Aluminium fluorirde is ionic but aluminium chloride is covalent. Explain

Explanation

### Step-by-Step Solution:

1. **Understanding Ionic and Covalent Bonds**:
- Ionic bonds typically form between elements with a large difference in electronegativity (greater than 1.9). In contrast, covalent bonds form when the electronegativity difference is smaller (less than 1.9).

2. **Electronegativity Values**:
- The electronegativity of Aluminium (Al) is approximately 1.5.
- The electronegativity of Fluorine (F) is about 4.0.
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