Thermodynamics of metal cyanide co-ordination. Part VII. Log K, ΔH°, and ΔS° values for the interaction of CN– with Pd2+. ΔH° values for the interaction of Cl– and Br– with Pd2+

Abstract

Values of ΔG°, ΔH°, and ΔS° have been determined for the reactions Pd²⁺+ 4CN^–= Pd(CN)₄^2–, and Pd(CN)₄^2–+ CN^–= Pd(CN)₅^3– at 25° and zero ionic strength to be –57·8 kcal./mole, –92·3 kcal./mole, –116 cal./deg.-mole and –3·9 kcal./mole, –0·2 kcal./mole, 7·8 cal./deg.-mole, respectively. ΔH° values at 25° and 0·10 ionic strength for the reaction Pd²⁺+ 4X^–= PdX₄^2–(X = Cl or Br) are –5·5 and –13·1 kcal./mole, respectively, and for the reaction Pd²⁺+ 31^–= Pd(s)+ I₃^– is –24·9 kcal./mole. From this last value the calculated entropy of the aqueous Pd²⁺ ion is 11·1 cal./deg.-mole.