Abstract
Lanthanide(III) ion chelates with a Schiff base derived from sulphapyridine and salicylaldehyde have been characterised by molar conductance, magnetic moment and spectral data. Coordination of the lanthanide ions occurs through both the phenolic oxygen and the azomethine nitrogen of the Schiff base and two water molecules.
The stability constants of the metal chelates were determined potentiometrically and followed the order La < Ce < Pr = Nd < Dy < Er. A plot of log K versus e 2/r shows an approximately linear relationship.