Date: Wed, 7 Apr 2010 11:42:03 -0700
Reply-To: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: Michael Cooper <mcooper**At_Symbol_Here**EXPONENT.COM>
Subject: Re: HF hazards
In-Reply-To: A


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,


Michael N. Cooper MS, MPH, CIH

Senior Managing Scientist

Exponent / Failure Analysis Associates

149 Commonwealth Drive

Menlo Park, California  94025


cell (408) 313-2127

office (650) 688-1760

From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**] 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

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 H. Hall, M.D.
Medical Toxicologist

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




Karl Kasai


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