Doug (and others),

I tried a number of years ago to fluorinate a simple sulfate using F2. That was before I had a morning cup of coffee and I realized that the reason that it will not work is that oxygen is too close to fluorine on the emf scale and competes, forming SOF compounds. Predictably, this might be ameliorated with higher F2 pressures, but I did not test it sufficiently to find a way around this problem. Fluorination (using F2) of sulfides in the presence of silicate-derived O2 (up to a point) works (which permits very good in situ analyses), but sulfates are another matter. I can imagine that the situation with BrF5 is even worse when you consider the other product compounds possible.

Bruce
Bruce E. Taylor, Ph.D.
Geological Survey of Canada
601 Booth Street
Ottawa, Ontario   CANADA   K1A 0E8

Tel:  613-995-4673 (office); 613-992-4046 (lab)
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> ----------
> From: 	Stable Isotope Geochemistry on behalf of Doug Crowe
> Reply To: 	Stable Isotope Geochemistry
> Sent: 	Monday, May 22, 2006 9:56 AM
> To: 	[log in to unmask]
> Subject: 	laser ablation for sulfate O
> 
> All-
> 
>      I am curious as to the number (if any) of folks who have tried to do laser ablation with BrF5 for 
> oxygen isotope analysis of sulfate minerals as well as hydroxylated sulfur/sulfate species.  I would 
> like to analyze alunite, and would like to hear from anyone who has gone down this road.  Also, I 
> am pondering the wisdom of doing clay minerals by laser with BrF5, and recall several 
> conversations with others who were attempting this.  We have an airlock design similar to John 
> Valley's/Mike Spicuzza's in Madison, but I would like to know if the spattering issues during 
> heating have been solved.
> 
> Dr. Doug Crowe
> Department of Geology
> University of Georgia
> Athens, GA  30602  USA
> [log in to unmask]
>