[cyrosceals]

Hi everyone. Which of the transition metal in the following species has an unpaired electron in a d orbital?

A. TiCl4
B. MnO₄^2-
C. [FeCl₄]^-
D. [Co(NH₃)₆]³⁺

The answer is MnO₄^2- but I dont really understand why. I guess that the ligands in the rest of the complex ions also donate electrons to the charged transition ions?

Anyone please help. Its my exam period and Im looking through past papers to see any things I dont know.

Thanks.

[cliverlong]

Does the following help at all?

http://www.chemguide.co.uk/inorganic/complexions/whatis.html

It contains some examples of how the d-orbitals of transition metals ar einvovled in bonding - but from my quick scan ocuses on the bonding of ligands to transition metal ions - so may not be fully helpful.


Clive

[Rudi]

The answer is MnO₄^2- but I dont really understand why.

You just have to count the d-Electrons. Mn(VI) in MnO₄^2- owns only one of them.

I guess that the ligands in the rest of the complex ions also donate electrons to the charged transition ions?

No that is not the case. Ti(IV) in TiCl4 has d0 configuration and for the Co(III) complex the six d-electrons are paired due to the low-spin configuration.

It might be worth noting that Fe(III) in complex C has d5 high-spin configuration and, thus, five unpaired electrons.