Low-temperature heat capacities of the coordination compound Zn(Phe) 3 (NO 3 ) 2 .H 2 O(s) have been precisely measured over the temperature range between T=78K and T=373K through a small sample precision automated adiabatic calorimeter. Experimental heat capacities have been fitted into a polynomial equation of heat capacities (C p , m ) with the reduced temperatures (x), [x=f(T)]. The initial dehydration temperature of the complex (T d ) has been given from analysis of the heat-capacity curve, T d =327.25K. Dissolution enthalpies of [ZnSO 4 .7H 2 O(s)+2NaNO 3 (s)+3L-Phe(s)](Δ d H m , 1 0 ) and [Zn(Phe) 3 (NO 3 ) 2 .H 2 O(s)+Na 2 SO 4 (s)](Δ d H m , 2 0 ) in 100mL of 2 molar HCl at T=298.15K have been measured by means of an isoperibol solution calorimeter: Δ d H m , 1 0 =(115.430+/-2.797)kJ.mol - 1 , Δ d H m , 2 0 =(67.211+/-2.147)kJ.mol - 1 . The standard molar enthalpy of formation of the complex has been determined to be: Δ f H m 0 =-(2292.44+/-11.12)kJ.mol - 1 , through a Hess thermochemical cycle from the results of molar dissolution enthalpies and other auxiliary thermodynamic data.
