مرکز منطقه ای اطلاع رساني علوم و فناوري -

چكيده لاتين :

Acetohydroxamic acid, CH3CONHOH, forms highly stable complexes with vanadium (V) and vanadium (IV) in 1:1, 1:2 and 1:3 mole ratios. The stability of these complexes can be determined in terms of thermodynamic parameters; AG,AH and AS. The preliminary data, obtained through pH titration at various temperatures, was processed and analyzed by the computer program BEST for the refinement of graphically calculated log 0 values. Graphs of ln/3 versus 1/T, gave a straight line, with a slope —AH/R and intercept AS/R. Enthalpy and free energy changes for V(V) complexes were found in the order of ML > ML2 > ML3 with a negative sign. Whereas entropy change was found to be in the same order but positive, for vanadium (IV) acetohydroxamic acid complexes, the order of AG, AH and AS was ML > ML3 > ML2. The AS is most positive for a 1:1 complex, while AG and AH are more negative for the same.