How many octahedral & tetrahedral voids are per sphere in a unit cell ?

Explanation

To determine the number of octahedral and tetrahedral voids per sphere in a unit cell, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Unit Cell**:
- A unit cell is the smallest repeating unit in a crystal lattice. In this context, we consider the atoms to be represented as spheres.

2. **Defining Z**:
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