Question

On the basis of lanthanoid contraction, explain the following:

(i) Nature of bonding in La₂O₃ and Lu₂O₃.
(ii) Trends in the stability of oxosaltes of lanthanoids from La to Lu.
(iii) Stability of complexes of lanthanides.
(iv) Radii of 4d and 5d block elements.
(v) Trends in the acidic character of lanthanoid oxides.

Answer 1

(i) As the size decreases, the covalent character increases. Therefore La₂O₃ is more ionic and Lu₂O₃ is more covalent.

(ii) As the size decreases from La to Lu, the stability of oxo salts also decreases.

(iii) Stability of the complexes increases as the size of the lanthanoid decreases.

(iv) Radii of 4d and 5d block elements are will be almost the same.

(v) Acidic character of the oxides increases from La to Lu.