At 11:23 11/08/2001, Lachlan Cranswick wrote: >A list of canned programs for doing bond-valence calculations follows. >(Any additions/corrections appreciated): ICSD-for-WWW http://barns.ill.fr/dif/icsd/ also calculates bond valence sums when you ask for the structure to be drawn. See: http://barns.ill.fr/dif/icsd/icsd_bonds.html#Bonds In fact the calculation is trivial if you have a list of all the bond lengths and the table of empirical parameters for the various ion-pairs. Be a little careful in interpreting the bond valence sums, as David Brown himself points out in: J.Solid State Chem. 82, 122. "Valence sum rule calculations for YBa2Cu3O7." This paper may be a little too pessimistic :-) but it is true that ions in general must occupy positions that may not be the ideal size. Be particularly careful with calculations at higher temperatures. Incidentally, these bond valence ideas were originally by Pauling and Zachariasen. Alan. Dr Alan W. Hewat, Diffraction Group Leader. Institut Laue-Langevin, BP 156X Grenoble FRANCE 38042 fax (33)4.76.20.76.48 tel (33) 4.76.20.72.13 (or .26) <[EMAIL PROTECTED]> http://www.ill.fr/dif/AlanHewat.htm
