Aluminium is extracted from bauxite by the electrolysis of aluminium oxide dissolved in cryolite. Now answer the following question:
Write the formula of cryolite.

Explanation

To answer the question regarding the formula of cryolite, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Context**:
- Aluminium is extracted from bauxite, which is the ore of aluminium. The extraction process involves electrolysis of aluminium oxide (Al2O3) dissolved in cryolite.

2. **Identifying Cryolite's Role**:
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