[Histonet] Potassium Ferrocyanide Question

[Bryan Llewellyn]

Potassium ferrocyanide is usually given the formula you first noted. 
However, my Merck Index also gives the formula C6FeK4N6 with a MW of 368.34 
(you may have a typo and left out the C6).  The differences in MW may be due 
to including or not including the 3H2O.

Just do a test Perls' stain on an iron control section.  If they are the 
same then don't worry about it.

Bryan Llewellyn



----- Original Message ----- 
From: "Greg Dobbin" <gvdobbin <@t> ihis.org>
To: <Histonet <@t> lists.utsouthwestern.edu>
Sent: Tuesday, September 25, 2007 9:32 AM
Subject: [Histonet] Potassium Ferrocyanide Question


> Hi Folks,
> Chemistry is not my forte for sure, so a little help from the chemistry
> gurus would be greatly appreciated.
>
> I purchased potassium ferrocyanide trihydrate for use in our Perl's
> stain. The bottle that is almost empty lists the contents as
> K4Fe(CN)6-3H2O with a molecular wt of 422.39.
>
> The new bottle (different supplier) uses the same name for the chemical
> ("potassium ferrocyanide trihydrate") but the formula is listed as
> FeK4N6-3H2O and the F.W. is 356.7.
>
> Can someone remind me what the "F" in F.W. stands for? And did I buy
> the right chemical? Both are ACS grade chemicals.
>
> Thank you.
> Greg
>
> Greg Dobbin, R.T.
> Chief Technologist, Histology Lab
> Dept. of Laboratory Medicine,
> Queen Elizabeth Hospital,
> P.O. Box 6600
> Charlottetown, PE    C1A 8T5
> Phone: (902) 894-2337
> Fax: (902) 894-2385
>
>
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