Department of Chemistry, Govt. P.G. College, Khair, Aligarh, (India)
Online published on 27 January, 2017.
Mixed ligand complexes of some rare earth metals viz, La (III), Pr (III), Nd (III), Gd(III) and Dy(III) have been investigated potentiometrically with tripotassium salt of Ethylenediamine-N, N, N’, N’ – tetra acetic acid (K3EDTA), Thiophene-2-carboxylic acid (TCA), Furan-2-Carboxylic acid (FA) and dibasic acid such as oxalic acid (ox), Succinic acid (SUC) in aqueous solution at 40±1°C and at an ionic strength of 0.1 mol dm−3 (KNO3). The stability constants of these 1:1:1:1, quaternary complexes, have been evaluated by various computational methods. The relative order of stability in terms of La(III) < Pr(III) < Nd(III) Gd(III) < Dy(III) metal ion has been observed, which is almost in accordance with the increasing Φ =charge/radius ratio. The change in thermodynamic parameter (free energy change, ΔGo) has also been calculated under the same conditions.
La (III), Pr (III), Nd (III), Gd (III) and Dy (III), potentiometrically, Furan-2- Carboxylic acid (FA), stability constants, thermodynamic parameter
