% IMPORTANT: The following is UTF-8 encoded. This means that in the presence % of non-ASCII characters, it will not work with BibTeX 0.99 or older. % Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or % “biber”. @ARTICLE{Birnbaum:56074, author = {Birnbaum, U. and Hake, J.-F. and Linssen, J. and Walbeck, M.}, title = {{T}he hydrogen economy: technology, logistics and economics}, journal = {Energy materials}, volume = {1}, issn = {1748-9237}, address = {London}, publisher = {Maney}, reportid = {PreJuSER-56074}, pages = {152 - 157}, year = {2006}, note = {Record converted from VDB: 12.11.2012}, abstract = {The synthetic vanadinites (Pb(x)Ca(10-x))(VO4)6F2delta, 1 < x < 9, adopt a P6(3)/m apatite structure with 9.7590 (1) < or = a < or = 10.1179 (1) A and 7.0434 (3) < or = c < or = 7.4021 (1) A. The partitioning of calcium and lead over the AI(4f) and AII(6h) positions is nonstoichiometric with lead preferentially entering the larger AII site. High-resolution electron microscopy showed that samples annealed for 10 h at 1073 K are in disequilibrium with calcium- and lead-rich microdomains co-existing at unit-cell scales. For (Pb5Ca5)(VO4)6F2delta, sintering in excess of 2 weeks is required for the metals to order macroscopically. As annealing progresses, c/a, the partitioning coefficient kPb(AI/AII) and the AIO6 metaprism twist angle (phi) adjust cooperatively to enlarge the apatite channel, and thereby accommodate higher lead content. These results demonstrate that phi is a sensitive measure of disequilibrium and a useful device for monitoring changes in apatite topology as a function of composition.}, cin = {STE}, ddc = {620}, cid = {I:(DE-Juel1)VDB64}, pnm = {Nachhaltige Entwicklung und Technik}, pid = {G:(DE-Juel1)FUEK408}, typ = {PUB:(DE-HGF)16}, pubmed = {pmid:15017085}, doi = {10.1179/174892406X177266}, url = {https://juser.fz-juelich.de/record/56074}, }