[alt-photo] Making ammonium iron(III) citrate and ammonium iron(III) oxalate

[Loris Medici]

Peter, (and others)

What is the method of making ammonium iron(III) citrate? (I think this
is a little bit like cooking, since you get something depending on
method - I mean structure / composition changes with method. ???)

Also, how one can compound ammonium iron(III) oxalate?

Anyone w/ information regarding those two issues?

Thanks in advance,
Loris.

P.S. I can no longer get ammonium iron(III) citrate locally, chemical
suppliers say it is not produced anymore - by their sources. (That is
Sigma-Aldrich and/or Fluka I presume. Merck wasn't listing it
already...)


2010/5/5 Loris Medici <mail at loris.medici.name>:
> Peter, this is very interesting. Can you please elaborate? It would be
> nice to have a home recipe for making green FAC... How much of each do
> you use?
>
> TIA,
> Loris.
>
>
> 2010/5/4 Peter Friedrichsen <pfriedrichsen at sympatico.ca>:
>> Trevor,
>>
>> As far as altering it to change it to the green variety, I had no success
>> with this by adding additional ammonia and citric acid. It appears that
>> above and beyond the ratios of iron, ammonia, and citrate, the way in which
>> it is made also affects its final properties. I know this because I make my
>> own green variety from scratch.
>>
>> Essentially it is made by adding ammonia (or use ammonium bicarbonate) and
>> citric acid to iron hydroxide ( a messy red mud)  If you add the citric acid
>> first,  to make ferric citrate, then add ammonium citrate to make FAC, it
>> will make the brown variety. Now, if you add ammonium citrate + citric acid,
>> both together to this mud, then the green variety forms. So it seems that as
>> the ferric hydroxide dissolves, it must have the ammonia component
>> available, or else you will just get the brown variety, and it will stay
>> brown even if you attempt to re-balance the ratios.
>>
>> At least this is my experience.
>>
>> Peter Friedrichsen
>