The low temperature heat capacities and thermodynamic functions of fluorofullerenes C60F48 and C60F46.

A. I. Druzhinina, N. A. Galeva, R. M. Varushchenko, O. V. Boltalina, L. N. Sidorov

" Fullerenes. Recent advances in the chemistry and physics of fullerenes and related materials", edited by Karl M.Kadish and Rodney S. Ruoff, published by: the Electrochemical Society, Inc. 10 South Main Street, Pennington, New Jersey , v. 5, pp. 1203-1211, (1998)

ABSTRACT. The heat capacities of fluorinated fullerenes C60F48 and C60F46 have been measured in an adiabatic automatic calorimeter over the temperature range from 5 to 356 K. The heat capacity curve of C60F48 reveals gradual lambda transition between temperatures 315 K and 345 K. Thermodynamic properties of C60F48 in the transition range are as follows: Ttrs = 329.6+-0.4 K, DtrsH = 7.0+-0.7 kJ*mol-1 and DtrsS = 21+-2 J*K-1*mol-1. The cp curve of C60F46 exhibits glassy crystal-to-crystal transition in the temperature interval from 210 K to 245 K. The thermodynamic functions HT0- H00, ST0- S00 and GT0- H00of C60F48 and C60F46 have been calculated on the basis of the heat capacity data.

Laboratory of Thermochemistry