Tantalum is a transition metal that can exhibit a wide range of oxidation states, including +3, +4, +5, and +6. In ionic compounds, tantalum typically forms cations, with the most common being Ta³⁺ and Ta⁴⁺. Tantalum can also form anions, such as [TaF₆]³⁻ and [TaO₄]³⁻, in the presence of highly electronegative elements like fluorine and oxygen. These anions are formed by the complete loss of electrons from the tantalum atom.