March 28, 2024, 05:04:38 PM
Forum Rules: Read This Before Posting


Topic: Reaction for light-sensitive potassiumtris(oxalato)ferrate(III)  (Read 8436 times)

0 Members and 1 Guest are viewing this topic.

Offline Fmeub

  • Regular Member
  • ***
  • Posts: 35
  • Mole Snacks: +0/-0
Hi!

I know that the crystal surfaces of potassiumtris(oxalato)ferrate(III) will turn yellow if they are not stored in the dark, but how do I explain it by using reaction equations?

I suppose the light gives energy in the form hv, but I'm not sure whether any bonds break.


Offline resc

  • New Member
  • **
  • Posts: 7
  • Mole Snacks: +2/-1
Re: Reaction for light-sensitive potassiumtris(oxalato)ferrate(III)
« Reply #1 on: May 27, 2008, 02:24:21 PM »
Hi

The photosensitive nature of this compound is used in actinometry (look up ferrioxalate actinometry). Light reduces the Fe3+ to Fe2+ and the oxalate form CO2:

2Fe3+ + C2O42- (hv) --> 2Fe2+ + 2CO2

You can then add something like 1,10-phenanthroline if you want to quantify the Fe2+ and hence the amount of photons, by measuring the absorption of the iron-phenanthroline complex.

So in answer to your question, bonds do break as the complex goes via an excited state, and one of the pathways deactivating this excited state is decomposition.

Sponsored Links