Chemistry Forum

I have an assignment and i am stuck on all parts of this question! If someone could answer it, it would be amazing! I have to submit my paper in 8 hours and was going to skip this question!

1. (i) Use group theory to predict the number of (CO) stretching
vibrations you would expect to observe in the IR and Raman
spectra of all sensible isomers of Fe(CO)₄(PPh₃).
(10 marks)


(ii) Can these isomers be differentiated by IR and/or 13C {
1H}
spectroscopy at room temperature? Fully explain your answer in
both cases.
(10 marks)


(iii) Fe(CO)₅ is relatively unstable and upon standing converts into
a green solid. What is the latter? Give a balanced equation.
Would you expect to be able to differentiate between these two
iron carbonyls on the basis of IR spectroscopy? (you do not need
to give a full group theory analysis)
(5 marks)


(iv) Explain why Fe(CO)₄(PPh₃) does not decompose in a similar
manner but is sensitive to oxidative decay.
(5 marks)

I dont have knowledge in Raman Spectroskopy.
But iii I think I can answer.
3 Fe(CO)₅ => Fe₃(CO)₁₂ + 3 CO green
Also 2 Fe(CO)₅ => Fe₂(CO)₉ + CO yellow
iv I think its because of the Triphenylphosphan, what is sensitive to oxygen.