T. Moeller, T. Hseu
Dec 1, 1962
Citations
0
Influential Citations
51
Citations
Journal
Journal of Inorganic and Nuclear Chemistry
Abstract
Abstract Interaction between trans -1,2-diaminocyclohexane-N,N′ tetra-acetic acid 4 DCTA or H 4 Z) and tripositive rare-earth metal ions has been investigated. The formation constants of the hydrogen chelates (LnHZ) and of the normal chelates (LnZ − ) have been evaluated at 20°C, 30°C and 40°C and an ionic strength of 0·10(KNO 3 ), the former by a titration technique and the latter by a mercury indicator-electrode technique. Enthalpy and entropy changes characterizing the formation of the normal chelates have been calculated at 25°C. These and functions of the partial molal entropy of the normal chelates have been compared with corresponding values for related chelating agents. The significance of a configurational entropy contribution is particularly apparent for the complexes of this somewhat sterically limited ligand.