Thermodynamics of thallium alkanoates VI. Thallium(I) n-heptanoate revisited

Abstract

The heat capacity of thallium(I) n-heptanoate has been remeasured on a new sample on which the preparative procedures were modified to eliminate the 1-1 (salt+acid) complex (soap) in a previously studied sample. The sub-ambient heat capacity of a new highly pure thallium(I) n-heptanoate is characterized by one set of transitions between 262 and 272 K and another transition at 301 K. The lowest transition temperature at 262.1 K has a maximum of Cp, m ~ 559R. Next, a bifurcated pair (at 268.6 and 271.4K) have Cp, m ~ 300R, and the highest transition (at 301.0 K) has a maximum Cp, m ~ 1697R. The corresponding values of ΔtrsSmo for the two sets are about 2.24R and 1.10R. At 298.15 K the values of Δ0TSmo, Δ0THmo, and Φmo(T) are 39.79R, 5979R·K, and 19.74R. Smoothed thermodynamic functions at selected temperatures are tabulated through melting.