________________________________________
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