Does cyclopentadienyl iron dicarbonyl dimer have a metal–metal bond? Who's asking?
In a 2012 essay, Green, Green and Parkin noted that certain bridged carbonyl complexes, including [CpFe(CO)_2]_2 (Cp = η^5-cyclopentadienyl), are commonly depicted with an explicitly-drawn metal–metal bond in textbooks, and presented a rationale for why that constitutes a misrepresentation. Here I briefly summarize the history of that compound, in which Cotton played a major part, and try to show that there are at least equally valid justifications for keeping the M–M bond in the picture. More generally, I will argue against the idea of a single "best" representation of a complex molecule, by drawing upon analogies to literary translation.
© 2014 Elsevier B.V. Received 14 March 2014; Received in revised form 17 April 2014; Accepted 19 April 2014; Available online 10 May 2014. I thank Harry Gray, Steve Weininger, and John Bercaw for helpful comments.