Karl
For a good approximation of the [HF] in the soluble salts, use the dissociation equilibrium for HF which is driven by the [H+] and salt concentration. To one significant figure, the dissociation constant (Ka) for HF is 7E-4. Research using 19F NMR showed dissociated fluoride (likely F-H-F -) in several of the compounds you noted.
With regards,
Mike
Michael N. Cooper MS, MPH, CIH
Senior Managing Scientist
Exponent / Failure Analysis Associates
149 Commonwealth Drive
Menlo Park, California 94025
mcooper**At_Symbol_Here**exponent.com span>
cell (408) 313-2127
office (650) 688-1760
From:
DCHAS-L
Discussion
List [mailto:DCHAS-L**At_Symbol_Here**list.uvm.edu] On Behalf Of Alan Hall
Sent: Wednesday, April 07, 2010 11:30 AM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Subject: Re: [DCHAS-L] HF hazards
Karl,
At least the ammonium fluoride (I assume you mean ammonium bifouoride),
which
is used in a very dilute solution as a disinfectant in home/office
fish
tanks, has caused fatailties in children when a concentrated solution
has been
ingested. The poisoing seems to be the same as hydrogen
fluoride/hydrofluoric acid poisoning, and what data are
available
indicate that the medical treatment should be the same.
Boron trifluoride (BF3) seems to act similarly to hydrogen fluoride.
I'd have to research the other 3 compounds you list. Perhaps
someone else
on the listserve is more familiar with them.
Alan
Alan H. Hall, M.D.
Medical Toxicologist
ahalltoxic**At_Symbol_Here**msn.com
Date: Wed, 7 Apr 2010 12:54:51
-0400
From: karl**At_Symbol_Here**KASAI-CONSULTING.COM
Subject: Re: [DCHAS-L] HF hazards
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Does anyone know if aqueous solutions of the following fluorine containing reagents pose an HF hazard risk?
Ammonium
hexafluorophosphate – (mildly acidic solution, pH ~6)
Ammonium hexafluoroaluminate – (mildly acidic solution, pH
~6)
Ammonium tetrafluoroborate – (mildly acidic solution, pH ~6)
Ammonium fluoride
Thanks,
Karl Kasai
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