Heat Capacity and Standard Thermodynamic Functions of a Fullerene Complex, ((CH₃)₃Si)₁₂C₆₀, over the Range fromT→ 0 K toT= 350 K

Abstract

Low-temperature heat capacities of the crystalline fullerene complex ((CH 3 ) 3 Si) 12 C 60 have been measured by a precision adiabatic calorimeter over the temperature range from T ) (6.5 to 350) K for the first time. The experimental results have been used to calculate the standard (p o ) 0.1 MPa) thermodynamic functions: molar heat capacities, C p,m o , enthalpy, H o (T) -H o (0), entropy, S o (T), and Gibbs energy, G o (T) -H o (0), of ((CH 3 ) 3 Si) 12 C 60 (cr) over the range from T f 0 K to T ) 350 K. The low-temperature (T < 50 K) dependence of the heat capacity was analyzed on the basis of Debye's heat capacity theory of solids and its fractal variant. Following that analysis, the characteristic temperatures as well as the fractal dimension were determined, and some conclusions about the structure topology were made. The standard entropy of formation at T ) 298.15 K of ((CH 3 ) 3 Si) 12 C 60 (cr) was calculated. The standard thermodynamic properties of tested fullerene complex and previously studied C 60 fullerite/fullerene complex (t-Bu) 12 C 60 were compared.

Heat capacities and thermodynamic properties of MgNDC

“…Heat capacities determinations of various compounds have attracted many researchers' attention [10][11][12]. Molar heat capacities of the materials at different temperatures are basic data in chemistry and engineering, from which many other thermodynamic properties such as enthalpy and entropy can be calculated.…”