Which one is not a borane ?

Options

A. `B_5 H_9`
B. `B_5 H_(10)`
C. `B_5 H_(11)`
D. `B_6 H_(10)`

Explanation

To determine which compound is not a borane, we can follow these steps:

### Step 1: Understand the Classification of Boranes
Boranes can be classified into two main categories:
1. **Nidoboranes** - These have the general formula \( B_nH_{n+4} \).
2. **Arachnoboranes** - These have the general formula \( B_nH_{n+6} \).

### Step 2: Analyze the Given Options
We need to evaluate the options based on the formulas provided. Let's denote the options as follows:
1. \( B_5H_9 \)
2. \( B_5H_{10} \)
3. \( B_5H_{11} \)
4. \( B_6H_{10} \)

### Step 3: Determine Which Options Fit the Borane Classification
- For **Nidoboranes**:
- If \( n = 5 \), then \( B_5H_{n+4} = B_5H_9 \) (This is a Nidoborane).
- If \( n = 6 \), then \( B_6H_{n+4} = B_6H_{10} \) (This is also a Nidoborane).

- For **Arachnoboranes**:
- If \( n = 5 \), then \( B_5H_{n+6} = B_5H_{11} \) (This is an Arachnoborane).

### Step 4: Identify the Non-Borane
Now, we can see that:
- \( B_5H_9 \) is a Nidoborane.
- \( B_5H_{10} \) does not fit either formula (neither Nidoborane nor Arachnoborane).
- \( B_5H_{11} \) is an Arachnoborane.
- \( B_6H_{10} \) is a Nidoborane.

### Conclusion
The compound that is not a borane is **\( B_5H_{10} \)**.

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