I was given a question to draw the structure of $\ce{Fe(CO)6}$ and tell the hybridization. Hybridization came out to be $\ce{sp^3d^2}$ and structure as Octahedral. But does $\ce{Fe(CO)6}$ really exist? I could not find anything about it on the internet.

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  • $\begingroup$ @Martin-マーチン1. Its a textbook question, although in the textbook it is written that using hybridisation is not always correct, but still questions are given. $\endgroup$ Commented May 2, 2020 at 13:39
  • $\begingroup$ @Martin-マーチン2.My question is completely different. The compound does not follow EAN rule or 18VE rule and there is no mention of it on the internet. I am just curious. $\endgroup$ Commented May 2, 2020 at 13:45
  • $\begingroup$ See this meta post for context. Our mod @Martin-マーチン, clearly explains why questions regarding 'hybridization' aren't accepted on this site. $\endgroup$ Commented May 2, 2020 at 13:56
  • $\begingroup$ @DanishJuneja First: Your textbook is wrong. This may make you sad, but that is the truth. You probably still have to use it, but if you are really curious, you keep in min, that it is wrong. Second: I know that your question is different; that doesn't make it unrelated. There was nothing more I pointed out about that. Lastly: I only provided context with the hope that it is helpful. I am sorry if that has offended you in some way. $\endgroup$ Commented May 2, 2020 at 16:03

1 Answer 1


There is an iron hexacarbonyl, not as a neutral compound but as a dication which satisfies the 18-electron rule. This along with its heavier Group 8 congeners is reported by Finze et al. [1]. The authors who report the tetrafluoroborate salts, also reference earlier work with the corresponding fluoroantimonates. The reference was found in Wikipedia.


  1. Finze, M.; Bernhardt, E.; Willner, H.; Lehmann, C. W.; Aubke, F. (2005). "Homoleptic, σ-Bonded Octahedral Superelectrophilic Metal Carbonyl Cations of Iron(II), Ruthenium(II), and Osmium(II). Part 2: Syntheses and Characterizations of [M(CO)6][BF4]2 (M = Fe, Ru, Os)". Inorganic Chemistry. 44 (12): 4206–4214. https://pubs.acs.org/doi/10.1021/ic0482483
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    $\begingroup$ So the question was given just for practice, I suppose. $\endgroup$ Commented May 2, 2020 at 14:00
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    $\begingroup$ @DanishJuneja Apparently school textbooks still teaches outdated concepts. Anyway, an organoiron complex of formula $\ce{[Fe2(µ-bdt)(CO)6]}$ has been known where bdt = benzene-1,2-dithiolate. See: unioviedo.es/jaclab/pub/p86.pdf $\endgroup$ Commented May 2, 2020 at 14:03
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    $\begingroup$ Thanks @NilayGhosh. Just to be clear: The compound cited in the comment, with two metal centers, resumably would not have the octahedral coordination of a mono-nuclear hexacarbonyl. $\endgroup$ Commented May 2, 2020 at 14:09
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    $\begingroup$ Yes, I know that. I just wanted to show OP that homoleptic, charge-neutral, binary hexacarbonyl of iron does not exist. $\endgroup$ Commented May 2, 2020 at 14:14

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