Lanthanide compounds are less basic than actinide compounds.

Explanation

To determine whether lanthanide compounds are less basic than actinide compounds, we can analyze the electronic configurations and the resulting chemical properties of these two series of elements.

### Step-by-Step Solution:

1. **Identify the Electron Configurations:**
- Lanthanides have their outermost electrons filling the 4f subshell. The general electron configuration for lanthanides is [Xe] 6s² 4f¹⁻¹⁴.
- Actinides have their outermost electrons filling the 5f subshell. The general electron configuration for actinides is [Rn] 7s² 5f¹⁻¹⁴.

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