[Alan]

Hi guys,

I am dealing with a kind of difficult problem....I need to synthesize iron oxalate using iron 57, due to subsequent careful mossbauer analysis I will have to perform on iron carbonate (siderite) that I will produce by mean of the former oxalate (above). So, first step is to synthesize the oxalate. However from the literature it comes out that I should always use a salt for the reaction I have to perform. Because I already posses iron 57 but in the metallic or monoxide forms (Fe metallic or FeO) I was wondering if you know a procedure to synthesize the oxalate starting from those two components. I have a well equipped chemistry lab that I can use, so I would "just" need the right receipt from somebody that already know how to do it...Without the risk to loose important and expensive starting material.

Thanks in advance!

Valerio

[Arkcon]

Since you have a protocol that uses the salt, you should start with a salt.  The oxide will probably dissolve in strong hydrochloric acid to make iron chloride.  The free metal will react slowly with hydrochloric, but will react fairly fast with nitric acid.

[Alan]

Yes you're right! I talked also with some people here in the institute and they suggest me the same.. However I found a almost straightforward way starting from the metal, so at the moment I'm trying with normal iron and if it works I'll switch to the 57Fe. Then if it could be interesting for you I ll write the procedure step by step in case somebody else could need it in the future!

thanks again

[Tittywahah]

Yes you're right! I talked also with some people here in the institute and they suggest me the same.. However I found a almost straightforward way starting from the metal, so at the moment I'm trying with normal iron and if it works I'll switch to the 57Fe. Then if it could be interesting for you I ll write the procedure step by step in case somebody else could need it in the future!

thanks again

Hi there, I have just joined today, So co-incidental to read this.  I am about (in the next couple of days) to make Ferric Oxalate.  But my method will be first by Steel wool into hydrochloric acid, then oxalic acid and ferric chloride ot get the ferric oxalate.  Fe+2HCl=FeCl2....then....FeCl2+H2C2O4=FeC2O4+2HCl

Going by the stoichemetry I will react 5.5g steel wool (will filter off carbon of course) with around 6mLs (7.2g) 36% HCl.   Then add 12.6g Oxalic dihydrate to arrive at the ferric oxalate.  (First try), I am home chemist not experienced but working on that one daily.

[Arkcon]

You might have better results using an excess of acid.  Strict stoichiometry is important for problems, and for certain chemical reactions, but as the the HCl is consumed, the last bit will find it harder and harder to find the last bit of iron.  Plus, you will lose some HCl, to room temperature fuming of HCl vapor, to evaporation, since this reaction will generate heat, and to some that just sprays out of the beaker if some hydrogen is produced -- and you will get some, even though iron should just oxidize in hardware store strength HCl.

[Tittywahah]

You might have better results using an excess of acid.  Strict stoichiometry is important for problems, and for certain chemical reactions, but as the the HCl is consumed, the last bit will find it harder and harder to find the last bit of iron.  Plus, you will lose some HCl, to room temperature fuming of HCl vapor, to evaporation, since this reaction will generate heat, and to some that just sprays out of the beaker if some hydrogen is produced -- and you will get some, even though iron should just oxidize in hardware store strength HCl.

Hallo Arkcon, thankyou for the tip.  I was afraid that since Oxalic acid is not that soluble, around 14g/100mLs water, that not all the oxalic would bind with the Iron and therefore some oxalic would remain un-precipitated being kept in solution by too much HCl (if I were to add more than necessary).  I guess this is nit-picking I suppose?  Anyway thankyou. 

[ajkoer]

Actually, vinegar and Bleach (NaOCl) forms a dilute solution of HOCl (and Sodium acetate) that will attack Iron. My speculation is that the final product is a Ferric salt (chloride or acetate).

Making Hypochlorous acid from HCl + H2O2 also works, but caution yourself for a vigorous reaction with Iron. Chlorine gas is also liberated so perform in a fume hood or outdoors.

Add the Ferric salt to your H2C2O4 to prepare the Ferric oxalate. Avoid excess Oxalic acid as the Ferric oxalate will dissolve (due to complex formation).

[Tittywahah]

Actually, vinegar and Bleach (NaOCl) forms a dilute solution of HOCl (and Sodium acetate) that will attack Iron. My speculation is that the final product is a Ferric salt (chloride or acetate).

Making Hypochlorous acid from HCl + H2O2 also works, but caution yourself for a vigorous reaction with Iron. Chlorine gas is also liberated so perform in a fume hood or outdoors.

Add the Ferric salt to your H2C2O4 to prepare the Ferric oxalate. Avoid excess Oxalic acid as the Ferric oxalate will dissolve (due to complex formation).

Hi.  Tend for the moment to avoid Hypochlorous acid, though as an experiment certainly will look into it, I have thiosulphate ions (sodium) to test for Iron 3 in solution and so happy to experiment with your suggestion, but for the moment will keep on original track - since I want to ensure a definitive outcome as this ferric oxalate will be combined to make another light sensitve solution.  Though your suggestions are noted in my to-do list when this one is done.  And appreciations for the input.

[Alan]

Hi guys, sorry for the late reply...

First thing I didn't consider at the beginning is we have to work under inert atmosphere! The way to do that are several, one can bubble nitrogen in the solution for 20 to 30 minutes or freeze the solution using liquid nitrogen ( of course separated in a different container) and remove the oxygen from the vessel containing the solution flushing argon or N2 (procedure that should be repeated at least 3 times).

When no more oxygen is present in the solution and above it, then one can start the reaction, which can be done differently, depending on the purposes... I am doing that starting from acetic acid, but also HCl is a good way, or even using other solvent for instance sulfuric acid! Even if looking in the web people say they synthesize ferric oxalate without any particular interest on the atmosphere, this is simple not possible...It will oxidize giving some Fe III compounds!

CIAO!

ps It doesn't matter if the pH of the solution is very low (like when using sulfuric acid), if there is oxygen, no way to synthesize ferric oxalate.

[Borek]

First thing I didn't consider at the beginning is we have to work under inert atmosphere!

I suppose it depends on how pure product you need and what is the sample size. If you have plenty of iron and you don't care about some small amount of impurities, using freshly boiled water and keeping the solution covered can be enough. OTOH if the sample is small and you have to avoid even traces of Fe(III) then yes, inert atmosphere is a must.