Name an aluminium compound that can be used in chromatography.

Explanation

**Step-by-Step Solution:**

1. **Understanding Chromatography**: Chromatography is a separation technique used to separate components of a mixture based on their different physical and chemical properties. It involves two phases: a mobile phase and a stationary phase.

2. **Identifying the Phases**:
- The **mobile phase** is the liquid mixture that contains the components to be separated.
- The **stationary phase** is the solid or liquid that the components of the mixture adhere to during the separation process.

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