Fajan’s rules

Explain each the following, using Fajan s rules ... 

Basicity of Ions Due to lanthanide contraction from La3+ to Lu3+ covalent character increases between Lanthanide(III) ions and OH- ions. Thus La(OH)3 is most basic while Lu(OH)3 is least basic. According to Fajan s rule (Basicity decreases as ion size decreases). These differences in basicity are reflected in... 

Charge density gives a measure of how much and how tightly packed the charge is around an atom. According to Fajan s rule, the charge density of a cation affects the extent of covalent bonding. See Chapter 11 for more details... 

Type of charge on a particle could be determined by the measurement of Zeta potential [9] or a titration curve. According to Fajan s rule [10], the ions forming a crystalline phase should be adsorbed prior to other ions. For the system studied in this paper, the sol particles produced must carry positive charge to make it stably adsorb the cationic surfactant. In order to elucidate the effect... 

Fajan s rules dictate that the partial covalent nature of a metal s ionic bond with an anion will increase with high charge of either of the interacting ions, small cation radius, or large anion radius. The covalent nature of the bond also is higher with a noninert gas electron configuration of the cation, e.g., the more covalent nature of Cu + ( Ar 3d ) bonds, in contrast to the ionic bonds formed by Na+ ( Ne ) (Barrett 2002). 

Fajan s third rule states that covalent character is greater for cations with a nonrare gas configuration than for those with a complete octet, charge and size being approximately equal. For example, Cu is more polarizing than Na (ions of approximately the same size) because the d electrons around Cu do not shield the nucleus as effectively as the complete octet in Na. ... 

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