What is meant by the term "coordination number"?
b. What is the coordination number of atoms:
i. in a cubic-packed structure?
ii. In a body-centreds structure?

Explanation

### Step-by-Step Solution:

**Step 1: Define Coordination Number**
The term "coordination number" refers to the total number of nearest neighbor atoms surrounding a particular atom in a crystal structure. It quantifies how many atoms are directly adjacent to a given atom.

**Step 2: Coordination Number in a Cubic-Packed Structure**
In a cubic-packed structure, such as face-centered cubic (FCC) or simple cubic, the coordination number is determined by counting the nearest neighbor atoms around a central atom.
- In a simple cubic structure, each atom is surrounded by 6 nearest neighbors (one on each face of the cube).
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