eng Ansari Education and Research Society Journal of Ultra Chemistry 0973-3450 2319-8036 August 2009 5 2 131 136 juc 694 article Rajesh Kant Chaudhary 1 Anjani Kumar Mishra 2 Prem Mohan Mishra 3 At+P.O.-Shubhankarpur, Darbhanga- 846004 (INDIA) M.R.M. College, Darbhanga Department of Chemistry, M.L.S.M. College, Darbhaga, Bihar (INDIA) <p style="text-align: justify;">In continuation of the previous work, practical proton ligand and metal ligand stability constants of the metal ions Y(III), Nd(III) and Pr(III) with glutamic acid ligand at temperature 203 K at constant ionic strength of 0.1 M KNO₃ was determined. The stability constant was determined by the method of Bjerrum Calvin pH titration technique as adopted by Irving and Rossotti^1-2. The stability constant of metal complexes with glutamic acid shows the sequence Y (III) &gt; Nd(III) &gt; Pr (III). Thermodynamic parameters such as free energy (DG), enthalpy charge (DH) and entropy charge DS also have been calculated.</p> <p>&nbsp;</p> https://journalofchemistry.org/paper/694/ Stability constant pH metric method Rare earth complexes Glutamic acid ligand Free energy change of complexation