When an atom has 'N' octahedral voids, the number of tetrahedral voids are:

Options

A. 8N
B. 1/2N
C. 6N
D. 2N

Explanation

To solve the question regarding the relationship between octahedral and tetrahedral voids in a crystal structure, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Relationship**:
- In a crystal lattice, for every octahedral void, there are two tetrahedral voids. This means that the number of tetrahedral voids is always twice the number of octahedral voids.

2. **Given Information**:
- We are given 'N' octahedral voids in the question.

3. **Calculating Tetrahedral Voids**:
- Since the number of tetrahedral voids is twice that of octahedral voids, we can express this mathematically:
\[ \text{Number of Tetrahedral Voids} = 2 \times \text{Number of Octahedral Voids} \]
- Therefore, substituting 'N' for the number of octahedral voids:
\[ \text{Number of Tetrahedral Voids} = 2 \times N = 2N \]

4. **Final Answer**:
- The number of tetrahedral voids when there are 'N' octahedral voids is \(2N\).