How many `pi`-bonds are presennt in ferrocene?

Explanation

To determine the number of π-bonds present in ferrocene, we can follow these steps:

### Step 1: Understand the Structure of Ferrocene
Ferrocene consists of an iron (Fe) atom sandwiched between two cyclopentadienyl (Cp) rings. Each Cp ring is a five-membered carbon ring with alternating double bonds.

### Step 2: Analyze the Cyclopentadienyl Ring
Each cyclopentadienyl ring has:
- 5 carbon atoms.
- 2 double bonds (which contribute to π-bonds).
- The π-electrons are delocalized across the ring.

### Step 3: Count the π-Bonds in One Cyclopentadienyl Ring
In one cyclopentadienyl ring:
- There are 2 double bonds, which means there are 2 π-bonds.

### Step 4: Consider Both Cyclopentadienyl Rings
Since ferrocene has two cyclopentadienyl rings:
- Each ring contributes 2 π-bonds.
- Therefore, for two rings: 2 π-bonds/ring × 2 rings = 4 π-bonds.

### Step 5: Consider the Delocalization of Electrons
In addition to the double bonds, the cyclopentadienyl rings have delocalized π-electrons:
- Each ring has 6 π-electrons (due to resonance).
- Thus, the total number of π-electrons in both rings is 6 π-electrons/ring × 2 rings = 12 π-electrons.

### Step 6: Determine the Number of π-Bonds
Since each π-bond consists of a pair of π-electrons:
- Total number of π-bonds = Total number of π-electrons / 2.
- Therefore, 12 π-electrons / 2 = 6 π-bonds.

### Conclusion
Thus, the total number of π-bonds present in ferrocene is **6**.

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