Friday, April 25, 2014

"A Case History: The Determination of the Solid-state Structure of Triiron Dodecacarbonyl"

I tried so hard to come up with a title for this post. But, I really think there is nothing more interesting than the title above. I will write a very brief summary for the history of the compound and give some great links to read more about this fascinating story.

I built this one using Avogadro. 

image: wikipedia

Triiron Dodecacarbonyl was first synthesized by Sir James Dewar (Yes! the inventor of the Dewar flask) in 1907 and it was the third iron carbonyl complex that was discovered[1]. But, it took about 20 years for chemists to determine the molecular formula. In the next ~ 10 years, several structures were suggested by different chemists. The speculations and discussions continued and by 1963, there was enough evidence suggesting that three iron atoms were located in a triangular geometry, and two of them were equivalent (can be seen in Mossbauer spectrum below). 

In 1965,  a series of interesting events led Nils Erickson to determine the correct structure. 

He was a graduate student who was studying Mossbauer spectra of some iron complexes. But, it looks like it was not easy for him to publish his findings:

Finally in 1974, Cotton published a "further refinement" for the structure. I think this story clearly shows how important Mossbauer Spectroscopy is. I don't know when, but the first time I will look at a Mossbauer spectrum, I will definitely remember this great story.

Below you can find all the papers I have read about this complex and the events and research that led to the determination of the structure. 

3. Mossbauer Effect in Iron Pentacarbonyl and Related Carbonyls

4. Mossbauer Spectra of Iron in Na,[Fe(CO),] and Na [Fes(CO)llH1 and Comments Regarding the Structure of Fe3(CO)

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