Among the following, metal carbonyls, the C-O bond is strongest in :

Options

A. `[Mn(CO)_(6)]^(+)`
B. `[Cr(CO)_(6)]`
C. `[V(CO)_(6)]^(-)`
D. `[Ti(CO)_(6)]^(2-)`

Explanation

To determine which metal carbonyl has the strongest C-O bond, we need to analyze the relationship between the charge on the central metal atom and the bond strength of the C-O bond in the carbonyl complexes. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Nature of Metal Carbonyls
Metal carbonyls are complexes where carbon monoxide (CO) acts as a neutral ligand. The bond between carbon and oxygen in CO is a triple bond, which contributes to its bond strength.

**Hint:** Remember that the bond order influences bond strength; higher bond order means stronger bonds.

### Step 2: Analyze the Effect of Metal Charge
The bond strength between carbon and oxygen (C-O bond) in metal carbonyls is influenced by the charge on the central metal atom. If the metal has a higher positive charge, it will have a stronger interaction with the CO ligand.

**Hint:** Consider how the oxidation state of the metal affects the electron density and back-bonding with CO.

### Step 3: Back-Bonding Concept
In metal carbonyls, back-bonding occurs when the metal donates electron density to the empty π* (anti-bonding) orbitals of CO. This back-bonding is stronger when the metal has a higher negative charge, which leads to a decrease in the C-O bond strength.

**Hint:** Recall that back-bonding stabilizes the metal-CO bond but weakens the C-O bond.

### Step 4: Determine the Oxidation States of the Metals
For the given metal carbonyls, we need to determine the oxidation states of the central metal atoms:
- Magnesium (Mg) has a charge of +1.
- Chromium (Cr) has a charge of 0.
- Vanadium (V) has a charge of -1.
- Titanium (Ti) has a charge of -2.

**Hint:** Identify the oxidation states of the metals to understand how they influence the C-O bond strength.

### Step 5: Compare the Charges
The charge on the metal atom is crucial:
- Mg (+1) has the highest positive charge.
- Cr (0) has no charge.
- V (-1) and Ti (-2) have negative charges.

Since a higher positive charge on the metal will lead to a stronger C-O bond, we conclude that the C-O bond will be strongest in the metal carbonyl with the highest positive charge.

**Hint:** Focus on the relationship between metal charge and bond strength.

### Step 6: Conclusion
Among the given metal carbonyls, magnesium carbonyl (Mg(CO)₄) has the strongest C-O bond due to the +1 charge on magnesium, which enhances the bond strength between carbon and oxygen.

**Final Answer:** The C-O bond is strongest in magnesium carbonyl (Mg(CO)₄).