Bonding in Metal Carbonyls

Given below are two statements: one is labelled as “Assertion A” and the other is labelled as “Reason R”

Assertion A : In the complex $\mathrm{Ni}(\mathrm{CO}{)}_4$ and $\mathrm{Fe}(\mathrm{CO}{)}_5$, the metals have zero oxidation state.

Reason R : Low oxidation states are found when a complex has ligands capable of $\pi$-donor character in addition to the $\sigma$-bonding.

In the light of the above statements, choose the most appropriate answer from the options given below

The number of sigma and pi bonds present in ${\mathrm{Fe}}_2{\left(\mathrm{CO}\right)}_9$ respectively are

Among the given complexes that possess "$\mathrm{CO}$" ligand bridges are

$\underset{\mathrm{I}}{\left[{\mathrm{Co}}_2{\left(\mathrm{CO}\right)}_8\right]} \underset{\mathrm{II}}{ \left[{\mathrm{Fe}}_3{\left(\mathrm{CO}\right)}_{12}\right]} \underset{\mathrm{III}}{\left[{\mathrm{Mn}}_2{\left(\mathrm{CO}\right)}_{10}\right]} \underset{\mathrm{IV}}{\left[{\mathrm{Fe}}_2{\left(\mathrm{CO}\right)}_9\right]}$

In $\mathrm{Fe}{\left(\mathrm{CO}\right)}_5$

$\underset{\mathrm{I}}{{\left[\mathrm{Fe}(\mathrm{CO}{)}_4{\left({\mathrm{PPh}}_3\right)}_2\right]}^{2+}}$ $\underset{\mathrm{II}}{{\left[\mathrm{Co}\left(\mathrm{CO}{)}_4\right(\mathrm{PhO}{)}_2\right]}^{2+}}$ $\underset{\mathrm{III}}{{\left[\mathrm{V}(\mathrm{CO}{)}_4{\left({\mathrm{PF}}_3\right)}_2\right]}^{2+}}$ $\underset{\mathrm{IV}}{{\left[\mathrm{Mn}{\left(\mathrm{CO}\right)}_4{\left({\mathrm{PCl}}_3\right)}_2\right]}^{2+}}$

Arrange the following in the decreasing order of $\mathrm{C}-\mathrm{O}$ bond length.

Which of the following complexes has the strongest metal-carbon bond?

The number of bridging carbonyls in ${\mathrm{Co}}_2{\left(\mathrm{CO}\right)}_8$ is

 Homonuclear metal carbonyls are those that have two or more than two metal centres but are of the same type.

An example of homonuclear metal carbonyl is

How the polynuclear metal carbonyls are classified on the basis of type of metals?

Write a note on the classification of metal carbonyls.

The transition metal in which of the following compound has zero oxidation state?

The correct pair of orbitals involved in $\pi$ -bonding between metal and $\mathrm{CO}$ in metal carbonyl complexes is:

Which of following involves maximum $\mathrm{C}-\mathrm{O}$  bond length :-

Carbon monoxide is a very common ligand in organometallic chemistry. It is particularly good at stabilising low oxidation states of central metal such as Fe(CO)₅.

When $\mathrm{CO}$ approaches metal as ligand, a sigma bond is formed as a result of overlap of lone pair of carbon atom and empty hybridised orbital of metal. Apart from it, empty $\mathrm{CO}$ antibonding orbital accepts $\text{π}$-electron density from the filled $\mathrm{d}$-orbitals on the metal atom side by side, which is sometimes also referred as $\text{π}$-back bonding.

Carbon monoxide is not appreciably nucleophilic, i.e., $\text{σ}$-bond formed with metal is weak. But many $\mathrm{d}$-metal carbonyl compounds are very stable. Thus, we can infer that the strength of $\text{π}$-back bonding enhances the stability of carbonyl complexes by increasing the strength of $\text{σ}$-bond between metal and carbonyl.

Which of the following has shortest metal carbon bond ?

Carbon monoxide is a very common ligand in organometallic chemistry. It is particularly good at stabilising low oxidation states of central metal such as Fe(CO)₅.

When CO approaches metal as ligand, a sigma bond is formed as a result of overlap of lone pair of carbon atom and empty hybridised orbital of metal. Apart from it, empty CO antibonding orbital accepts $\text{π}$-electron density from the filled d-orbitals on the metal atom side by side, which is sometimes also referred as $\text{π}$-back bonding.

Carbon monoxide is not appreciably nucleophilic, i.e., $\text{σ}$-bond formed with metal is weak. But many d-metal carbonyl compounds are very stable. Thus, we can infer that the strength of $\text{π}$-back bonding enhances the stability of carbonyl complexes by increasing the strength of $\text{σ}$-bond between metal and carbonyl.

The longest $\mathrm{CO}$ bond length will be with

Correct statement for these compounds is :

(i) $\mathrm{Co}{\left(\mathrm{CO}\right)}_6$

(ii) $\mathrm{Co}{\left(\mathrm{CO}\right)}_5{\mathrm{NH}}_3$

(iii) $\mathrm{Co}{\left(\mathrm{CO}\right)}_4{\left({\mathrm{NH}}_3\right)}_2$

(iv) $\mathrm{Co}{\left(\mathrm{CO}\right)}_3{\left({\mathrm{NH}}_3\right)}_3$

(v) $\mathrm{Co}{\left(\mathrm{CO}\right)}_2{\left({\mathrm{NH}}_3\right)}_4$

(vi) $\mathrm{Co}\left(\mathrm{CO}\right){\left({\mathrm{NH}}_3\right)}_5$

The coordination geometry around the manganese in decacarbonyldimanganese$\left(0\right)$

In which one of the following metal carbonyls, $\mathrm{CO}$ forms a bridge between metal atoms?

Shape of ${\mathrm{Mn}}_2{\left(\mathrm{CO}\right)}_{10}$