What ist the coordination number of each ion present in the closed packed sturctures of (a) `Na_(2) O` (b) `CaF_(2)` at ordinary temperature and pressure?

Explanation

To determine the coordination number of each ion present in the closed-packed structures of sodium oxide (Na₂O) and calcium fluoride (CaF₂) at ordinary temperature and pressure, we can analyze their crystal structures step by step.

### Step-by-Step Solution:

**(a) Sodium Oxide (Na₂O)**

1. **Identify the Structure**: Sodium oxide crystallizes in a face-centered cubic (FCC) structure. In this structure, oxygen atoms are located at the corners and face centers of the cube.

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