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/ _____________________________________________________________
