Thermodynamics of thallium alkanoates II. Heat capacity and thermodynamic functions of thallium(I) n-heptanoate

Abstract

The sub-ambient heat capacity of thallium(I) n-heptanoate is characterized by two sets of transitions between 262 and 301 K. The lowest transition (at 262.8 K) has a maximum Cp, m/R [approximate] 700. Next, a bifurcated pair (at 267.8 and 271.7 K) has (Cp, m/R)'s [approximate] 200, and the highest bifurcated pair (at 297.2 and 300.9 K) has maximum (Cp, m/R)'s [approximate] 450 and [approximate] 16000. The corresponding values of [Delta]trsSmo/R for the two sets are about 1.935 and 2.215. The heat capacities are in fair accord with the d.s.c. values of Fernandez-Martin, Lopez de la Fuente, and Cheda over the common range of superambient values. At 298.15 K the values of {Smo(T)-Smo(0)}/R, {Hmo(T)-Hmo(0)}/R, and -{Gmo(T)-Hmo(0)}/RT are 38.58, 5514.7 K, and 20.30. Smoothed thermodynamic values are tabulated at selected temperatures through melting.