Sciencemadness Discussion Board

Fe oxalate complexes

The Austrian Scientist - 2-1-2018 at 04:59

Hi,

does anyone have experience with iron oxalate complexes like

[Fe(C2O4)3]2- or [Fe(C2O4)2]2-?

[Edited on 2-1-2018 by The Austrian Scientist]

j_sum1 - 2-1-2018 at 05:34

Well, FeC2O4 is highly insoluble and getting it to do anything except precipitate might be difficult. I doubt you coUKld form a complex with excess oxalate.

And the first compound you suggested, [Fe(C2O4)3]2- has iron in a +4 oxidation state. I don't think you will find that stable.

Care to give some context as to why you are asking the question?

The Austrian Scientist - 2-1-2018 at 05:40

Sorry, I meant [Fe(C2O4)3]3-

I want to explore the chemistry of these complexes and prepare salts with different metals.


mayko - 2-1-2018 at 08:12

I've made some ammonia complexes of misc. transition metal oxalates. Iron oxalate seems to be very prone to oxidation under basic conditions though, and I've never been able to isolate this complex.



The Austrian Scientist - 2-1-2018 at 08:17

I hope this doen´t bother me, since i am not working in an basic environment.

happyfooddance - 2-1-2018 at 08:21

If you have soluble ferrous salts, it's as easy as adding oxalic acid, and heating/stirring, and filtering the precipitate.

Edit: Polverone's suggestion on this page http://www.sciencemadness.org/talk/viewthread.php?tid=18418 works well, I made a bunch of iron (II) oxalate recently using this method.

1514910383421641969355.jpg - 2.1MB

[Edited on 1-2-2018 by happyfooddance]

The Austrian Scientist - 2-1-2018 at 08:30

But this precipitats FeC2O4 * 2 H2O(wich i have already made), but i want to complex it wit a nother oxalate ion to optain the [Fe(C2O4)2]2- complex.

Thanks thoug.



[Edited on 2-1-2018 by The Austrian Scientist]

happyfooddance - 2-1-2018 at 08:39

Oh, my bad

elementcollector1 - 2-1-2018 at 21:36

Complexing it to the trioxalatoferro ion is as simple as adding hydrogen peroxide and an excess of oxalic acid. You should see the liquid above the solution turn a vivid, radioactive yellow-green.

happyfooddance - 2-1-2018 at 21:49

Quote: Originally posted by elementcollector1  
Complexing it to the trioxalatoferro ion is as simple as adding hydrogen peroxide and an excess of oxalic acid. You should see the liquid above the solution turn a vivid, radioactive yellow-green.


I have done this, but how do you isolate the solid? Just boil off the liquid? I tried evaporating this solution, I was getting black junk.

DraconicAcid - 2-1-2018 at 22:02

The complex is photosensitive. If you make it in concentrated enough solution, it should crystallize nicely upon cooling.

The Austrian Scientist - 2-1-2018 at 23:46

Thanks for the support.

The Trioxalatoferrate thoug i plan to prepare by adding
(NH4)2C2O4 to a FeCl3 solution.

FeCl3 + 3 (NH4)2C2O4 -> (NH4)3[Fe(C2O4)3] + 3 NH4Cl

The FeC2O4 * 2 H2O is for the dioxalatoferrate(II)