Which statement is true for ferrocene ?

Options

A. All Fe-C are of equal length
B. C are `sp^(2)` hybridized
C. It was the first discovered organometallic compound
D. All of these

Explanation

To determine which statement is true for ferrocene, we can analyze the properties and structure of the compound step by step.

### Step 1: Understand the Structure of Ferrocene
Ferrocene is an organometallic compound with the formula Fe(C5H5)2. It consists of an iron (Fe) atom sandwiched between two cyclopentadienyl (C5H5) anions. The structure can be visualized as two cyclopentadienyl rings (which are planar) that are parallel to each other with the iron atom in between.

**Hint:** Remember that the structure of ferrocene is often referred to as a "sandwich" structure due to the arrangement of the cyclopentadienyl rings around the iron atom.

### Step 2: Analyze the Bonding
In ferrocene, the iron atom forms bonds with the carbon atoms of the cyclopentadienyl rings. The Fe-C bond lengths are equal, indicating that the bonding is symmetrical. This symmetry is a characteristic feature of the compound.

**Hint:** Look for symmetry in the structure when analyzing organometallic compounds, as it often indicates equal bond lengths and similar bonding characteristics.

### Step 3: Determine Hybridization
The carbon atoms in the cyclopentadienyl rings are sp² hybridized. This is because each carbon atom in the ring is bonded to two other carbon atoms and has one p orbital that contributes to the delocalized π system of the ring.

**Hint:** Recall that sp² hybridization involves one s orbital and two p orbitals, leading to a trigonal planar arrangement around each carbon atom.

### Step 4: Historical Context
Ferrocene was the first organometallic compound to be synthesized, which occurred in the 1950s. Its discovery marked a significant advancement in the field of organometallic chemistry.

**Hint:** Consider the historical significance of compounds when discussing their properties; knowing when a compound was discovered can provide context for its importance.

### Conclusion
Based on the analysis:
1. All Fe-C bonds in ferrocene are equal.
2. The carbon atoms in the cyclopentadienyl rings are sp² hybridized.
3. Ferrocene is indeed the first discovered organometallic compound.

Thus, the correct answer to the question is that all of the statements regarding ferrocene are true.

**Final Answer:** All of the above statements are true for ferrocene.