Dear Clemente, Bruce and others, Interesting to hear about these window problems. But another factor may give you some more teething pains - the use of ClF3 as fluorination agent in a laser system. ClF3 decomposes by irradiation of the laser wavelength and gives you a relatively large quatity of F2 with your O2 after freezing the other products by liq-N2. I think best fluorination agent is F2 with the Asprey salt (as Bruce mentions to use), and alternatively also BrF5, which is more stable, can be used - there the problems are rather where to get it (China?) and safity regulations (I wonder if F2 is not giving similar problems for safity regulations?). Can anyone comment on this fact of decomposing ClF3 in laser systems? I remember once I heard Chris Harris at UCT had terrible problems with ClF3 - is that true and can you tell more about it Chris? Best wishes, Pier de Groot. -- ************************************************************** Dr. P.A. de Groot University of the Witwatersrand Economic Geology Research Unit Department of Geology Private Bag 3 2050 Johannesburg South Africa Tel. +27 11 7162564 Fax. +27 11 3391697 E-mail <[log in to unmask]> Visit the combined HOME-PAGE of EGRU-Geology on the Internet: http://www.wits.ac.za/science/geology/index.htm **************************************************************