Number of complexes which will exhibit synergic bonding amongst, \([Cr(CO)_6]\), \([Mn(CO)_5]\) and \([Mn_2(CO)_{10}]\) is ________.

Question

In the following species, how many species have the same magnetic moment?
(i) Cr\(^{2+}\)
(ii) Mn\(^{3+}\)
(iii) Ni\(^{2+}\)
(iv) Sc\(^{2+}\)
(v) Zn\(^{2+}\)
(vi) V\(^{3+}\)
(vii) Ti\(^{4+}\)

Answer 1

The problem asks which of the given metal carbonyl complexes exhibit synergic bonding. Synergic bonding, in the context of metal carbonyls, involves a back-donation process where electrons move from the filled metal d-orbitals to the empty π* orbitals of CO ligands. This dual interaction of σ-donation and π-back donation leads to stabilization of the complex.

Let's analyze the complexes:

[Cr(CO)₆]: Chromium has a d⁶ configuration. In [Cr(CO)₆], each CO ligand donates electrons to chromium through σ-bonding, while simultaneous back-donation occurs from chromium’s filled d-orbitals to the π* antibonding orbitals of CO. Therefore, [Cr(CO)₆] exhibits synergic bonding.
[Mn(CO)₅]: This is an important point of analysis. However, [Mn(CO)₅] is typically unlikely due to the common oxidation states and bonding preferences of manganese. [Mn₂(CO)₁₀] is the common stable form.
[Mn₂(CO)₁₀]: Each Mn centers have electrons in their d-orbitals to donate back to CO’s π* orbitals. Thus, synergic bonding exists here too.

Given this analysis:

[Cr(CO)₆] and [Mn₂(CO)₁₀] exhibit synergic bonding.

Based on the analysis, the number of complexes exhibiting synergic bonding is 2, falling within the provided range of 3.

Number of complexes which will exhibit synergic bonding amongst, \([Cr(CO)_6]\), \([Mn(CO)_5]\) and \([Mn_2(CO)_{10}]\) is ________.

Correct Answer: 3

Solution and Explanation

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