What type of structures are exhibited by (a) `BaCl_(2) (b) Na_(2)O`

Explanation

To determine the type of structures exhibited by \( \text{BaCl}_2 \) and \( \text{Na}_2\text{O} \), we can analyze each compound step by step.

### Step 1: Analyze the structure of \( \text{BaCl}_2 \)

1. **Identify the type of compound**: \( \text{BaCl}_2 \) is an ionic compound composed of barium ions \( \text{Ba}^{2+} \) and chloride ions \( \text{Cl}^- \).
2. **Determine the coordination**: In \( \text{BaCl}_2 \), each barium ion is surrounded by two chloride ions. This gives it an AB2 type structure.
3. **Identify the structure type**: The AB2 type structure is also known as the fluoride type structure. In this case, the barium ions occupy the lattice points, while the chloride ions occupy the tetrahedral voids.
4. **Count the atoms in the unit cell**: In the structure, there are 4 barium ions and 8 chloride ions in the unit cell.
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