Heat Capacity and Standard Thermodynamic Functions of Triphenylantimony Bis(1-adamantanecarboxylate) over the Range from (0 to 520) K

Abstract

Heat capacities of triphenylantimony bis(1-adamantanecarboxylate) Ph3Sb[OC(O)C10H15]2 were measured with a precision adiabatic vacuum calorimeter over the temperature range from T = (6 to 353) K and with differential scanning calorimeter over the temperature range from T = (320 to 520) K. The thermal behavior of the compound under study was investigated over the range from T = (250 to 530) K. It was revealed that triphenylantimony bis(1-adamantanecarboxylate) could exist in crystalline, liquid, glassy, and overcooled liquid states. On the obtained data, the standard thermodynamic functions of molar heat capacity Cp,m, enthalpy H(T) – H(0), entropy S(T), and Gibbs energy G(T) – H(0) of Ph3Sb[OC(O)C10H15]2 were calculated over the range from T = (0 to 498) K. The low-temperature (T < 50 K) heat capacity dependence was analyzed on the basis of Debye’s heat capacity theory of solids and its multifractal model, so the characteristic temperature and the fractal dimension were determined, and chain-layered structure topology was established. The standard entropy of formation at T = 298.15 K of Ph3Sb[OC(O)C10H15]2 (cr) ΔfSm(298.15, Ph3Sb[OC(O)C10H15]2, cr) = (−2885 ± 8) J·K–1·mol–1 was calculated. Some thermodynamic properties of triphenylantimony bis(1-adamantanecarboxylate) were compared with similar data of other organic derivatives of antimony(V) studied earlier.