Which of the following bond order is indication of existence of a molecule ?

Options

A. Zero bond order
B. Negative bond order
C. Positive bond order
D. All of these.

Explanation

To determine which bond order indicates the existence of a molecule, we can analyze the bond orders and their implications:

### Step-by-Step Solution:

1. **Understanding Bond Order**:
- Bond order is defined as the difference between the number of bonding electrons and the number of anti-bonding electrons, divided by two. The formula is:
\[ \text{Bond Order} = \frac{\text{Number of Bonding Electrons} - \text{Number of Anti-bonding Electrons}}{2} \]

2. **Analyzing Zero Bond Order**:
- A bond order of zero indicates that there are equal numbers of bonding and anti-bonding electrons. This means that there is no net bond between the atoms, and therefore, the molecule does not exist.

3. **Analyzing Negative Bond Order**:
- A negative bond order also indicates that there are more anti-bonding electrons than bonding electrons. This further confirms that the molecule cannot exist.

4. **Analyzing Positive Bond Order**:
- A positive bond order indicates that there are more bonding electrons than anti-bonding electrons. This suggests that there is a net attractive force between the atoms, and thus, the molecule exists.

5. **Conclusion**:
- Based on the analysis, a positive bond order is the only indication of the existence of a molecule. Therefore, the correct answer to the question is "positive bond order".