Which of the following has the longest C-O bond length? (Free C-O bond length in CO is 1.128 oversetoA ).

Question

Which of the following has the longest C-O bond length? (Free C-O bond length in CO is 1.128 oversetoA ). (A) Ni(C O)4 (B) [ Co ( CO )4]- (C) [ Fe ( CO )4]2- (D) [ Mn ( CO )6]+

Tardigrade Admin · Accepted Answer

Metal carbon bond in metal carbonyls possess both

σ

and

π

character.

M - C

π

bond is formed by donation of a pair of electrons from filled orbital of metal into vacant antibonding

π

orbital of

CO

.

CO

bond length increases if M has more tendency to donate lone pair.
Tendency to donate lone pair is

F e^{2 -} > C o^{-} > N i > M n^{+}

Q. Which of the following has the longest $C - O$ bond length? (Free $C - O$ bond length in $CO$ is $1.128 A o$ ).

$N i (CO)_{4}$

$[C o (CO)_{4}]^{-}$

$[F e (CO)_{4}]^{2 -}$

$[M n (CO)_{6}]^{+}$

Q. Which of the following has the longest C−O bond length? (Free C−O bond length in CO is 1.128Ao ).

Ni(CO)4​

[Co(CO)4​]−

[Fe(CO)4​]2−

[Mn(CO)6​]+

Q. Which of the following has the longest $C - O$ bond length? (Free $C - O$ bond length in $CO$ is $1.128 A o$ ).

$N i (CO)_{4}$

$[C o (CO)_{4}]^{-}$

$[F e (CO)_{4}]^{2 -}$

$[M n (CO)_{6}]^{+}$