question_answer

In \[Fe{{(CO)}_{5}}\], the \[Fe\leftarrow CO\,\sigma \] bond results by the overlap between filled sp hybrid orbital of C-atom of CO molecule and vacant hybrid orbital of Fe atom.

A)  \[{{d}^{2}}s{{p}^{3}}\]  

B)  \[s{{p}^{3}}\]   

C)  \[ds{{p}^{3}}\]   

D)  \[ds{{p}^{2}}\]  

Correct Answer: C

Solution :

\[_{26}Fe=[Ar]\,3{{d}^{6}}4{{s}^{2}}\] In \[Fe{{(CO)}_{5}}\], CO being strong field ligand, causes pairing. Thus, Fe in Fe \[{{(CO)}_{5}}=[Ar]\] Thus, CO overlaps with the \[ds{{p}^{3}}\]hybrid orbitals of Fe atom.