What is the distance between two `TVs`?

Explanation

To find the distance between two tetrahedral voids in a crystal structure, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure**:
Tetrahedral voids are formed in a crystal lattice where spheres (atoms) are arranged in a specific pattern. In a face-centered cubic (FCC) structure, tetrahedral voids are located at certain positions relative to the atoms.

2. **Identify the Body Diagonal**:
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