Explain Comparison of Lanthanides and Actinides

Lanthanides and Actinides both show close resemblance because these involve filling of f-subshells. Both have colored ions, low electronegativity, high re-activity and show magnetic properties. However, these also differ from each other as shown in the following explanation.

Lanthanides

• Binding energies of 4f electrons are higher.
• Maximum oxidation satate exhibited by lanthanides is +4 e.g. Ce⁴⁺
• 4f electrons have greater shielding effect.
• Most of their ions are colourless.
• They are paramagnetic but magnetic properties can be easily explained.
• They do not form complexes easily.
• Except promethium, they are non-radioactive.
• Their compounds are less basic.
• They do not form oxocations.

Actinides

• Binding energies of 5f electrons are lower.
• Due to lower binding energies they show higher oxidation states such as +4, +5 and +6. Uranium exhibits +6 oxidation state in UF₆ and UO₂Cl₂
• 5f electrons have poor shielding effect.
• Most of their ions are coloured U³⁺ (red), U⁴⁺ (green) and UO₂²⁺ (yellow)
• They are also paramagnetic but their magnetic properties are very difficult to interpret.
• They have much greater tendency to form complexes.
• All of them are radioactive.
• Their compounds are more basic.
• They form oxocations such as UO₂²⁺, UO⁺, NpO₂⁺, PuO²⁺.