Ferric oxilate

[adam lubroth]

• • I recently bought Ferrous ( Fe II) Oxalate instead of Ferric ( Fe III ) Oxalte because of an incorrect translation from German.
  So.... does anyone know of a way to go from Ferrous to Ferric ? All suggestions most appreciated.
  thanks
  Adam
  

 

[Herzeleid]

Reaction is simple
2 FeC2O4 + C2H2O4 = Fe2(C2O4)3 + 2 H
https://www.webqc.org/balance.php?reaction=FeC2O4+C2H2O4=Fe2(C2O4)3+H
15.31 gr Ferrous Oxalate
4.79 gr Oxalic acid
will give you 20 gr of Ferric oxalate.
Prepare in less than 100ml, final step you can adjust it to 100ml.

But things don't go as smooth as you might expect. You will need a concentrated solution of hydrogen peroxide (%30 - 50 preferably) to oxidize ferrous to ferric and it is an exothermic reaction.
It might decompose some oxalic acid so you might need to add some oxalic acid later drop by drop.

Follow the steps after 4, you will need to adjust it to your working batch.
http://www.ericneilsenphotography.com/free_papers/Ferric Oxalate Making Liquid.pdf

If you are going to make kallitypes excess oxalic acid or residual ferrous will ruin your prints quality and longevity. For Pt/pd excess oxalic wont hurt and iron residue can be cleared easily with chemical treatment.

Regards

 

[adam lubroth]

Thanks !
this is perfect.
Is it important to have exact weight? my balance is rather limited

 

[Herzeleid]

It is important if you are to have a total conversion of ferrous oxalate.
Check this link, enter the grams you can measure and try to adjust accordingly.
https://www.webqc.org/balance.php?reaction=FeC2O4+C2H2O4=Fe2(C2O4)3+H

 

[adam lubroth]

This link is amazing.
thanks again