THERMODYNAMICS OF THE THALLIUM ALKANOATES .7. HEAT-CAPACITY AND THERMOPHYSICS OF THALLIUM(I) BUTANOATE AT TEMPERATURES FROM 6-K TO 480-K

The heat capacity of thallium(I) butanoate has been determined by adia batic calorimetry from temperatures T of 5 K to 350 K and by different ial-scanning calorimetry (d.s.c.) from 320 K to 480 K. A transition at T = (154.2 +/- 0.5) K, two very closely spaced crystalline-phase tran sitions at T = 285.3(6) K and 289.8(6) K as well as a crystal 1-to-iso tropic liquid transition at T = 456.7 K have been studied repeatedly b y adiabatic calorimetry and/or d.s.c. The standard molar entropies of the several transitions are IV-to-III, 1.278 - R; III-to-II, 1.235.R; II-to-I, 0.624.R, and I-to-isotropic 1, 2.02.R, respectively. Unlike h igher members in this series, no mesomorphic phase occurs between crys talline phase I and the isotropic liquid phase.