Question

Which of the following statement is correct regarding metal carbonyl ?

• A. In Mn${}_2$(CO)${}_{10}$, bond order of Mn-Mn is 0
• B. In Fe${}_2$(CO)${}_9$, number of Fe-Fe bonds is 1
• C. In Ni(CO)${}_4$, all bond length are same
• D. Fe(CO)${}_5$ is diamagnetic

Answer 1

Answer: (B), (C), (D)

The correct options are
B In Fe${}_2$(CO)${}_9$, number of Fe-Fe bonds is 1
C In Ni(CO)${}_4$, all bond length are same
D Fe(CO)${}_5$ is diamagnetic

$Fe(CO{)}_5$: Due to strong ligand pairing molecule is diamagnetic.
Ni(CO)${}_4$: $d^{10};s{p}^3$ hybridization so does not contain any unpaired electron and posses tetrahedral structure, hence, all bond lengths are same.
Bond order of $Mn-Mn$ in $M{n}_2(CO{)}_{10}$ is 1.