In a close placed arrangement of N spheres, how many (i) tetrahedral and (ii) octahedral sites are present ?

Explanation

To solve the question regarding the number of tetrahedral and octahedral sites present in a close-packed arrangement of N spheres, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Close Packing**:
- In a close-packed arrangement, spheres are arranged in a way that maximizes the packing efficiency. The two common types of close packing are Face-Centered Cubic (FCC) and Hexagonal Close Packing (HCP).

2. **Identifying the Number of Atoms**:
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