Yes, I saw the papers. There are two key restrictions given by authors for the desired structure:
- four oxygen layers with two middle ones having a substitutional barium and
- no m-plane perpendicular to c direction.
From this point none of the mentioned can suit me.
It is mentioned in several papers as 'early published'
To give an example: J.Phys.Chem, 1963, 67(4), 957 (member with index n=0)
http://pubs3.acs.org/acs/journals/toc.page? incoden=jpchax&indecade=3&involume=67&inissue=4
Meilleures salutations, Ivan
Le Jul 26, 2004, � 10:23, Alan Hewat a �crit :
structure of Ba2Fe8O14 with P-3m1 symmetry and c parameter about 9.6 A? It is mentioned in several papers as 'early published'
The best ICSD does is BaFe4O7 with P63/m and c parameter 13.8A ie ~sqrt(2) times your c-parameter.
Okamoto, S.;Okamoto, S.I.;Ito, T. The crystal structure of barium diferrite (1973)
�Acta Crystallographica B 29, 832-838 XRef�
There are many similar barium ferrites, often with P63/mmc symmetry, differing in how Fe is ordered in the pyramidal holes. A common feature appears to be a layer of pairs of FeO4 pyramids joined along c by a common corner and separated by 0,1,2... layers of edge connected pyramids eg starting with the simplest where Fe is again Fe+++
Meriani, S. Polymorphism of barium monoferrite, Ba Fe2 O4 Acta Crystallographica B (1972) 28, 1241-1243 XRef
But maybe you know all this... 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 Mme Guillermet) <[EMAIL PROTECTED]>� http://www.ill.fr/dif/AlanHewat.htm ___________________________________________________________
