On the basis of lanthanoid contraction, explain the following:
(a) Nature of bonding in and .
(b) Trends in the stability of oxo-salts of lanthanoids from .
(c) Stability of the complexes of lanthanoids.
(d) Radii of 4d and 5d-block elements.
(e) Trends in acidic character of lanthanoid oxides.
(a). Covalent character of bond increases as the size of atom decreases. La is larger than Lu (Lanthanide contraction), hence, displays more ionic behaviour, but displays more covalent behaviour.
(b). Decrease in size of atoms, also leads to decrease in stability of the oxo-salts.
(c). Decrease in size of atoms, corresponds with production of lower stable compounds.
(d). 4d and 5d block elements in the same column have nearly equal radii.
(e) There is an increase in the acidic nature of oxides as the size decreases.