For which lanthanide are +2 and +3 oxidation states are common?

Eu

Among the lanthanides, europium (Eu) is the primary element that commonly exhibits both the +2 and +3 oxidation states. The +2 oxidation state is more stable for europium compared to the +3 oxidation state. In many europium compounds, such as europium(II) oxide (EuO), europium(II) chloride (EuCl₂), and europium(II) sulfate (EuSO₄), it is found in the +2 oxidation state.

The +3 oxidation state is also observed in europium compounds, such as europium(III) oxide (Eu₂O₃) and europium(III) chloride (EuCl₃), but it is less common compared to the +2 oxidation state.