Dear Kevin,
If your reaction between BrF5 and silicate mineral goes to completion (and I
hope it does) then you get fluorides: AlF3, NaF, CaF2, and other metals if
present as traces as fluorides, most of them as solids. SiF4 is in gaseous
form, but freezes well in the cold traps at liq-N2 temperature (If you are
interested in Si isotopes you can use this compound...). And of course, in
case of kaolinite you form HF gas (removed in cold traps too).
BrF5 gives restproducts such as BrF3 and Br (the brownish-red-orange
colours... as vapour or fluid (no solids) - and freezes in in the cold traps
too). This, of course, besides the gas of interest: O2.
Another solid product you find in your Ni reaction vessels is NiF2, and
eventually some NiO?!? - I have not seen any publication on this, but I
heard it was tested by someone sometime.... and NiO was found, causing some
memory or eventually isotopic fractionation. If anybody knows more about
this, or can inform me about any publication, report, personal experience,
etc., I like to hear about it.
All fluorides are hygroscopic and will form HF and metal oxides in contact
with water or water vapour. For that reason they are toxic and need to be
handled with care.
If you find other products, then something is wrong in your reaction (still
some silicate compounds available means incomplete reaction), or you did
introduce (for whatever reason) other material then the silicate mineral.
Probably a good deal you knew already, but maybe this is useful to others
too. Hope this includes what you wanted to know...
Best wishes,
Pier.
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Dr. Pier A. de Groot
Economic Geology Research Unit
University of the Witwatersrand
Private Bag 3
2050 Johannesburg
South Africa
Tel. +27 11 717 6582 Fax. +27 11 339 1697
E-mail: [log in to unmask]
WEB-site on "Handbook of Stable Isotope Analytical Techniques (2 volumes)":
http://www.icon.co.za/~pagroot/index.html, or if finding problems:
http://www.icon.co.za/~pagroot/index_1.html
last update: October 2, 2000
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