question_answer

The complex\[{{[Co{{F}_{6}}]}^{4-}}\]is

A)  outer orbital and diamagnetic

B)  inner orbital and paramagnetic

C)  inner orbital and diamagnetic

D)  outer orbital and paramagnetic

Correct Answer: D

Solution :

                In\[{{[Co{{F}_{6}}]}^{4-}},\]central metal Co is present as\[C{{o}^{2+}}\]. \[C{{o}^{2+}}=[Ar]3{{d}^{7}}4{{s}^{0}}\] Because of the presence of three unpaired electrons, the complex is paramagnetic. Moreover,\[{{F}^{-}}\]ions occupy outer d-orbitals (ie, nd-orbitals), thus it is an outer orbital complex.