In the structure of diborane,

Options

A. All hydrogen atoms lie in one plane and boron atoms lie in a plane perpendicular to this plane
B. 2 boron atoms and 4 terminal hydrogen atoms lie in the same plane and 2 bridging hydrogen atoms lie in the perpendicular plane.
C. 4 bridging hydrogen atoms and boron atoms lie in one plane and two terminal hydrogen atoms lie in a plane perpendicular to this plane
D. All the atoms are in the same plane

Explanation

### Step-by-Step Solution:

1. **Understanding Diborane (B2H6)**:
- Diborane is a compound formed by the dimerization of boron hydride (BH3). Since BH3 has an incomplete octet (only 6 electrons around boron), it is unstable and dimerizes to form B2H6.

2. **Counting Valence Electrons**:
- Each boron atom has 3 valence electrons. For 2 boron atoms:
\[ 2 \times 3 = 6 \text{ electrons} \]
- Each hydrogen atom has 1 valence electron. For 6 hydrogen atoms:
\[ 6 \times 1 = 6 \text{ electrons} \]
- Total valence electrons in B2H6:
\[ 6 + 6 = 12 \text{ valence electrons} \]

3. **Drawing the Structure of Diborane**:
- The structure consists of 2 boron atoms and 6 hydrogen atoms. The 4 terminal hydrogen atoms form normal covalent bonds with boron atoms, while the 2 bridging hydrogen atoms form what are known as "banana bonds".

4. **Identifying the Types of Bonds**:
- The 4 terminal B-H bonds are **two-center, two-electron bonds** (normal covalent bonds).
- The 2 bridging B-H bonds are **three-center, two-electron bonds** (also referred to as banana bonds), where each bond involves one electron from each of the two boron atoms and one from the bridging hydrogen.

5. **Analyzing the Geometry**:
- The terminal hydrogen atoms and the boron atoms lie in one plane.
- The bridging hydrogen atoms are positioned above and below this plane, making them perpendicular to the plane formed by the terminal hydrogens and borons.

6. **Conclusion**:
- The correct statement about the structure of diborane is that the two boron atoms and the four terminal hydrogen atoms lie in the same plane, while the two bridging hydrogen atoms lie in a plane perpendicular to this plane.

### Final Answer:
The correct fact about diborane (B2H6) is: **Two boron atoms and four terminal hydrogen atoms lie in the same plane, and two bridging hydrogen atoms lie in a perpendicular plane.**

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