The correct statements about metal carbonyls are A. The metal-carbon bonds in metals carbonyls possess both \(\sigma\) and \(\pi\)-character. B. Due to synergic bonding interactions between metals and CO ligand the metal-carbon bond becomes weak. C. The metal-carbon \(\sigma\) bond is formed by the donation of lone pair of electrons on the carbonyl carbon into a vacant orbital of metal. D. The metal-carbon \(\pi\) bond is formed by the donation of electrons from filled d-orbital of metal into vacant \(\pi^{*}\) orbital of CO. Choose the correct answer from the options given below:

JEE Main · 2026 · 05 Apr 2026 · Shift 1 · Coordination Compounds

The correct statements about metal carbonyls are
A. The metal-carbon bonds in metals carbonyls possess both

σ

and

π

-character.
B. Due to synergic bonding interactions between metals and CO ligand the metal-carbon bond becomes weak.
C. The metal-carbon

σ

bond is formed by the donation of lone pair of electrons on the carbonyl carbon into a vacant orbital of metal.
D. The metal-carbon

π

bond is formed by the donation of electrons from filled d-orbital of metal into vacant

π^{*}

orbital of CO.
Choose the correct answer from the options given below:

(A)A and B only
(B)A, C and D only✓ Correct
(C)B and C only
(D)A and D only

Answer: (B)

Solution

The metal–carbon linkage in a carbonyl has two components, a

σ

bond and a

π

bond, so statement A is correct. The

σ

bond forms when the lone pair on the carbonyl carbon is donated into a vacant metal orbital, as in statement C, and the

π

bond forms when a filled metal

d

orbital back-donates into the empty

π^{*}

orbital of CO, as in statement D; both are correct. This donation and back-donation act synergically and strengthen, rather than weaken, the metal–carbon bond, so statement B is wrong. The correct statements are A, C and D.

JEE Main · 2026 · 05 Apr 2026 · Shift 1 · Single correct option

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JEE Main · 2026 · 05 Apr 2026 · Shift 1 · Coordination Compounds

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