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

Explanation

To determine the number of tetrahedral and octahedral sites in a close packing of \( N \) spheres, we can follow these steps:

### Step 1: Understanding Close Packing
In close packing arrangements such as face-centered cubic (FCC) or hexagonal close-packed (HCP), spheres are arranged in a way that maximizes space efficiency. In these arrangements, we can identify the types of voids (spaces not occupied by spheres) that can be formed.

### Step 2: Identifying Octahedral Sites
In a close-packed structure:
- Each sphere contributes to the formation of octahedral voids.
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