[Alt-photo] ferrous vs. ferric

Christina Z. Anderson christinazanderson at gmail.com
Tue Mar 22 13:55:53 UTC 2016

Chemistry question here:

I apologize that I did not follow the discussion of the last several months about hard-to-dissolve ferric oxalate because I always buy mine ready-mixed from Bostick following a discussion years ago about this very issue. I’ve never used it dry. Their solution lasts a couple years and if I buy a large quantity I store it in the fridge and it has never gone bad on me.

I am wondering though whether buying it in the powder form is a) a good idea and b) has a longer shelf life?

Am I correct in assuming ferric can change to ferrous with age?

And that ferrous is harder to dissolve than ferric?

And that if your “ferric oxalate” powder is hard to dissolve/never dissolves that means it  has changed to the ferrous form?

I guess I am just trying to ascertain whether there is any benefit to buying and storing the powder and how long the shelf life is. I assume people mostly do this for the cost savings if they are uber-platinum printers doing it on a daily basis (like I buy gum by the gallon).


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