The low temperature heat capacities of fluorofullerenes

✍ Scribed by A.I. Druzhinina; N.A. Galeva; R.M. Varushchenko; O.V. Boltalina; L.N. Sidorov

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 142 KB
• Volume: 31
• Category: Article
• ISSN: 0021-9614
• DOI: 10.1006/jcht.1999.0523

✦ Synopsis

The heat capacities of the fluorinated fullerenes C 60 F 48 , C 60 F 46 , and C 60 F 36 have been measured in an adiabatic vacuum calorimeter over the temperature range from 8 K to 356 K. The heat capacity curve of C 60 F 48 reveals a gradual "order-disorder" transition between the temperatures 315 K and 345 K. Thermodynamic properties of C 60 F 48 in the transition region are as follows:

F 46 exhibits a glassy crystal transition in the temperature interval from 210 K to 245 K. The temperature dependence of the heat capacity of C 60 F 36 does not indicate any anomaly. The molar thermodynamic functions H o m (T ) -H o m (0), S o m (T ) -S o m (0), and G o m (T ) -H o m (0) over the temperature range studied and entropies of formation T f S o m at T = 298.15 K have been calculated for C 60 F 48 , C 60 F 46 , and C 60 F 36 .